Tables of conversion factors

Legend

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

Length

Length, l
Name of unit	Symbol	Definition	Relation to SI units
angstrom	Å		≡ 1.000×10⁻¹⁰ m = 0.1 nm
astronomical unit	AU	Mean distance from Earth to the Sun	= 149 597 870.691 ± 0.030 km
atomic unit of length	au	≡ a₀	≈ 5.291 772 083×10⁻¹¹ ± 19×10⁻²⁰ m
barley corn		≡ 1/3 in	≈ 8.466 667 mm
Bohr radius	a₀; b	≡ α/(4πR_∞)	≈ 5.291 772 083×10⁻¹¹ ± 19×10⁻²⁰ m
cable length (Imperial)		≡ 608 ft	= 185.3184 m
cable length (International)		≡ 1/10 NM	= 185.2 m
cable length (U.S.)		≡ 720 ft	= 219.456 m
calibre	cal	≡ 1 in	= 25.4 mm
chain (Gunter's; Surveyor's)	ch	≡ 66 ft	= 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 NM	= 1.852 m
fermi	fm	≡ 1.000×10⁻¹⁵ m	= 1.000×10⁻¹⁵ m
finger		≡ 7/8 in	= 22.225 mm
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	≡ 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 ^[1]	≈ 0.304 800 610 m
furlong	fur	≡ 660 ft	= 201.168 m
geographical mile	mi	≡ 6082 ft	= 1853.7936 m
hand		≡ 4 in	= 0.1016 m
inch	in	≡ 1/36 yd	= 25.4 mm
league	lea	≡ 3 mi	= 4828.032 m
light-day		≡ 24 light-hours	= 2.590 206 837 12×10¹³ m
light-hour		≡ 60 light-minutes	= 1.079 252 848 8×10¹² m
light-minute		≡ 60 light-seconds	= 1.798 754 748×10¹⁰ m
light-second			≡ 2.997 924 58×10⁸ m
light-year	l.y.	≡ c₀ × 86 400 × 365.25	= 9.460 730 472 580 8×10¹⁵ m
line	ln	≡ 1/12 in (Klein 1988, 63)	≈ 2.116 667 mm
link (Gunter's; Surveyor's)	lnk	≡ 1/100 ch	= 0.201 168 m
link (Ramsden's; Engineer's)	lnk	≡ 1 ft	= 0.3048 m
metre (SI base unit)	m	≡ 1 m	= 1 m
mickey		≡ 1/200 in	= 1.27×10⁻⁴ m
micron	µ		≡ 1.000×10⁻⁶ m
mil; thou	mil	≡ 1.000×10⁻³ in	= 2.54×10⁻⁵ 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	= 57.15 mm
nautical league	NL; nl	≡ 3 NM	= 5556 m
nautical mile	NM; nm		≡ 1852 m
nautical mile (Admiralty)	NM (Adm); nm (Adm)	≡ 6080 ft	= 1853.184 m
pace		≡ 2.5 ft	= 0.762 m
palm		≡ 3 in	= 76.2 mm
parsec	pc	≈ 180 × 60 × 60/π AU ≈ 206 264.806 25 AU = 3.261 563 776 9 ± 6 ×10⁻¹⁰ light-years	= 3.085 677 581 3×10¹⁶ ± 6×10⁶ m
point (ATA)	pt	≡ 0.013837 in	= 0.351 459 8 mm
point (Didot; European)	pt		≡ 0.376 065 mm
point (metric)	pt	≡ 3/8 mm	= 0.375 mm
point (PostScript)	pt	≡ 1/72 in	≈ 0.352 778 mm
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^{[citation needed]}	S	≡ 10¹² m	= 1 Tm
stick		≡ 2 in	= 50.8 mm
stigma; pm		≡ 1.000×10⁻¹² m	≡ 1.000×10⁻¹² m
telegraph mile	mi	≡ 6087 ft	= 1855.3176 m
twip	twp	≡ 1/1440 in	≈ 1.763 889×10⁻⁵ m
x unit; siegbahn	xu		≈ 1.0021×10⁻¹³ m
yard (International)	yd	≡3 ft ≡ 0.9144 m ^[1]	= 0.9144 m

Area

Area, A
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 96×10⁷ m²
board	bd	≡ 1 in × 1 ft	= 7.741 92×10⁻³ 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 in²	≈ 5.067 075×10⁻⁴ m²
circular mil; circular thou	circ mil	≡ π/4 mil²	≈ 5.067 075×10⁻¹⁰ m²
cord		≡ 192 bd	= 1.486 448 64 m²
dunam		≡ 1000 m²	= 1000 m²
hectare	ha	≡ 10 000 m²	= 0.01 km²
hide		≡ 100 ac	= 4.046 856 422 4×10⁵ m²
rood	ro	≡ ¼ ac	= 1011.714 105 6 m²
square chain	sq ch	≡ 1 ch²	= 404.685 642 24 m²
square foot	sq ft	≡ 1 ft²	= 9.290 304×10⁻² m²
square inch	sq in	≡ 1 in²	= 6.4516×10⁻⁴ m²
square kilometre	km²	≡ 1 km²	= 10⁶ m²
square link	sq lnk	≡ 1 lnk²	= 4.046 856 422 4×10⁻² m²
square metre (SI unit)	m²	≡ 1 m × 1 m	= 1 m²
square mil; square thou	sq mil	≡ 1 mil²	= 6.4516×10⁻¹⁰ m²
square mile; section	sq mi	≡ 1 mi²	= 2.589 988 110 336×10⁶ m²
square rod/pole/perch	sq rd	≡ 1 rd²	= 25.292 852 64 m²
square U.S. Survey mile	sq mi	≡ 1 mi (US)²	≈ 2.589 998×10⁶ m²
square yard	sq yd	≡ 1 yd²	= 0.836 127 36 m²
stremma		≡ 1000 m²	= 1000 m²
township		≡ 36 sq mi (US)	≈ 9.323 994×10⁷ m²
yardland		≡ 30 ac	= 1.214 056 926 72×10⁵ m²

Volume

Volume, V
Name of unit	Symbol	Definition	Relation to SI units
cubic metre (SI unit)	m³	≡ 1 m × 1 m × 1 m
litre	L		≡ 1 dm³
lambda	λ	≡ 1 mm³	= 1 μL
drop (metric)		≡ 1/20 mL	= 0.05 mL
minim (Imperial)	min	≡ 1/480 fl oz (Imp) = 1/60 fl dr (Imp)	≈ 0.059 193 880 208 333 mL
minim (U.S.)	min	≡ 1/480 US fl oz = 1/60 US fl dr	= 0.061 611 519 921 875 mL
drop (U.S.) (alt)	gtt	≡ 1/456 US fl oz	≈ 0.064 854 231 mL
drop (Imperial) (alt)	gtt	≡ 1/1824 gi (Imp)	≈ 0.077 886 684 mL
drop (U.S.)	gtt	≡ 1/360 US fl oz	= 0.082 148 693 229 1(6) mL
drop (medical)		≡ 1/12 mL	= 0.08(3) mL
drop (Imperial)	gtt	≡ 1/288 fl oz (Imp)	= 0.098 656 467 013 (8) mL
dash (U.S.)		≡ 1/96 US fl oz = ½ US pinch	= 0.308 057 599 609 375 mL
dash (Imperial)		≡ 1/384 gi (Imp) = ½ pinch (Imp)	= 0.369 961 751 302 08(3) mL
pinch (U.S.)		≡ 1/48 US fl oz = ⅛ US tsp	= 0.616 115 199 218 75 mL
pinch (Imperial)		≡ 1/192 gi (Imp) = ⅛ tsp (Imp)	= 0.739 923 502 604 1(6) mL
fluid scruple (Imperial)	fl s	≡ 1/24 fl oz (Imp)	= 1.183 877 604 1(6) mL
fluid drachm (Imperial)	fl dr	≡ ⅛ fl oz (Imp)	= 3.551 632 812 5 mL
fluid dram (U.S.); U.S. fluidram	fl dr	≡ ⅛ US fl oz	= 3.696 691 195 312 5 mL
teaspoon (Canadian)	tsp	≡ 1/6 fl oz (Imp)	≈ 4.735 510 416 667 mL
teaspoon (U.S.)	tsp	≡ 1/6 US fl oz	= 4.928 921 595 mL
teaspoon (metric)			≡ 5 mL
teaspoon (Imperial)	tsp	≡ 1/24 gi (Imp)	= 5.919 388 020 8(3) mL
dessertspoon (Imperial)		≡ 1/12 gi (Imp)	= 11.838 776 041 (6) mL
tablespoon (Canadian)	tbsp	≡ ½ fl oz (Imp)	= 14.206 531 25 mL
tablespoon (U.S.)	tbsp	≡ ½ US fl oz	= 14.786 764 782 5 mL
tablespoon (metric)			≡ 15 mL
cubic inch	cu in	≡ 1 in³	= 16.387 064 mL
tablespoon (Imperial)	tbsp	≡ 5/8 fl oz (Imp)	= 17.758 164 062 5 mL
pony		≡ 3/4 US fl oz	= 22.180 147 171 875 mL
fluid ounce (Imperial)	fl oz (Imp)	≡ 1/160 gal (Imp)	= 28.413 062 5 mL
fluid ounce (U.S.)	fl oz (US)	≡ 1/128 gal (US)	= 29.573 529 562 5 mL
shot		≡ 1 US fl oz	= 29.573 529 562 5 mL
jigger		≡ 1½ US fl oz	= 44.360 294 343 75 mL
gill (U.S.)	gi (US)	≡ 4 US fl oz	= 118.294 118 25 mL
gill (Imperial); Noggin	gi (Imp); nog	≡ 5 fl oz (Imp)	= 142.065 312 5 mL
cup (Canadian)	c (CA)	≡ 8 fl oz (Imp)	= 227.3045 mL
cup (U.S.)	c (US)	≡ 8 US fl oz ≡ 1/16 gal (US)	= 236.588 236 5 mL
cup (metric)	c		≡ 250 mL
breakfast cup		≡ 10 fl oz (Imp)	= 284.130 625 mL
pint (U.S. fluid)	pt (US fl)	≡ ⅛ gal (US)	= 473.176 473 mL
pint (U.S. dry)	pt (US dry)	≡ 1/64 bu (US lvl) ≡ ⅛ gal (US dry)	= 0.550 610 471 357 5 L
pint (Imperial)	pt (Imp)	≡ ⅛ gal (Imp)	= 0.568 261 25 L
fifth		≡ 1/5 US gal	= 0.757 082 356 8 L
quart (U.S. fluid)	qt (US)	≡ ¼ gal (US fl)	= 0.946 352 946 L
quart (U.S. dry)	qt (US)	≡ 1/32 bu (US lvl) = ¼ gal (US dry)	= 1.101 220 942 715 L
quart (Imperial)	qt (Imp)	≡ ¼ gal (Imp)	= 1.136 522 5 L
pottle; quartern		≡ ½ gal (Imp) = 80 fl oz (Imp)	= 2.273 045 L
board-foot	fbm	≡ 144 cu in	= 2.359 737 216 L
gallon (U.S. fluid; Wine)	gal (US)	≡ 231 cu in	= 3.785 411 784 L
gallon (U.S. dry)	gal (US)	≡ ⅛ bu (US lvl)	= 4.404 883 770 86 L
gallon (Imperial)	gal (Imp)	≡	= 4.546 09 L
beer gallon	beer gal	≡ 282 cu in	= 4.621 152 048 L
peck (U.S. dry)	pk	≡ ¼ US lvl bu	= 8.809 767 541 72 L
peck (Imperial)	pk	≡ 2 gal (Imp)	= 9.092 18 L
bucket (Imperial)	bkt	≡ 4 gal (Imp)	= 18.184 36 L
timber foot		≡ 1 cu ft	= 28.316 846 592 L
cubic foot	cu ft	≡ 1 ft × 1 ft × 1 ft	= 28.316 846 592 L
firkin		≡ 9 gal (US)	= 34.068 706 056 L
bushel (U.S. dry level)	bu (US lvl)	≡ 2150.42 cu in	= 35.239 070 166 88 L
bushel (Imperial)	bu (Imp)	≡ 8 gal (Imp)	= 36.368 72 L
bushel (U.S. dry heaped)	bu (US)	≡ 1 ¼ bu (US lvl)	= 44.048 837 708 6 L
strike (U.S.)		≡ 2 bu (US lvl)	= 70.478 140 333 76 L
strike (Imperial)		≡ 2 bu (Imp)	= 72.737 44 L
kilderkin		≡ 18 gal (Imp)	= 81.829 62 L
sack (U.S.)		≡ 3 bu (US lvl)	= 105.717 210 500 64 L
sack (Imperial); bag		≡ 3 bu (Imp)	= 109.106 16 L
barrel (U.S. dry)	bl (US)	≡ 105 qt (US) = 105/32 bu (US lvl)	= 115.628 198 985 075 L
barrel (U.S. fluid)	fl bl (US)	≡ 31½ gal (US)	= 119.240 471 196 L
coomb		≡ 4 bu (Imp)	= 145.474 88 L
barrel (petroleum)	bl	≡ 42 gal (US)	= 158.987 294 928 L
barrel (Imperial)	bl (Imp)	≡ 36 gal (Imp)	= 163.659 24 L
hogshead (U.S.)	hhd (US)	≡ 2 fl bl (US)	= 238.480 942 392 L
seam		≡ 8 bu (US lvl)	= 281.912 561 335 04 L
quarter; pail		≡ 8 bu (Imp)	= 290.949 76 L
hogshead (Imperial)	hhd (Imp)	≡ 2 bl (Imp)	= 327.318 48 L
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
acre-foot		≡ 1 ac × 1 ft	= 1233.481 837 547 52 m³
cubic mile	cu mi	≡ 1 mi³	= 4.168 181 825 440 579 584 km³

Angle

Angle
Name of unit	Symbol	Definition	Relation to SI units
radian (SI unit)	rad		≡ 1 rad
centesimal second of arc	"	≡ 1 gr/10000	≈ 1.570 796 µrad
arcsecond	"	≡ 1°/3600	≈ 4.848 137 µrad
centesimal minute of arc	'	≡ 1 gr/100	≈ 0.157 080 mrad
minute of arc	'	≡ 1°/60	≈ 0.290 888 mrad
angular mil	µ	≡ 2π/6400 rad	≈ 0.981 748 mrad
grad; gradian; gon	gr	≡ 2π/400 rad = 0.9°	≈ 15.707 963 mrad
degree (of arc)	°	≡ π/180 rad	≈ 17.453 293 mrad
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

Mass, m
Name of unit	Symbol	Definition	Relation to SI units	Relation to avoirdupois units
kilogram, grave	kg; G		(SI base unit)
electron rest mass	m_e		≈ 9.109 381 88×10⁻³¹ ± 72×10⁻³⁹ kg
atomic unit of mass	au	≡ m_e	≈ 9.109 381 88×10⁻³¹ ± 72×10⁻³⁹ kg
unified atomic mass unit	amu		≈ 1.660 538 73×10⁻²⁷ ± 13×10⁻³⁵ kg
dalton	Da		≈ 1.660 902 10×10⁻²⁷ ± 13×10⁻³⁵ kg
gamma	γ		≡ 1 μg
point		≡ 1/100 kt (metric)	= 2 mg
mite		≡ 1/20 gr	= 3.239 945 5 mg
mite (metric)		≡ 1/20 g	= 50 mg
grain	gr		≡ 64.798 91 mg
crith			≈ 89.9349 mg
carat (metric)	kt		≡ 200 mg
carat	kt	≡ 3 1/6 gr	≈ 205.196 548 333 mg
sheet		≡ 1/700 lb av	= 647.9891 mg
scruple (avoirdupois)	s av	≡ 20 gr	= 1.295 978 2 g
pennyweight	dwt; pwt	≡ 1/20 oz t	= 1.555 173 84 g
dram (avoirdupois)	dr av	≡ 27 11/32 gr	= 1.771 845 195 312 5 g
dram (apothecary; troy)	dr t	≡ 60 gr	= 3.887 934 6 g
hyl (CGS unit)		≡ 1 gee × 1 g × 1 s²/m	= 9.806 65 g
ounce (avoirdupois)	oz av	≡ 1/16 lb	= 28.349 523 125 g
assay ton (short)	AT	≡ 1 mg × 1 sh tn ÷ 1 oz t	≈ 29.166 667 g
ounce (apothecary; troy)	oz t	≡ 1/12 lb t	= 31.103 476 8 g
assay ton (long)	AT	≡ 1 mg × 1 long tn ÷ 1 oz t	≈ 32.666 667 g
mark		≡ 8 oz t	= 248.827 814 4 g
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)			≡ 500 g
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	= 114.305 277 24 kg (variants exist)
long quarter		≡ ¼ long tn	= 254.011 727 2 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 ^[2] and ^[3]. 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	s		(SI base unit)
Planck time		≡ √(G ℏ/c⁵)	≈ 1.351 211 818×10⁻⁴³ s
atomic unit of time	au	≡ a₀/(α·c)	≈ 2.418 884 254×10⁻¹⁷ s
svedberg	S	≡ 10⁻¹³ s	= 100 fs
shake		≡ 10⁻⁸ s	= 10 ns
sigma		≡ 10⁻⁶ s	= 1 μs
jiffy		≡ 1/60 s	≈ 16.666 667 ms
jiffy (alternate)		≡ 1/100 s	≈ 10 ms
helek		≡ 1/1080 h	≈ 3.333333 s
minute	min		≡ 60 s
moment		≡ 90 s	≡ 90 s
ke(traditional)		≡ 1/100 d	≡ 864 s
quarter (of an h)	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 or y	≡ 365 d	= 31 536 000 s
year (Gregorian)	a or y	≡ 365.2425 d	= 31 556 952 s
year (Julian)	a or y	≡ 365.25 d	= 31 557 600 s
sidereal year	a or y	≡ 365.256363 d	= 31 558 149.76 s
Olympiad		≡ 4 a of 365 d	= 1.2614×10⁸ s
lustre; lustrum		≡ 5 a of 365 d	= 1.5768×10⁸ s
octaeteris		≡ 8 a of 365 d	= 2.522 88×10⁸ s
decade		≡ 10 a of 365 d	= 3.1536×10⁸ s
enneadecaeteris; Metonic cycle		≡ 110 mo (hollow) + 125 mo (full) = 19 a of 365 d	= 5.996 16×10⁸ s
Callippic cycle		≡ 441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d	= 2.398 377 6×10⁹ s
century (Calendar)		≡ 100 a of 365 d	= 3.1536×10⁹ s
century (Julian)		≡ 100 a of 365.25 d	= 3.155 76×10⁹ s
Hipparchic cycle		≡ 4 Callippic cycles - 1 d	= 9.593 424×10⁹ s
millennium (Calendar)		≡ 1000 a of 365 d	= 3.1536×10¹⁰ s
millennium (Gregorian)		≡ 1000 a of 365.2425 d	= 3.155 695 2×10¹⁰ s
millennium (Julian)		≡ 1000 a of 365.25 d	= 3.155 76×10¹⁰ s
Sothic cycle		≡ 1461 a of 365 d	= 4.607 409 6×10¹⁰ s

Speed

Speed, v
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	≈ 8.466 667×10⁻⁵ m/s
furlong per fortnight		≡ ½ fur/wk	≈ 1.663 095×10⁻⁴ m/s
inch per minute	ipm	≡ 1 in/min	≈ 4.23 333×10⁻⁴ m/s
foot per minute	fpm	≡ 1 ft/min	= 5.08×10⁻³ m/s
inch per second	ips	≡ 1 in/s	= 2.54×10⁻² m/s
kilometre per hour	km/h	≡ 1 km/h	≈ 2.777 778×10⁻¹ m/s
foot per second	fps	≡ 1 ft/s	= 3.048×10⁻¹ 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
speed of light in vacuum	c	≡ 2.997 924 58×10⁸ m/s

Acceleration

Acceleration, a
Name of unit	Symbol	Definition	Relation to SI units
metre per second squared (SI unit)	m/s²		≡ 1 m/s²
foot per hour per second	fph/s	≡ 1 ft/h·s	≈ 8.466 667×10⁻⁵ m/s²
inch per minute per second	ipm/s	≡ 1 in/min·s	≈ 4.233 333×10⁻⁴ m/s²
foot per minute per second	fpm/s	≡ 1 ft/min·s	= 5.08×10⁻³ m/s²
galileo	Gal	≡ 1 cm/s²	= 10⁻² m/s²
inch per second squared	ips²	≡ 1 in/s²	= 2.54×10⁻² m/s²
foot per second squared	fps²	≡ 1 ft/s²	= 3.048×10⁻¹ m/s²
mile per hour per second	mph/s	≡ 1 mi/h·s	= 4.4704×10⁻¹ m/s²
knot per second	kn/s	≡ 1 kn/s	≈ 5.144 444×10⁻¹ 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	= 1.609 344×10³ m/s²

Force

Force, F
Name of unit	Symbol	Definition	Relation to SI units
newton (SI unit)	N	≡ kg·m/s²
atomic unit of force	au	≡ m_e·α²·c²/a₀	≈ 8.238 722 241×10⁻⁸ N
dyne (cgs unit)	dyn	≡ g·cm/s²	ljm = 10⁻⁵ N
milligrave-force, gravet	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 kN
kip; kip-force	kip; kipf; klbf	≡ g × 1000 lb	= 4.448 221 615 260 5 kN
ton-force	tnf	≡ g × 1 sh tn	= 8.896 443 230 521 kN

Pressure or mechanical stress

Pressure, p (lower case)
Name of unit	Symbol	Definition	Relation to SI units
pascal (SI unit)	Pa	≡ N/m²	= kg/(m·s²)
barye (cgs unit)		≡ 1 dyn/cm²	= 0.1 Pa
poundal per square foot	pdl/sq ft	≡ 1 pdl/sq ft	≈ 1.488 164 Pa
millimetre of water (3.98 °C)	mmH₂O	≈ 999.972 kg/m³ × 1 mm × g	= 9.806 38 Pa (= 0.999972 kgf/m²)
pound per square foot	psf	≡ 1 lb/sq ft × g	≈ 47.880 259 Pa
centimetre of water (3.98 °C)	cmH₂O	≈ 999.972 kg/m³ × 1 cm × g	= 98.0638 Pa
torr	torr	≡ 101 325/760 Pa	≈ 133.322 368 4 Pa
millimetre of mercury	mmHg	≡ 13 595.1 kg/m³ × 1 mm × g ≈ 1 torr	= 133.322 387 415 Pa
inch of water (3.98 °C)	inH₂O	≈ 999.972 kg/m³ × 1 in × g	= 249.082 Pa
pièze (mts unit)	pz	≡ 1000 kg/m·s²	= 1 kPa
centimetre of mercury	cmHg	≡ 13 595.1 kg/m³ × 1 cm × g	= 1.333 223 874 15 kPa
foot of water (3.98 °C)	ftH₂O	≈ 999.972 kg/m³ × 1 ft × g	= 2.988 98 kPa
inch of mercury	inHg	≡ 13 595.1 kg/m³ × 1 in × g	= 3.386 388 640 341 kPa
pound per square inch	psi	≡ 1 lb × g / 1 sq in	≈ 6.894 757 kPa
foot of mercury	ftHg	≡ 13 595.1 kg/m³ × 1 ft × g	= 40.636 663 684 091 9 kPa
short ton per square foot		≡ 1 sh tn × g / 1 sq ft	≈ 95.760 518 kPa
atmosphere (technical)	atm	≡ 1 kgf/cm²	= 98.0665 kPa
bar	bar		≡ 10⁵ Pa
atmosphere (standard)	atm		≡ 101 325 Pa
kip per square inch	ksi	≡ 1 kipf/sq in	≈ 6.894757 MPa
kilogram-force per square millimetre	kgf/mm²	≡ 1 kgf/mm²	= 9.806 65 MPa

Energy, work, or heat

Energy, E
Name of unit	Symbol	Definition	Relation to SI units
joule (SI unit)	J	≡ N·m = W·s = V·A·s	= kg·m²/s²
electronvolt	eV	≡ e × 1 V	≈ 1.602 176×10⁻¹⁹ J
rydberg	Ry	≡ R_∞·ℎ·c	≈ 2.179 872×10⁻¹⁸ J
hartree	E_h	≡ m_e·α²·c² (= 2 Ry)	≈ 4.359 744×10⁻¹⁸ J
atomic unit of energy	au	≡ E_h ≈ 4.359 744×10⁻¹⁸ 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 48×10⁻² 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
litre-atmosphere	l atm; sl	≡ 1 atm × 1 L	= 101.325 J
gallon-atmosphere (U.S.)	US gal atm	≡ 1 atm × 1 gal (US)	= 383.556 849 013 8 J
gallon-atmosphere (Imperial)	US gal atm	≡ 1 atm × 1 gal (Imp)	= 460.632 569 25 J
British thermal unit (thermochemical)	BTU_th	≡ 1 lb/g × 1 cal_th × 1 °F/°C = 9.489 152 380 4 ÷ 9 kJ	≈ 1.054 350 kJ
British thermal unit (ISO)	BTU_ISO		≡ 1.0545 kJ
British thermal unit (63 °F)	BTU_{63 °F}		≈ 1.0546 kJ
British thermal unit (60 °F)	BTU_{60 °F}		≈ 1.054 68 kJ
British thermal unit (59 °F)	BTU_{59 °F}		≡ 1.054 804 kJ
British thermal unit (International Table)	BTU_IT	≡ 1 lb/g × 1 cal_IT × 1 °F/°C	= 1.055 055 852 62 kJ
British thermal unit (mean)	BTU_mean		≈ 1.055 87 kJ
British thermal unit (39 °F)	BTU_{39 °F}		≈ 1.059 67 kJ
Celsius heat unit (International Table)	CHU_IT	≡ 1 BTU_IT × 1 °C/°F	= 1.899 100 534 716 kJ
cubic foot of atmosphere; standard cubic foot	cu ft atm; scf	≡ 1 atm × 1 ft³	= 2.869 204 480 934 4 kJ
kilocalorie; large calorie	kcal; Cal	≡ 1000 cal_IT	= 4.1868 kJ
cubic yard of atmosphere; standard cubic yard	cu yd atm; scy	≡ 1 atm × 1 yd³	= 77.468 520 985 228 8 kJ
cubic foot of natural gas		≡ 1000 BTU_IT	= 1.055 055 852 62 MJ
horsepower-hour	hp·h	≡ 1 hp × 1 h	= 2.6845 MJ
kilowatt-hour; Board of Trade Unit	kW·h; B.O.T.U.	≡ 1 kW × 1 h	= 3.6 MJ
thermie	th	≡ 1 Mcal_IT	= 4.1868 MJ
therm (U.S.)		≡ 100 000 BTU_{59 °F}	= 105.4804 MJ
therm (E.C.)		≡ 100 000 BTU_IT	= 105.505 585 262 MJ
ton of TNT	tTNT	≡ 1 Gcal_th	= 4.184 GJ
barrel of oil equivalent	bboe	≈ 5.8 MBTU_{59 °F}	≈ 6.12 GJ
ton of coal equivalent	TCE	≡ 7 Gcal_th	= 29.3076 GJ
ton of oil equivalent	TOE	≡ 10 Gcal_th	= 41.868 GJ
quad		≡ 10¹⁵ BTU_IT	= 1.055 055 852 62 EJ

Power

Power, P
Name of unit	Symbol	Definition	Relation to SI units
watt (SI unit)	W	≡ J/s = N·m/s	= kg·m²/s³
lusec	lusec	≡ 1 L·µmHg/s ^[4]	≈ 1.333×10⁻⁴ W
foot-pound-force per hour	ft lbf/h	≡ 1 ft lbf/h	≈ 3.766 161×10⁻⁴ W
atmosphere cubic centimetre per minute	atm ccm	≡ 1 atm × 1 cm³/min	= 1.688 75×10⁻³ W
foot-pound-force per minute	ft lbf/min	≡ 1 ft lbf/min	= 2.259 696 580 552 334×10⁻² 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 °F/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 62×10³ W
atmosphere-cubic foot per second	atm cfs	≡ 1 atm × 1 cu ft/s	= 2.869 204 480 934 4×10³ W
ton of refrigeration (IT)		≡ 1 BTU_IT × 1 sh tn/lb ÷ 10 min/s	≈ 3.516 853×10³ W
ton of refrigeration (Imperial)		≡ 1 BTU_IT × 1 lng tn/lb ÷ 10 min/s	≈ 3.938 875×10³ W
boiler horsepower	bhp	≈ 34.5 lb/h × 970.3 BTU_IT/lb	≈ 9.810 657×10³ W

Angular momentum

Action, Angular momentum, L, J
Name of unit	Symbol	Definition	Relation to SI units
SI unit	J·s		≡ kg·m²/s
atomic unit of action	au	≡ ℏ = ℎ/2π	≈ 1.054 571 596×10⁻³⁴ J·s
cgs unit	erg·s		= 10⁻⁷ J·s

Electric current

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

Electric charge

Electromotive force

Voltage, Electromotive force, U
Name of unit	Symbol	Definition	Relation to SI units
volt (SI unit)	V		≡ kg·m²/(A·s³)
abvolt (cgs unit)	abV		≡ 1×10⁻⁸ V
statvolt (cgs unit)	statV	≡ c· (1 μJ/A·m)	= 299.792 458 V

Electrical resistance

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

Dynamic viscosity

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

Kinematic viscosity

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

Electric charge, Q
Name of unit	Symbol	Definition	Relation to SI units
coulomb (SI unit)	C		≡ A·s
atomic unit of charge	au	≡ e	≈ 1.602 176 462×10⁻¹⁹ C
statcoulomb; franklin; electrostatic unit (cgs unit)	statC; Fr; esu	≡ (0.1 A·m) /c	≈ 3.335 641×10⁻¹⁰ C
abcoulomb; electromagnetic unit (cgs unit)	abC; emu		≡ 10 C
faraday	F	≡ 1 mol × N_A·e	≈ 96,485.3383 C

Information entropy, H
Name of unit	Symbol	Definition	Relation to SI units
SI unit	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 (kibibyte)	KB; KiB	≡ 1024 B	= 7.839695(13) × 10⁻²³ J/K

Temperature, T
Name of unit	Symbol	Relation to SI units	Relation to °C
kelvin	K	SI base unit	T[K] = T[°C] + 273.15
degree Celsius	°C	T[°C] = T[K] − 273.15
degree Rankine	°R; °Ra	T[°Ra] = 1.8 × T[K]
degree Fahrenheit	°F	T[°F] = T[K] × 1.8 − 459.67	T[°F] = 1.8 × T[°C] + 32