Conversion of units

Conversion of units refers to conversion factors between different units of measurement for the same quantity. Template:TOCright

Techniques

Dimensioned values

Carrying units through a mathematical operation is sometimes performed.

e.g. to convert 6 feet into metres. From below one foot is exactly 0.3048 metre. Thus:

6 ft × 0.3048 m/ft = 1.8288 m

This leaves only metres, the desired result.

This works because the numerator and denominator describe the same quantity, the factor is equivalent to the number 1. Therefore, multiplication by this factor does not change the measured quantity, only its units.

Rounding of results

The process of making a conversion cannot produce a more precise result than the original quoted figure. Appropriate rounding of results is normally performed after conversion. (See significant figures).

In the above example the 0.3048 metre per foot is precise by definition, but the precision of the answer is determined by the precision of the 6 ft figure and in many cases the result would need rounding perhaps to 1.8 m.

Tables of conversion factors

Legend

Legend
≡	definition
=	exactly equal to
≈	approximately equal to
(`digits`)	indicates the digits repeat infinitely

Luminance

Luminance
Name of unit	Symbol	Definition	Relation to SI units
candela per square metre (SI base unit)		≡ cd/m²	= 1 cd/m²
lambert	L	≡ (10⁴/π) cd/m²	≈ 3183.09886 cd/m²

Length

Length
Name of unit	Symbol	Definition	Relation to SI units
metre (SI base unit)	m	≡ 1 m	= 1 m
ångström	Å	= 0.1 nm	≡ 1Template:E m
astronomical unit	AU	Mean distance from Earth to the Sun	= 149 597 870 691 ± 30 m
atomic unit of length	a₀	≡ Bohr radius of hydrogen	≈ 5.29 177 208 59Template:E ± 3.6Template:E m^[1]
barley corn		≡ ⅓ in	= 0.0846 m
Bohr radius	a₀; b	≡ α/4πR_∞	≈ 5.291 772 083Template:E ± 19Template:E m
cable length (Imperial)		≡ 608 ft	= 185.3184 m
cable length (International)		≡ 1/10 nmi	= 185.2 m
cable length (U.S.)		≡ 720 ft	= 219.456 m
calibre	cal	≡ 1 in	= 0.0254 m
chain (Gunter's; Surveyor's)	ch	≡ 66.0 ft (4 rods)	= 20.1168 m
chain (Ramsden's; Engineer's)	ch	≡ 100 ft	= 30.48 m
cubit		≡ 18 in	= 0.4572 m
ell	ell	≡ 45 in	= 1.143 m
fathom	fm	≡ 6 ft	= 1.8288 m
fathom	fm	≈ 1/1000 nmi^{[citation needed]}	= 1.852 m
fermi	fm	≡ 1Template:E m	= 1Template:E m
finger		≡ 7/8 in	= 0.00022225 m
finger (cloth)		≡ 4 ½ in	= 0.1143 m
foot (Benoît)	ft (Ben)		≈ 0.304 799 735 m
foot (Clarke's; Cape)	ft (Cla)		≈ 0.304 797 265 4 m
foot (Indian)	ft Ind		≈ 0.304 799 514 m
foot (International)	ft	≡ 12 inches = 1/3 yd	= 0.3048 m
foot (Sear's)	ft (Sear)		≈ 0.304 799 47 m
foot (U.S. Survey)	ft (US)	≡ 1200/3937 m ^[2]	≈ 0.304 800 610 m
french; charriere	F	≡ 1/3 mm	= 3.3 Template:E m
furlong	fur	≡ 10 chains = 660 ft =220 yd	= 201.168 m
geographical mile		≡ 6082 ft	= 1853.7936 m
hand		≡ 4 in	= 0.1016 m
inch	in	≡ 1/36 yd = 1/12 ft	= 0.0254 m
league	lea	≡ 3 mi	= 4828.032 m
light-day		≡ 24 light-hours	= 2.590 206 837 12Template:E m
light-hour		≡ 60 light-minutes	= 1.079 252 848 8Template:E m
light-minute		≡ 60 light-seconds	= 1.798 754 748Template:E m
light-second			≡ 2.997 924 58Template:E m
light-year	l.y.	≡ c₀ × 86 400 × 365.25	= 9.460 730 472 580 8Template:E m
line	ln	≡ 1/12 in (Klein 1988, 63)	≈ 0,00 002 116 667 m
link (Gunter's; Surveyor's)	lnk	≡ 1/100 ch	= 0.201 168 m
link (Ramsden's; Engineer's)	lnk	≡ 1 ft	= 0.3048 m
mickey		≡ 1/200 in	= 1.27Template:E m
micron	µ		≡ 1Template:E m
mil; thou	mil	≡ 1Template:E in	= 2.54Template:E m
mil (Sweden and Norway)	mil	≡ 10 km	= 10000 m
mile	mi	≡ 1760 yd = 5280 ft	= 1609.344 m
mile (U.S. Survey)	mi	≡ 5280 ft (US)	= 5280 × 1200/3937 m ≈ 1609.347 219 m
nail (cloth)		≡ 2 ¼ in	= 0.000 571 5 m
nautical league	NL; nl	≡ 3 nmi	= 5556 m
nautical mile(international)	NM; nmi	≡ 1852 m ^[3]	1852 m
nautical mile (Admiralty)	NM (Adm); nmi (Adm)	≡ 6080 ft	≡ 1853.184 m
pace		≡ 2.5 ft	= 0.762 m
palm		≡ 3 in	= 0.000 762 m
parsec	pc		= 3.08567782 Template:E ± 6Template:E m ^[4]
point (ATA)	pt	≡ 0.013837 in^{[citation needed]}	= 0.000 351 459 8 m
point (Didot; European)	pt		≡ 0.000 376 065 m^{[citation needed]}
point (metric)	pt	≡ 3/8 mm	= 0.000 375 m^{[citation needed]}
point (PostScript)	pt	≡ 1/72 in	≈ 0.000 352 778 m
quarter		≡ ¼ yd	= 0.2286 m
rod; pole; perch	rd	≡ 16 ½ ft	= 5.0292 m
rope	rope	≡ 20 ft	= 6.096 m
span		≡ 6 in	= 0.1524 m
span (cloth)		≡ 9 in	= 0.2286 m
spat[3]		≡ 10¹² m	= 1×10¹² m
stick		≡ 2 in	= 0.05 08 m
stigma; pm		≡ 1Template:E m	≡ 1Template:E m
telegraph mile	mi	≡ 6087 ft	= 1855.3176 m
twip	twp	≡ 1/1440 in	≈ 1.763 889Template:E m
x unit; siegbahn	xu		≈ 1.0021Template:E m
yard (International)	yd	≡3 ft ≡ 36 in	= 0.9144 m^[2]

Area

Area
Name of unit	Symbol	Definition	Relation to SI units
acre	ac	≡ 10 sq ch = 4840 sq yd	= 4046.856 422 4 m²
are	a		≡ 100 m²
barn	b		≡ 10⁻²⁸ m²
barony		≡ 4000 ac	= 1.618 742 568 96Template:E m²
board	bd	≡ 1 in × 1 ft	= 7.741 92Template:E m²
boiler horsepower equivalent direct radiation	bhp EDR	≡ (1 ft²) (1 bhp) / (240 BTU_IT/h)	≈ 12.958 174 m²
circular inch	circ in	≡ π/4 sq in	≈ 5.067 075Template:E m²
circular mil; circular thou	circ mil	≡ π/4 mil²	≈ 5.067 075Template:E m²
cord		≡ 192 bd	= 1.486 448 64 m²
dunam		≡ 1000 m²	= 1000 m²
hectare	ha	≡ 10 000 m²	= 10 000 m²
hide		≡ 100 ac	= 4.046 856 422 4Template:E m²
rood	ro	≡ ¼ ac	= 1011.714 105 6 m²
shed			≡ 10⁻⁵² m²
square chain	sq ch	≡ 1 sq ch	= 404.685 642 24 m²
square foot	sq ft	≡ 1 ft × 1 ft	= 9.290 304Template:E m²
square inch	sq in	≡ 1 in × 1 in	= 6.4516Template:E m²
square kilometre	km²	≡ 1 km²	= 10⁶ m²
square link	sq lnk	≡ 1 lnk²	= 4.046 856 422 4Template:E m²
square metre (SI unit)	m²	≡ 1 m × 1 m	= 1 m²
square mil; square thou	sq mil	≡ 1 mil × 1 mil	= 6.4516Template:E m²
square mile; section	sq mi	≡ 1 mi × 1 mi	= 2.589 988 110 336Template:E m²
square rod/pole/perch	sq rd	≡ 1 sq rd	= 25.292 852 64 m²
square U.S. Survey foot	sq ft	≡ 1 sq ft (US)	≈ 9.290 341 161 327 49Template:E m²
square U.S. Survey mile	sq mi	≡ 1 sq mi (US)	≈ 2.589 998Template:E m²
square yard	sq yd	≡ 1 yd × 1 yd	= 0.836 127 36 m²
stremma		≡ 1000 m²	= 1000 m²
township		≡ 36 sq mi (US)	≈ 9.323 994Template:E m²
yardland		≡ 30 ac	= 1.214 056 926 72Template:E m²

Volume

Volume
Name of unit	Symbol	Definition	Relation to SI units
acre foot	ac ft	≡ 1 ac x 1 ft = 43560 ft³	= 1233.481 837 547 52 m³
cubic metre (SI unit)	m³	≡ 1 m × 1 m × 1 m	= 1 m³
litre	L	≡ 1 dm³ ^[5]	= 0.001 m³
lambda	λ	≡ 1 mm³	= 1 Template:E m³
drop (metric)		≡ 1/20 mL	= 5 Template:E m³
minim (Imperial)	min	≡ 1/480 fl oz (Imp) = 1/60 fl dr (Imp)	≈ 5.9 193 880 208 333 Template:E m³
minim (U.S.)	min	≡ 1/480 US fl oz = 1/60 US fl dr	= 6.1 611 519 921 875 Template:E m³
drop (U.S.) (alt)	gtt	≡ 1/456 US fl oz	≈ 6.4 854 231 Template:E m³
drop (Imperial) (alt)	gtt	≡ 1/1824 gi (Imp)	≈ 7.7 886 684 Template:E m³
drop (U.S.)	gtt	≡ 1/360 US fl oz	= 8.2 148 693 229 16 Template:E m³
drop (medical)		≡ 1/12 mL	= 83 Template:E m³
drop (Imperial)	gtt	≡ 1/288 fl oz (Imp)	= 9.8 656 467 0138 Template:E m³
dash (U.S.)		≡ 1/96 US fl oz = ½ US pinch	= 0.0308 057 599 609 375 Template:E m³
dash (Imperial)		≡ 1/384 gi (Imp) = ½ pinch (Imp)	= 0.0369 961 751 302 083 Template:E m³
pinch (U.S.)		≡ 1/48 US fl oz = ⅛ US tsp	= 0.0616 115 199 218 75 Template:E m³
pinch (Imperial)		≡ 1/192 gi (Imp) = ⅛ tsp (Imp)	= 0.0739 923 502 604 16 Template:E m³
fluid scruple (Imperial)	fl s	≡ 1/24 fl oz (Imp)	= 0.1183 877 604 16 Template:E m³
fluid drachm (Imperial)	fl dr	≡ ⅛ fl oz (Imp)	= 0.3551 632 812 5 Template:E m³
fluid dram (U.S.); U.S. fluidram	fl dr	≡ ⅛ US fl oz	= 0.3696 691 195 312 5 Template:E m³
teaspoon (Canadian)	tsp	≡ 1/6 fl oz (Imp)	≈ 0.4735 510 416 667 Template:E m³
teaspoon (U.S.)	tsp	≡ 1/6 US fl oz	= 0.4928 921 595 Template:E m³
teaspoon (metric)			≡ 0.5 Template:E m³
teaspoon (Imperial)	tsp	≡ 1/24 gi (Imp)	= 0.5919 388 020 83 Template:E m³
dessertspoon (Imperial)		≡ 1/12 gi (Imp)	= 1.1838 776 0416 Template:E m³
tablespoon (Canadian)	tbsp	≡ ½ fl oz (Imp)	= 1.4206 531 25 Template:E m³
tablespoon (U.S.)	tbsp	≡ ½ US fl oz	= 1.4786 764 782 5 Template:E m³
tablespoon (metric)			≡ 1.5 Template:E m³
cubic inch	cu in	≡ 1 in × 1 in × 1 in	= 1.6387 064 Template:E m³
tablespoon (Imperial)	tbsp	≡ 5/8 fl oz (Imp)	= 1.7758 164 0625 Template:E m³
pony		≡ 3/4 US fl oz	= 2.218 014 717 187 5 Template:E m³
fluid ounce (Imperial)	fl oz (Imp)	≡ 1/160 gal (Imp)	= 2.8413 062 5 Template:E m³
fluid ounce (U.S.)	US fl oz	≡ 1/128 gal (US)	= 2.9573 529 5625 Template:E m³
shot		≡ 1 US fl oz	= 2.9573 529 5625 Template:E m³
jigger		≡ 1½ US fl oz	= 4.4360 294 343 75 Template:E m³
gill (U.S.)	gi (US)	≡ 4 US fl oz	= 11.8294 118 25 Template:E m³
gill (Imperial); Noggin	gi (Imp); nog	≡ 5 fl oz (Imp)	= 14.2065 312 5 Template:E m³
cup (Canadian)	c (CA)	≡ 8 fl oz (Imp)	= 22.73045 Template:E m³
cup (U.S.)	c (US)	≡ 8 US fl oz ≡ 1/16 gal (US)	= 23.6588 2365 Template:E m³
cup (metric)	c		≡ 25.0 Template:E m³
breakfast cup		≡ 10 fl oz (Imp)	= 28.4130 625 Template:E m³
pint (U.S. fluid)	pt (US fl)	≡ ⅛ gal (US)	= 47.3176 473 Template:E m³
pint (U.S. dry)	pt (US dry)	≡ 1/64 bu (US lvl) ≡ ⅛ gal (US dry)	= 0.000 550 610 471 3575 m³
pint (Imperial)	pt (Imp)	≡ ⅛ gal (Imp)	= 0.000 568 261 25 m³
fifth		≡ 1/5 US gal	= 0.000 757 082 356 8 m³
quart (U.S. fluid)	qt (US)	≡ ¼ gal (US fl)	= 0.000 946 352 946 m³
quart (U.S. dry)	qt (US)	≡ 1/32 bu (US lvl) = ¼ gal (US dry)	= 0.001 101 220 942 715 m³
quart (Imperial)	qt (Imp)	≡ ¼ gal (Imp)	= 0.001 136 522 5 m³
pottle; quartern		≡ ½ gal (Imp) = 80 fl oz (Imp)	= 0.002 273 045 m³
board-foot	fbm	≡ 144 cu in	= 0.002 359 737 216 m³
gallon (U.S. fluid; Wine)	gal (US)	≡ 231 cu in	= 0.003 785 411 784 m³
gallon (U.S. dry)	gal (US)	≡ ⅛ bu (US lvl)	= 0.004 404 883 770 86 m³
gallon (Imperial)	gal (Imp)	≡	= 0.004 546 09 m³
beer gallon	beer gal	≡ 282 cu in	= 0.004 621 152 048 m³
peck (U.S. dry)	pk	≡ ¼ US lvl bu	= 0.008 809 767 541 72 m³
peck (Imperial)	pk	≡ 2 gal (Imp)	= 0.009 092 18 m³
bucket (Imperial)	bkt	≡ 4 gal (Imp)	= 0.018 184 36 m³
timber foot		≡ 1 cu ft	= 0.028 316 846 592 m³
cubic foot	cu ft	≡ 1 ft × 1 ft × 1 ft	= 0.028 316 846 592 m³
firkin		≡ 9 gal (US)	= 0.034 068 706 056 m³
bushel (U.S. dry level)	bu (US lvl)	≡ 2150.42 cu in	= 0.035 239 070 166 88 m³
bushel (Imperial)	bu (Imp)	≡ 8 gal (Imp)	= 0.036 368 72 m³
bushel (U.S. dry heaped)	bu (US)	≡ 1 ¼ bu (US lvl)	= 0.044 048 837 708 6 m³
strike (U.S.)		≡ 2 bu (US lvl)	= 0.070 478 140 333 76 m³
strike (Imperial)		≡ 2 bu (Imp)	= 0.072 737 44 m³
kilderkin		≡ 18 gal (Imp)	= 0.081 829 62 m³
sack (U.S.)		≡ 3 bu (US lvl)	= 0.105 717 210 500 64 m³
sack (Imperial); bag		≡ 3 bu (Imp)	= 0.109 106 16 m³
barrel (U.S. dry)	bl (US)	≡ 105 qt (US) = 105/32 bu (US lvl)	= 0.115 628 198 985 075 m³
barrel (U.S. fluid)	fl bl (US)	≡ 31½ gal (US)	= 0.119 240 471 196 m³
coomb		≡ 4 bu (Imp)	= 0.145 474 88 m³
barrel (petroleum)	bl; bbl	≡ 42 gal (US)	= 0.158 987 294 928 m³
barrel (Imperial)	bl (Imp)	≡ 36 gal (Imp)	= 0.163 659 24 m³
hogshead (U.S.)	hhd (US)	≡ 2 fl bl (US)	= 0.238 480 942 392 m³
seam		≡ 8 bu (US lvl)	= 0.281 912 561 335 04 m³
quarter; pail		≡ 8 bu (Imp)	= 0.290 949 76 m³
hogshead (Imperial)	hhd (Imp)	≡ 2 bl (Imp)	= 0.327 318 48 m³
cord-foot		≡ 16 cu ft	= 0.453 069 545 472 m³
butt, pipe		≡ 126 gal (wine)	= 0.476 961 884 784 m³
perch	per	≡ 16½ ft × 1½ ft × 1 ft	= 0.700 841 953 152 m³
cubic yard	cu yd	≡ 27 cu ft	= 0.764 554 857 984 m³
tun		≡ 252 gal (wine)	= 0.953 923 769 568 m³
displacement ton		≡ 35 cu ft	= 0.991 089 630 72 m³
water ton		≡ 28 bu (Imp)	= 1.018 324 16 m³
freight ton		≡ 40 cu ft	= 1.132 673 863 68 m³
wey (U.S.)		≡ 40 bu (US lvl)	= 1.409 562 806 675 2 m³
load		≡ 50 cu ft	= 1.415 842 329 6 m³
register ton		≡ 100 cu ft	= 2.831 684 659 2 m³
last		≡ 80 bu (Imp)	= 2.909 497 6 m³
cord (firewood)		≡ 8 ft × 4 ft × 4 ft	= 3.624 556 363 776 m³
cubic fathom	cu fm	≡ 1 fm × 1 fm × 1 fm	= 6.116 438 863 872 m³
acre-inch		≡ 1 ac × 1 in	= 102.790 153 128 96 m³
cubic mile	cu mi	≡ 1 mi × 1 mi × 1 mi	= 4,168,181,825.440 579 584 m³

Angle

Angle
Name of unit	Symbol	Definition	Relation to SI units
radian (SI unit)	rad	≡ 180°/π	1 rad
centesimal second of arc	"	≡ 1 grad/10000	≈ 1.57 079 6Template:E rad
arcsecond	"	≡ 1°/3600	≈ 4.84 813 7Template:E rad
centesimal minute of arc	'	≡ 1 grad/100	≈ 15.708 0Template:E rad
minute of arc	'	≡ 1°/60	≈ 29.088 8Template:E rad
angular mil	µ	≡ 2π/6400 rad	≈ 9.8174 8Template:E rad
grad; gradian; gon	grad	≡ 2π/400 rad = 0.9°	≈ 1.570 796 3Template:E rad
degree (of arc)	°	≡ π/180 rad	≈ 1.745 329 3Template:E rad
sign		≡ 30°	≈ 0.523 599 rad
octant		≡ 45°	≈ 0.785 398 rad
sextant		≡ 60°	≈ 1.047 198 rad
quadrant		≡ 90°	≈ 1.570 796 rad

Solid angle

Solid angle
Name of unit	Symbol	Definition	Relation to SI units
steradian	sr		(SI derived unit)

Mass

Note: see Weight for detail of mass/weight distinction and conversion

Mass
Name of unit	Symbol	Definition	Relation to SI units
kilogram, grave(SI base unit)	kg; G		= 1kg
electron rest mass	m_e		≈ 9.109 381 88Template:E ± 72Template:E kg
atomic unit of mass	amu^{[citation needed]}	≡ m_e	≈ 9.109 381 88Template:E ± 72Template:E kg
unified atomic mass unit	u		≈ 1.660 538 73Template:E ± 13Template:E kg
dalton	Da		≈ 1.660 902 10Template:E ± 13Template:E kg
gamma	γ		≡ 1 Template:E kg
point		≡ 1/100 kt (metric)	= 2 Template:E kg
mite		≡ 1/20 gr	= 3.239 945 5 Template:E kg
mite (metric)		≡ 1/20 g	= 50 Template:E kg
grain	gr		≡ 64.798 91 Template:E kg
crith			≈ 89.9349 Template:E kg
carat (metric)	ct		≡ 200 Template:E kg
carat	kt	≡ 3 1/6 gr	≈ 205.196 548 333 Template:E kg
sheet		≡ 1/700 lb av	= 647.9891 Template:E kg
scruple (apothecary)	s ap	≡ 20 gr	= 1.295 978 2 Template:E kg
pennyweight	dwt; pwt	≡ 1/20 oz t	= 1.555 173 84 Template:E kg
dram (avoirdupois)	dr av	≡ 27 11/32 gr	= 1.771 845 195 312 5 Template:E kg
dram (apothecary; troy)	dr t	≡ 60 gr	= 3.887 934 6 Template:E kg
hyl (CGS unit)		≡ 1 gee × 1 g × 1 s²/m	= 9.806 65 Template:E kg
ounce (avoirdupois)	oz av	≡ 1/16 lb	= 28.349 523 125 Template:E kg
assay ton (short)	AT	≡ 1 mg × 1 sh tn ÷ 1 oz t	≈ 29.166 667 Template:E kg
ounce (apothecary; troy)	oz t	≡ 1/12 lb t	= 31.103 476 8 Template:E kg
assay ton (long)	AT	≡ 1 mg × 1 long tn ÷ 1 oz t	≈ 32.666 667 Template:E kg
mark		≡ 8 oz t	= 248.827 814 4 Template:E kg
pound (troy)	lb t	≡ 5760 grains	= 0.373 241 721 6 kg
pound (avoirdupois)	lb av	≡ 7000 grains	= 0.453 592 37 kg
pound (metric)			≡ 0.5 kg
clove		≡ 8 lb av	= 3.628 738 96 kg
stone	st	≡ 14 lb av	= 6.350 293 18 kg
hyl (MKS unit)		≡ 1 gee × 1 kg × 1 s²/m	= 9.806 65 kg
quarter (Imperial)		≡ 1/4 long cwt = 2 st = 28 lb av	= 12.700 586 36 kg
slug; geepound	slug	≡ 1 gee × 1 lb av × 1 s²/ft	≈ 14.593 903 kg
bag (Portland cement)		≡ 94 lb av	= 42.637 682 78 kg
short hundredweight; cental	sh cwt	≡ 100 lb av	= 45.359 237 kg
long hundredweight	long cwt or cwt	≡ 112 lb av	= 50.802 345 44 kg
bag (coffee)		≡ 60 kg	= 60 kg
quintal (metric)	q		≡ 100 kg
wey		≡ 252 lb = 18 st (variants exist)	= 114.305 277 24 kg
long quarter (informal)		≡ ¼ long tn	= 254.011 727 2 kg
quarter (informal)		≡ ¼ short tn	= 226.796 185 kg
kip	kip	≡ 1000 lb av	= 453.592 37 kg
short ton	sh tn	≡ 2000 lb	= 907.184 74 kg
tonne (mts unit)	t		≡ 1000 kg
long ton	long tn or ton	≡ 2240 lb	= 1016.046 908 8 kg
barge		≡ 22 ½ sh tn	= 20,411.656 65 kg
Zentner	Ztr.	Definitions vary; see ^[6] and ^[7]. See also discussion at Talk:Conversion of units#Zentner

In physics, the pound of mass is sometimes written lbm to distinguish it from the pound-force (lbf). It should not be read as the mongrel unit "pound metre".

Time

Time, t
Name of unit	Symbol	Definition	Relation to SI units
second (SI base unit)	s		= 1 s
Planck time		≡ (G[[Dirac's constant\|Template:Unicode]]/c⁵)^½	≈ 1.351 211 818Template:E s
atomic unit of time	au	≡ a₀/(α·c)	≈ 2.418 884 254Template:E s
svedberg	S	≡ 10⁻¹³ s	= 100Template:E s
shake		≡ 10⁻⁸ s	= 10Template:E s
sigma		≡ 10⁻⁶ s	= 10Template:E s
jiffy		≡ 1/60 s	≈ .016667 s
jiffy (alternate)		≡ 1/100 s	= 10 ms
helek		≡ 1/1080 h	≈ 3.333333 s
minute	min		≡ 60 s
milliday	md	≡ 86 400 s / 1000	≡ 86.4 s
moment		≡ 90 s	≡ 90 s
ke(traditional)		≡ 1/100 d	≡ 864 s
quarter (of an hour)	ke	≡ 1/96 d	≡ 900 s
hour	h	≡ 60 min	= 3600 s
day	d	≡ 24 h	= 86 400 s
week	wk	≡ 7 d	= 604 800 s
fortnight		≡ 2 wk	= 1 209 600 s
month (hollow)	mo	≡ 29 d	= 2 505 600 s
month	mo	≡ 30 d	= 2 592 000 s
month (full)	mo	≡ 31 d	= 2 678 400 s
year (Calendar)	a, y, or yr	≡ 365 d	= 31 536 000 s
year (Gregorian)	a, y, or yr	≡ 365.2425 d	= 31 556 952 s
year (Julian)	a, y, or yr	≡ 365.25 d	= 31 557 600 s
sidereal year	a, y, or yr	≡ 365.256363 d	= 31 558 149.76 s
Olympiad		≡ 4 a of 365 d	= 1.2614Template:E s
lustre; lustrum		≡ 5 a of 365 d	= 1.5768Template:E s
octaeteris		≡ 8 a of 365 d	= 2.522 88Template:E s
decade		≡ 10 a of 365 d	= 3.1536Template:E s
enneadecaeteris; Metonic cycle		≡ 110 mo (hollow) + 125 mo (full) = 19 a of 365 d	= 5.996 16Template:E s
Callippic cycle		≡ 441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d	= 2.398 377 6Template:E s
century (Calendar)		≡ 100 a of 365 d	= 3.1536Template:E s
century (Julian)		≡ 100 a of 365.25 d	= 3.155 76Template:E s
Hipparchic cycle		≡ 4 Callippic cycles - 1 d	= 9.593 424Template:E s
millennium (Calendar)		≡ 1000 a of 365 d	= 3.1536Template:E s
millennium (Gregorian)		≡ 1000 a of 365.2425 d	= 3.155 695 2Template:E s
millennium (Julian)		≡ 1000 a of 365.25 d	= 3.155 76Template:E s
Sothic cycle		≡ 1461 a of 365 d	= 4.607 409 6Template:E s

Speed or velocity

Speed
Name of unit	Symbol	Definition	Relation to SI units
metre per second (SI unit)	m/s		≡ 1 m/s
foot per hour	fph	≡ 1 ft/h	≈ 8.466 667Template:E m/s
furlong per fortnight		≡ furlong/fortnight	≈ 1.663 095Template:E m/s
inch per minute	ipm	≡ 1 in/min	≈ 4.23 333Template:E m/s
foot per minute	fpm	≡ 1 ft/min	= 5.08Template:E m/s
inch per second	ips	≡ 1 in/s	= 2.54Template:E m/s
kilometre per hour	km/h	≡ 1 km/h	≈ 2.777 778Template:E m/s
foot per second	fps	≡ 1 ft/s	= 3.048Template:E m/s
mile per hour	mph	≡ 1 mi/h	= 0.447 04 m/s
knot	kn	≡ 1 NM/h = 1.852 km/h	≈ 0.514 444 m/s
knot (Admiralty)	kn	≡ 1 NM (Adm)/h = 1.853 184 km/h	≈ 0.514 773 m/s
mile per minute	mpm	≡ 1 mi/min	= 26.8224 m/s
mile per second	mps	≡ 1 mi/s = 1.609 344 km/s	= 1609.344 m/s
speed of light in vacuum	c	≡ 2.997 924 58Template:E m/s	= 2.997 924 58Template:E m/s
speed of sound in air	s	≡ 770 mph = 1230 km/h	≈ 344 m/s
mach	M	≡ 331 m/s	≈ 331 m/s

A velocity consists of a speed combined with a direction; the speed part of the velocity takes units of speed.

Acceleration

Acceleration
Name of unit	Symbol	Definition	Relation to SI units
metre per second squared (SI unit)	m/s²	≡ 1 m/s²	= 1 m/s²
foot per hour per second	fph/s	≡ 1 ft/(h·s)	≈ 8.466 667Template:E m/s²
inch per minute per second	ipm/s	≡ 1 in/(min·s)	≈ 4.233 333Template:E m/s²
foot per minute per second	fpm/s	≡ 1 ft/(min·s)	= 5.08Template:E m/s²
galileo	Gal	≡ 1 cm/s²	= 10⁻² m/s²
inch per second squared	ips²	≡ 1 in/s²	= 2.54Template:E m/s²
foot per second squared	fps²	≡ 1 ft/s²	= 3.048Template:E m/s²
mile per hour per second	mph/s	≡ 1 mi/(h·s)	= 4.4704Template:E m/s²
knot per second	kn/s	≡ 1 kn/s	≈ 5.144 444Template:E m/s²
standard gravity	g		≡ 9.806 65 m/s²
mile per minute per second	mpm/s	≡ 1 mi/(min·s)	= 26.8224 m/s²
mile per second squared	mps²	≡ 1 mi/s²	= 1.609 344Template:E m/s²

Force

Force
Name of unit	Symbol	Definition	Relation to SI units
newton (SI unit)	N	≡ kg·m/s²	= 1 N
atomic unit of force	au	≡ m_e·α²·c²/a₀	≈ 8.238 722 241Template:E N
dyne (cgs unit)	dyn	≡ g·cm/s²	= 10⁻⁵ N
milligrave-force, gravet-force	mGf; gf	≡ g × 1 g	= 9.806 65 mN
poundal	pdl	≡ 1 lb·ft/s²	= 0.138 254 954 376 N
ounce-force	ozf	≡ g × 1 oz	= 0.278 013 850 953 781 2 N
pound-force	lbf	≡ g × 1 lb	= 4.448 221 615 260 5 N
kilogram-force; kilopond; grave-force	kgf; kp; Gf	≡ g × 1 kg	= 9.806 65 N
sthene (mts unit)	sn	≡ 1 t·m/s²	= 1 Template:E N
kip; kip-force	kip; kipf; klbf	≡ g × 1000 lb	= 4.448 221 615 260 5 Template:E N
ton-force	tnf	≡ g × 1 sh tn	= 8.896 443 230 521 Template:E N

Pressure or mechanical stress

Pressure
Name of unit	Symbol	Definition	Relation to SI units
atmosphere (standard)	atm		≡ 101 325 Pa ^[8]
atmosphere (technical)	at	≡ 1 kgf/cm²	= 98.0665 Template:E Pa ^[8]
bar	bar		≡ 10⁵ Pa
barye (cgs unit)		≡ 1 dyn/cm²	= 0.1 Pa
centimetre of mercury	cmHg	≡ 13 595.1 kg/m³ × 1 cm × g	≈ 1.333 22 Template:E Pa ^[8]
centimetre of water (4 °C)	cmH₂O	≈ 999.972 kg/m³ × 1 cm × g	≈ 98.0638 Pa ^[8]
foot of mercury (conventional)	ftHg	≡ 13 595.1 kg/m³ × 1 ft × g	≈ 40.636 66 Template:E Pa ^[8]
foot of water (39.2 °F)	ftH₂O	≈ 999.972 kg/m³ × 1 ft × g	≈ 2.988 98 Template:E Pa ^[8]
inch of mercury (conventional)	inHg	≡ 13 595.1 kg/m³ × 1 in × g	≈ 3.386 389 Template:E Pa ^[8]
inch of water (39.2 °F)	inH₂O	≈ 999.972 kg/m³ × 1 in × g	≈ 249.082 Pa ^[8]
kilogram-force per square millimetre	kgf/mm²	≡ 1 kgf/mm²	= 9.806 65 Template:E Pa ^[8]
kip per square inch	ksi	≡ 1 kipf/sq in	≈ 6.894757 Template:E Pa ^[8]
millimetre of mercury	mmHg	≡ 13 595.1 kg/m³ × 1 mm × g ≈ 1 torr	≈ 133.322 4 Pa ^[8]
millimetre of water (3.98 °C)	mmH₂O	≈ 999.972 kg/m³ × 1 mm × g = 0.999972 kgf/m²	= 9.806 38 Pa
pascal (SI unit)	Pa	≡ N/m² = kg/(m·s²)	= 1 Pa ^[9]
pièze (mts unit)	pz	≡ 1000 kg/m·s²	= 1 Template:E Pa
pound per square foot	psf	≡ 1 lbf/ft²	≈ 47.880 25 Pa ^[8]
poundal per square foot	pdl/sq ft	≡ 1 pdl/sq ft	≈ 1.488 164 Pa ^[8]
pound per square inch	psi	≡ 1 lbf/in²	≈ 6.894 757 Template:E Pa ^[8]
short ton per square foot		≡ 1 sh tn × g / 1 sq ft	≈ 95.760 518 Template:E Pa
torr	torr	≡ 101 325/760 Pa	≈ 133.322 4 Pa ^[8]

Torque

Torque
Name of unit	Symbol	Definition	Relation to SI units
Newton metre (SI unit)	N·m	≡ N × m = kg·m²/s²	= 1 N·m
foot-poundal	ft pdl	≡ 1 lb·ft²/s²	= 4.214 011 009 380 48Template:E N·m
inch-pound force	in lbf	≡ g × 1 lb × 1 in	= 0.112 984 829 027 616 7 N·m
foot-pound force	ft lbf	≡ g × 1 lb × 1 ft	= 1.355 817 948 331 400 4 N·m

Energy

Energy
Name of unit	Symbol	Definition	Relation to SI units
joule (SI unit)	J	≡ m·N = W·s = V·A·s = kg·m²/s²	= 1 J
electronvolt	eV	≡ e × 1 V	≈ 1.602 176Template:E J
rydberg	Ry	≡ R_∞·ℎ·c	≈ 2.179 872Template:E J
hartree	E_h	≡ m_e·α²·c² (= 2 Ry)	≈ 4.359 744Template:E J
atomic unit of energy	au	≡ E_h	≈ 4.359 744Template:E J
erg (cgs unit)	erg	≡ 1 g·cm²/s²	= 10⁻⁷ J
foot-poundal	ft pdl	≡ 1 lb·ft²/s²	= 4.214 011 009 380 48Template:E J
cubic centimetre of atmosphere; standard cubic centimetre	cc atm; scc	≡ 1 atm × 1 cm³	= 0.101 325 J
inch-pound force	in lbf	≡ g × 1 lb × 1 in	= 0.112 984 829 027 616 7 J
foot-pound force	ft lbf	≡ g × 1 lb × 1 ft	= 1.355 817 948 331 400 4 J
calorie (20 °C)	cal_{20 °C}		≈ 4.1819 J
calorie (thermochemical)	cal_th		≡ 4.184 J
calorie (15 °C)	cal_{15 °C}		≡ 4.1855 J
calorie (International Table)	cal_IT		≡ 4.1868 J
calorie (mean)	cal_mean		≈ 4.190 02 J
calorie (3.98 °C)	cal_{3.98 °C}		≈ 4.2045 J
kilocalorie; large calorie	kcal; Cal	≡ 1000 cal_IT	= 4.1868 Template:E J
litre-atmosphere	l atm; sl	≡ 1 atm × 1 L	= 101.325 J
gallon-atmosphere (US)	US gal atm	≡ 1 atm × 1 gal (US)	= 383.556 849 013 8 J
gallon-atmosphere (imperial)	imp gal atm	≡ 1 atm × 1 gal (imp)	= 460.632 569 25 J
British thermal unit (thermochemical)	BTU_th		≈ 1.054 350 Template:E J
British thermal unit (ISO)	BTU_ISO		≡ 1.0545 Template:E J
British thermal unit (63 °F)	BTU_{63 °F}		≈ 1.0546 Template:E J
British thermal unit (60 °F)	BTU_{60 °F}		≈ 1.054 68 Template:E J
British thermal unit (59 °F)	BTU_{59 °F}		≡ 1.054 804 Template:E J
British thermal unit (International Table)	BTU_IT		= 1.055 055 852 62 Template:E J
British thermal unit (mean)	BTU_mean		≈ 1.055 87 Template:E J
British thermal unit (39 °F)	BTU_{39 °F}		≈ 1.059 67 Template:E J
Celsius heat unit (International Table)	CHU_IT	≡ 1 BTU_IT × 1 K/°R	= 1.899 100 534 716 Template:E J
cubic foot of atmosphere; standard cubic foot	cu ft atm; scf	≡ 1 atm × 1 ft³	= 2.869 204 480 934 4 Template:E J
cubic yard of atmosphere; standard cubic yard	cu yd atm; scy	≡ 1 atm × 1 yd³	= 77.468 520 985 228 8 Template:E J
cubic foot of natural gas		≡ 1000 BTU_IT	= 1.055 055 852 62 Template:E J
horsepower-hour	hp·h	≡ 1 hp × 1 h	= 2.684519537696172792 Template:E J
kilowatt-hour; Board of Trade Unit	kW·h; B.O.T.U.	≡ 1 kW × 1 h	= 3.6 Template:E J
thermie	th	≡ 1 Mcal_IT	= 4.1868 Template:E J
therm (U.S.)		≡ 100 000 BTU_{59 °F}	= 105.4804 Template:E J
therm (E.C.)		≡ 100 000 BTU_IT	= 105.505 585 262 Template:E J
ton of TNT	tTNT	≡ 1 Gcal_th	= 4.184 Template:E J
barrel of oil equivalent	bboe	≈ 5.8 MBTU_{59 °F}	≈ 6.12 Template:E J
ton of coal equivalent	TCE	≡ 7 Gcal_th	= 29.3076 Template:E J
ton of oil equivalent	TOE	≡ 10 Gcal_th	= 41.868 Template:E J
quad		≡ 10¹⁵ BTU_IT	= 1.055 055 852 62Template:E J

_{Subscript text^{Superscript text}}===Power===

Power
Name of unit	Symbol	Definition	Relation to SI units
watt (SI unit)	W	≡ J/s = N·m/s = kg·m²/s³	= 1 W
lusec	lusec	≡ 1 L·µmHg/s ^[10]	≈ 1.333Template:E W
foot-pound-force per hour	ft lbf/h	≡ 1 ft lbf/h	≈ 3.766 161Template:E W
atmosphere cubic centimetre per minute	atm ccm	≡ 1 atm × 1 cm³/min	= 1.688 75Template:E W
foot-pound-force per minute	ft lbf/min	≡ 1 ft lbf/min	= 2.259 696 580 552 334Template:E W
atmosphere–cubic centimetre per second	atm ccs	≡ 1 atm × 1 cm³/s	= 0.101 325 W
BTU (International Table) per hour	BTU_IT/h	≡ 1 BTU_IT/h	≈ 0.293 071 W
atmosphere–cubic foot per hour	atm cfh	≡ 1 atm × 1 cu ft/h	= 0.797 001 244 704 W
foot-pound-force per second	ft lbf/s	≡ 1 ft lbf/s	= 1.355 817 948 331 400 4 W
litre-atmosphere per minute	L·atm/min	≡ 1 atm × 1 L/min	= 1.688 75 W
calorie (International Table) per second	cal_IT/s	≡ 1 cal_IT/s	= 4.1868 W
BTU (International Table) per minute	BTU_IT/min	≡ 1 BTU_IT/min	≈ 17.584 264 W
atmosphere-cubic foot per minute	atm·cfm	≡ 1 atm × 1 cu ft/min	= 47.820 074 682 24 W
square foot equivalent direct radiation	sq ft EDR	≡ 240 BTU_IT/h	≈ 70.337 057 W
litre-atmosphere per second	L·atm/s	≡ 1 atm × 1 L/s	= 101.325 W
horsepower (metric)	hp	≡ 75 m kgf/s	= 735.498 75 W
horsepower (European electrical)	hp	≡ 75 kp·m/s	= 736 W
horsepower (Imperial mechanical)	hp	≡ 550 ft lbf/s	= 745.699 871 582 270 22 W
horsepower (Imperial electrical)	hp		≡ 746 W
ton of air conditioning		≡ 1 t × 1005 J/kg × 1 °R/K ÷ 10 min	≈ 844.2 W
poncelet	p	≡ 100 m kgf/s	= 980.665 W
BTU (International Table) per second	BTU_IT/s	≡ 1 BTU_IT/s	= 1.055 055 852 62Template:E W
atmosphere-cubic foot per second	atm cfs	≡ 1 atm × 1 cu ft/s	= 2.869 204 480 934 4Template:E W
ton of refrigeration (IT)		≡ 1 BTU_IT × 1 sh tn/lb ÷ 10 min/s	≈ 3.516 853Template:E W
ton of refrigeration (Imperial)		≡ 1 BTU_IT × 1 lng tn/lb ÷ 10 min/s	≈ 3.938 875Template:E W
boiler horsepower	bhp	≈ 34.5 lb/h × 970.3 BTU_IT/lb	≈ 9.810 657Template:E W

Angular momentum

Action, Angular momentum
Name of unit	Symbol	Definition	Relation to SI units
SI unit	J·s	≡ kg·m²/s	= 1 J·s
atomic unit of action	au	≡ ℏ = ℎ/2π	≈ 1.054 571 596Template:E J·s
cgs unit	erg·s		= 10⁻⁷ J·s

Electric current

Electric current
Name of unit	Symbol	Definition	Relation to SI units
ampere(SI base unit)	A		1 A
esu per second; statampere (cgs unit)	esu/s	≡ (0.1 A·m/s) /c	≈ 3.335 641Template:E A
electromagnetic unit; abampere (cgs unit)	abamp		≡ 10 A

Electric charge

Electric charge
Name of unit	Symbol	Definition	Relation to SI units
coulomb (SI unit)	C	≡ A·s	= 1 C
atomic unit of charge	au	≡ e	≈ 1.602 176 462Template:E C
statcoulomb; franklin; electrostatic unit (cgs unit)	statC; Fr; esu	≡ (0.1 A·m) /c	≈ 3.335 641Template:E C
abcoulomb; electromagnetic unit (cgs unit)	abC; emu		≡ 10 C
faraday	F	≡ 1 mol × N_A·e	≈ 96,485.3383 C

Electromotive force

Voltage, Electromotive force
Name of unit	Symbol	Definition	Relation to SI units
volt (SI unit)	V	≡ kg·m²/(A·s³)	= 1 V
abvolt (cgs unit)	abV		≡ 1Template:E V
statvolt (cgs unit)	statV	≡ c· (1 μJ/A·m)	= 299.792 458 V

Electrical resistance

Electrical resistance
Name of unit	Symbol	Definition	Relation to SI units
ohm (SI unit)	Ω	≡ V/A	= kg·m²/(A²·s³)

Inductance

Inductance
Name of unit	Symbol	Definition	Relation to SI units
henry (SI unit)	H	≡ (m²×kg)/(s²×A²) = (V×s)/A = (J×s²)/C² = (m²×kg)/C²	= 1 H

Dynamic viscosity

Dynamic viscosity
Name of unit	Symbol	Definition	Relation to SI units
pascal second (SI unit)	Pa·s	≡ N·s/m² , kg/(m·s)	= 1 Pa·s
poise (cgs unit)	P		≡ 10⁻¹ Pa·s

Kinematic viscosity

Kinematic viscosity
Name of unit	Symbol	Definition	Relation to SI units
SI unit	m²/s	≡ m²/s	= 1 m²/s
stokes (cgs unit)	St		≡ 10⁻⁴ m²/s

Information entropy

Information entropy
Name of unit	Symbol	Definition	Relation to SI units
SI unit	J/K	≡ J/K	= 1 J/K
nat; nip; nepit	nat	≡ k_B	= 1.3806505(23) × 10⁻²³ J/K
bit; shannon	bit; b; Sh	≡ ln(2) × k_B	= 9.569940(16) × 10⁻²⁴ J/K
ban; hartley	ban; Hart	≡ ln(10) × k_B	= 3.1790653(53) × 10⁻²³ J/K
nibble		≡ 4 bits	= 3.8279760(64) × 10⁻²³ J/K
byte	B	≡ 8 bits	= 7.655952(13) × 10⁻²³ J/K
kilobyte (decimal)	kB	≡ 1000 B	= 7.655952(13) × 10⁻²⁰ J/K
kilobyte (kibibyte)	KB; KiB	≡ 1024 B	= 7.839695(13) × 10⁻²⁰ J/K

Often, information entropy is measured in shannons, whereas the (discrete) storage space of digital devices is measured in bits. Thus, uncompressed redundant data occupy more than one bit of storage per shannon of information entropy. The multiples of a bit listed above are usually used with this meaning. Other times the bit is used as a measure of information entropy and is thus a synonym of shannon.

Temperature

Note: see Temperature conversion for more detail

Temperature
Name of unit	Symbol	Relation to SI units
kelvin (SI base unit)	K	1 K
degree Celsius	°C	[K] = [°C] + 273.15
degree Rankine	°R; °Ra	[K] = [°R] × 5⁄9
degree Fahrenheit	°F	[K] = ([°F] + 459.67) × 5⁄9
degree Delisle	°De	[K] = 373.15 − [°De] × 2⁄3
degree Newton	°N	[K] = [°N] × 100⁄33 + 273.15
degree Réaumur	°Ré	[K] = [°Ré] × 5⁄4 + 273.15
degree Rømer	°Rø	[K] = ([°Rø] − 7.5) × 40⁄21 + 273.15

Radioactivity

Radioactivity
Name of unit	Symbol	Definition	Relation to SI units
Becquerel (SI base unit)	Bq	≡ disintegration per second s^-1	= 1 Bq
Rutherford	rd	≡ 1 MBq	= 1 * 10⁶ Bq
curie	Ci	≡ 3.7 * 10¹⁰ Bq	= 3.7 * 10¹⁰ Bq^[11]

Radioactivity - absorbed dose

Radioactivity - absorbed dose
Name of unit	Symbol	Definition	Relation to SI units
Gray (SI base unit)	Gy	≡ 1gy = 1J/s = 1m²s^-2	= 1 Gy
Rad	rad	≡ 0.01 Gy	= 0.01 Gy

Radioactivity - equivalent dose

Radioactivity - equivalent dose
Name of unit	Symbol	Definition	Relation to SI units
Sievert (SI base unit)	Sv		= 1 Sv
Röntgen equivalent man	rem	≡ 0.01 Sv	= 0.01 Sv

Software tools

Home and office computers come with converters in bundled spreadsheet applications or can access free converters via the Internet. Units and measurements can be easily converted using these tools, but only if the units are explicitly defined and the conversion is compatible (e.g., cmHg to kPa).

Free conversion software

Units (Unix program) — a popular command-line utility.

General commercial sources of converters

Advanced electronic calculators have unit-conversion functionality.
Spreadsheet programs usually provide conversion functions or formulas or the user can write their own.
Commercial mathematical, scientific and technical applications often include converters.

References

↑ "NIST Reference on Constants, Units, and Uncertainty."(2006). National Institute of Standards and Technology. Accessed 22 February 2008.
↑ ^2.0 ^2.1 National Bureau of Standards. (June 30, 1959). Refinement of values for the yard and the pound. Federal Register, viewed September 20, 2006 at National Geodetic Survey web site.
↑ International System of Units, 8th ed. (2006), Bureau International des Poids et Mesures, Section 4.1 Table 8.
↑ P. Kenneth Seidelmann, Ed. (1992). Explanatory Supplement to the Astronomical Almanac. Sausalito, CA: University Science Books. p. 716 and s.v. parsec in Glossary.
↑ Barry N. Taylor, Ed.,NIST Special Publication 330: The International System of Units (SI) (2001 Edition), Washington: U.S. Government Printing Office, 43,"The 12th Conference Generale des Poids et Mesures (CGPM)…declares that the word “liter” may be employed as a special name for the cubic decimeter".
↑ The Swiss Federal Office for Metrology gives Zentner on a German language web page[1] and quintal on the English translation of that page[2]; the unit is marked "spécifiquement suisse !"
↑ Rowlett, Russ. A Dictionary of Units of Measurement. Viewed October 14, 2006 at http://www.unc.edu/~rowlett/units/dictZ.html
↑ ^8.00 ^8.01 ^8.02 ^8.03 ^8.04 ^8.05 ^8.06 ^8.07 ^8.08 ^8.09 ^8.10 ^8.11 ^8.12 ^8.13 ^8.14 Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units (SI) (NIST Special Publication 811), Washington, DC: U.S. Government Printing Office, pp. 57–68.
↑ Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units (SI) (NIST Special Publication 811), Washington, DC: U.S. Government Printing Office, p. 5.
↑ Russ Rowlett. (2005). How Many: A Dictionary of Units of Measure. Viewed 5 November 2006 at http://www.unc.edu/~rowlett/units/
↑ Ambler Thompson & Barry N. Taylor. (2008). Guide for the Use of the International System of Units (SI). (Special Publication 811. Gaithersburg, MD: National Institute of Standards and Technology. p. 10.

Klein, Herbert. 1988. The science of measurement: A historical survey. New York: Dover Publications.

External links

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[1] "NIST Reference on Constants, Units, and Uncertainty."(2006). National Institute of Standards and Technology. Accessed 22 February 2008.

[nbs-2] 2.0 ^2.1 National Bureau of Standards. (June 30, 1959). Refinement of values for the yard and the pound. Federal Register, viewed September 20, 2006 at National Geodetic Survey web site.

[Table8-3] International System of Units, 8th ed. (2006), Bureau International des Poids et Mesures, Section 4.1 Table 8.

[Seidelmann-4] P. Kenneth Seidelmann, Ed. (1992). Explanatory Supplement to the Astronomical Almanac. Sausalito, CA: University Science Books. p. 716 and s.v. parsec in Glossary.

[specpub330-5] Barry N. Taylor, Ed.,NIST Special Publication 330: The International System of Units (SI) (2001 Edition), Washington: U.S. Government Printing Office, 43,"The 12th Conference Generale des Poids et Mesures (CGPM)…declares that the word “liter” may be employed as a special name for the cubic decimeter".

[6] The Swiss Federal Office for Metrology gives Zentner on a German language web page[1] and quintal on the English translation of that page[2]; the unit is marked "spécifiquement suisse !"

[7] Rowlett, Russ. A Dictionary of Units of Measurement. Viewed October 14, 2006 at http://www.unc.edu/~rowlett/units/dictZ.html

[press811-8] 8.00 ^8.01 ^8.02 ^8.03 ^8.04 ^8.05 ^8.06 ^8.07 ^8.08 ^8.09 ^8.10 ^8.11 ^8.12 ^8.13 ^8.14 Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units (SI) (NIST Special Publication 811), Washington, DC: U.S. Government Printing Office, pp. 57–68.

[9] Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units (SI) (NIST Special Publication 811), Washington, DC: U.S. Government Printing Office, p. 5.

[10] Russ Rowlett. (2005). How Many: A Dictionary of Units of Measure. Viewed 5 November 2006 at http://www.unc.edu/~rowlett/units/

[11] Ambler Thompson & Barry N. Taylor. (2008). Guide for the Use of the International System of Units (SI). (Special Publication 811. Gaithersburg, MD: National Institute of Standards and Technology. p. 10.

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