Conversion of units

Name of unit	Symbol	Relation to SI units
Length, l
metre (SI base unit)	m	≡ m
Fermi	fm	≡ 10^-15 m = 1 fm
x unit; siegbahn	xu	≈ 1.0021×10^-13 m
stigma		≡ 1×10^-12 m = 1 pm
Bohr radius	a₀; b	≡ α/(4πR_∞) ≈ 5.291 772 083×10^-11 ± 19×10^-20 m
atomic unit of length	au	≡ a₀ ≈ 5.291 772 083×10^-11 ± 19×10^-20 m
ångström	Å	≡ 10^-10m = 0.1 nm
micron	μ	≡ 10^-6m = 1 μm
twip	twp	≡ 1/1440 in ≈ 1.763 889×10^-5 m
mil; thou	mil	≡ 10^-3 in = 2.54×10^-5 m
mickey		≡ 1/200 in = 1.27×10^-4 m
calibre	cal	≡ 1/100 in = 0.254 mm
point (ATA)	pt	≡ 0.013837 in = 0.351 459 8 mm
point (PostScript)	pt	≡ 1/72 in ≈ 0.352 778 mm
point (metric)	pt	≡ 3/8 mm = 0.375 mm
point (Didot; European)	pt	≡ 0.376 065 mm
line	ln	≡ 1/12 in ≈ 2.116 667 mm
line (Paris) ["ligne"]	l	≡ 1/12 p = 1/443.296 m ≈ 2.255 829 mm
line (Quebec) ["ligne"]	l (Qc)	≡ 1/12 p (Qc) = 2.255 837 5 mm
barley corn		≡ 1/3 in ≈ 8.466 667 mm
finger		≡ 7/8 in = 22.225 mm
inch	in	≡ 1/36 yd = 25.4 mm
U.S. survey inch	in	≡ 1/12 U.S. survey foot = 100/3937 m ≈ 25.400051 mm
inch (Paris) ["pouce"]	p	≡ 1/12 P = 1/(36 + 11.296/12) m ≈ 27.069 949 mm
inch (Quebec) ["pouce"]	p (Qc)	≡ 1/12 P (Qc) = 27.070 05 mm
stick		≡ 2 in = 50.8 mm
nail (cloth)		≡ 2 1/4 in = 57.15 mm
palm		≡ 3 in = 76.2 mm
hand		≡ 4 in = 0.1016 m
finger (cloth)		≡ 4 1/2 in = 0.1143 m
span		≡ 6 in = 0.1524 m
link (Gunter's)	lnk	≡ 66/100 ft = 0.201 168 m
span (cloth)		≡ 9 in = 0.2286 m
quarter		≡ 1/4 yd = 0.2286 m
link (Ramden's; Engineer's)	lnk	≡ 1 ft = 0.3048 m
foot (Clarke's; Cape)	ft (Cla)	≈ 0.304 797 265 4 m
foot (Sear's)	ft (Sear)	≈ 0.304 799 47 m
foot (Indian)	ft Ind	≈ 0.304 799 514 m
foot (Benoît)	ft (Ben)	≈ 0.304 799 735 m
foot	ft	≡ 12 in = 0.3048 m
foot (American; U.S. Survey)	ft (US)	≡ 1200/3937 m ≈ 0.304 800 610 m
foot (Paris) ["pied"]	P	≡ 1/(3 + 11.296/144) m ≈ 0.324 839 385 m
foot (Quebec) ["pied"]	P (Qc)	≡ 1.06575 ft = 0.324 840 6 m
cubit		≡ 18 in = 0.4572 m
pace		≡ 2 1/2 ft = 0.762 m
yard	yd	≡ 3 ft = 0.9144 m
ell	ell	≡ 45 in = 1.143 m
fathom	fm	≡ 6 ft = 1.8288 m (sometimes ≡ 1/1000 NM = 1.852 m)
rod; pole; perch	rd	≡ 16 1/2 ft = 5.0292 m
rope	rope	≡ 20 ft = 6.096 m
chain (Gunter's)	ch	≡ 66 ft = 20.1168 m
chain (Ramden's; Engineer's)	ch	≡ 100 ft = 30.48 m
arpent (Paris)	arp	≡ 180 P = 25 920/443.296 m ≈ 58.471 089 m
arpent (Quebec)	arp (Qc)	≡ 180 P (Qc) = 58.471 308 m
cable length (International)		≡ 1/10 NM = 185.2 m
cable length (Imperial)		≡ 608 ft = 185.3184 m
furlong	fur	≡ 660 ft = 201.168 m
cable length (U.S.)		≡ 720 ft = 219.456 m
mile	mi	≡ 1760 yd = 5280 ft = 1609.344 m
mile (American; Statute; U.S. Survey)	mi	≡ 5280 ft (US) = 5280×1200/3937 m ≈ 1609.347 219 m
nautical mile	NM; nm	≡ 1852 m
nautical mile (Admiralty)	NM (Adm); nm (Adm)	≡ 6080 ft = 1853.184 m
geographical mile	mi	≡ 6082 ft = 1853.7936 m
telegraph mile	mi	≡ 6087 ft = 1855.3176 m
league	lea	≡ 3 mi = 4828.032 m
statute league	lea	≡ 3 mi (US) ≈ 4828.041 656 m
nautical league	NL; nl	≡ 3 NM = 5556 m
light-second		≡ 2.997 924 58×10⁸ m
light-minute		≡ 60 light-seconds = 1.798 754 748×10¹⁰ m
astronomical unit	AU	= 149 597 870.691 ± 0.030 km
spat	S	≡ 10¹² m = 1 Tm
light-hour		≡ 60 light-minutes = 1.079 252 848 8×10¹² m
light-day		≡ 24 light-hours = 2.590 206 837 12×10¹³ m
light-year	l.y.	≡ c₀×86 400×365.25 = 9.460 730 472 580 8×10¹⁵ m
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

Area

Name of unit	Symbol	Relation to SI units
Area, A
square metre (SI unit)	m²	≡ 1 m × 1 m
barn	b	≡ 10^-28 m²
circular mil; circular thou	circ mil	≡ π/4 mil² ≈ 5.067 075×10^-10 m²
square mil; square thou	sq mil	≡ 1 mil² = 6.4516×10^-10 m²
circular inch	circ in	≡ π/4 in² ≈ 5.067 075×10^-4 m²
square inch	sq in	≡ 1 in² = 6.4516×10^-4 m²
board	bd	≡ 1 in × 1 ft = 7.741 92×10^-3 m²
square link	sq lnk	≡ 1 lnk² = 4.046 856 422 4×10^-2 m²
square foot	sq ft	≡ 1 ft² = 9.290 304×10^-2 m²
square yard	sq yd	≡ 1 yd² = 0.836 127 36 m²
cord		≡ 192 bd = 1.486 448 64 m²
boiler horsepower equivalent direct radiation	bhp EDR	≡ 1 sq ft × 1 bhp / 240 BTU_IT/h ≈ 12.958 174 m²
square rod/pole/perch	sq rd	≡ 1 rd² = 25.292 852 64 m²
are	a	≡ 100 m²
square chain	sq ch	≡ 1 ch² = 404.685 642 24 m²
dunam		≡ 1000 m²
rood	ro	≡ 1/4 ac = 1011.714 105 6 m²
acre	ac	≡ 10 sq ch = 4840 sq yd = 4046.856 422 4 m²
hectare	ha	≡ 10 000 m² = 0.01 km²
yardland		≡ 30 ac = 1.214 056 926 72×10⁵ m²
hide		≡ 100 ac = 4.046 856 422 4×10⁵ m²
square kilometre	km²	≡ 1 km² = 10⁶ m²
square mile; section	sq mi	≡ 1 mi² = 2.589 988 110 336×10⁶ m²
square statute mile; square U.S. Survey mile	sq mi	≡ 1 mi (US)² ≈ 2.589 998×10⁶ m²
township		≡ 36 sq mi (US) ≈ 9.323 994×10⁷ m²
barony		≡ 4000 ac = 1.618 742 568 96×10⁷ m²

Volume

Name of unit	Symbol	Relation to SI units
Volume, V
cubic metre (SI unit)	m³	≡ 1
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 = 1/60 fl dr ≈ 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.)	gtt	≡ 1/360 US fl oz ≈ 0.082 148 693 229 167 mL
dram (Imperial fluid); Imperial fluidram	fl dr	≡ 1/8 fl oz = 3.551 632 812 5 mL
dram (U.S. fluid); U.S. fluidram	fl dr	≡ 1/8 US fl oz = 3.696 691 195 312 5 mL
teaspoon (Canadian)	tsp	≡ 1/6 fl oz ≈ 4.735 510 416 667 mL
teaspoon (U.S.)	tsp	≡ 1/6 US fl oz = 4.928 921 595 mL
teaspoon (metric)		≡ 5 mL
tablespoon (Canadian)	tbsp	≡ 1/2 fl oz = 14.206 531 25 mL
tablespoon (U.S.)	tbsp	≡ 1/2 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 = 17.758 164 062 5 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
gill (U.S.)	gi (US)	≡ 4 US fl oz = 118.294 118 25 mL
gill (Imperial); Noggin	gi (Imp); nog	≡ 5 Imp fl oz = 142.065 312 5 mL
cup (Canadian)	c (CA)	≡ 8 fl oz (Imp) = 227.3045 mL
cup (U.S.)	c (US)	≡ 1/16 gal (US) = 236.588 236 5 mL
cup (Metric)	c	≡ 250 mL
pint (U.S. fluid)	pt (US fl)	≡ 1/8 gal (US) = 473.176 473 mL
pint (U.S. dry)	pt (US dry)	≡ 1/4 bu (US lvl) = 550.610 471 357 5 mL
pint (Imperial)	pt (Imp)	≡ 1/8 gal (Imp) = 568.261 25 mL
quart (U.S. fluid)	qt (US)	≡ 1/4 gal (US fl) = 0.946 352 946 L
quart (U.S. dry)	qt (US)	≡ 1/32 bu (US lvl) = 1/4 gal (US dry) = 1.101 220 942 715 L
quart (Imperial)	qt (Imp)	≡ 1/4 gal (Imp) = 1.136 522 5 L
board-foot	fbm	≡ 144 cu in = 2.359 737 216 L
gallon (U.S. fluid)	gal (US)	≡ 231 cu in = 3.785 411 784 L
gallon (U.S. dry)	gal (US)	≡ 1/8 bu (US lvl) = 4.404 883 770 86 L
gallon (Imperial)	gal (Imp)	≡ 4.546 09 L
peck (U.S. dry)	pk	≡ 1/4 US lvl bu = 8.809 767 541 72 L
peck (Imperial)	pk	≡ 2 Imp gal = 9.092 18 L
bucket (Imperial)	bkt	≡ 4 Imp gal = 18.184 36 L
timber foot		≡ 1 cu ft = 28.316 846 592 L
cubic foot	cu ft	≡ 1728 cu in = 28.316 846 592 L
firkin		≡ 9 US gal = 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 1/4 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)	≡ 31 1/2 gal (US) = 119.240 471 196 L
coomb		≡ 4 bu (Imp) = 145.474 88 L
barrel (U.S. oil)	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) = 163.659 24 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 (U.S.)		≡ 126 gal (US) = 0.476 961 884 784 m³
butt (Imperial)		≡ 126 gal (Imp) = 0.572 807 34 m³
perch	per	≡ 16 1/2 ft × 1 1/2 ft × 1 ft = 0.700 841 953 152 m³
cubic yard	cu yd	≡ 27 cu ft = 0.764 554 857 984 m³
displacement ton		≡ 35 cu ft = 0.991 089 630 72 m³
freight ton		≡ 40 cu ft = 1.132 673 863 68 m³
tun		≡ 252 gal (Imp) = 1.145 614 68 m³
chaldron (Imperial)		≡ 32 bu (Imp) = 1.163 799 04 m³
chaldron (U.S.)		≡ 36 bu (US lvl) = 1.268 606 526 007 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		≡ 8 ft × 4 ft × 4 ft = 3.624 556 363 776 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

Name of unit	Symbol	Relation to SI units
Angle
radian	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
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

Mass

Name of unit	Symbol	Relation to SI units
Mass, m
kilogram	kg	(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	≡ 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 (MKSA 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		≡ 94 lb av = 42.637 682 78 kg
short hundredweight; cental	sh cwt	≡ 100 lb av = 45.359 237 kg
long hundredweight (U.S.) or hundredweight (Imperial)	long cwt or cwt	≡ 112 lb av = 50.802 345 44 kg
quintal (metric)		≡ 100 kg
wey		≡ 252 lb = 18 st = 114.305 277 24 kg (variants exist)
short quarter (U.S.)		≡ 1/4 sh tn = 226.796 185 kg
long quarter (U.S.)		≡ 1/4 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 (U.S.) or ton (Imperial)	long tn or ton	≡ 2240 lb = 1016.046 908 8 kg
barge		≡ 22 1/2 sh tn = 20,411.656 65 kg

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

Name of unit	Symbol	Relation to SI units
Time, t
second	s	(SI base unit)
Planck time		≡ √Gh/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 (sometimes ≡ 1/100 s = 10 ms)
minute	min	≡ 60 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 (full)	mo	≡ 30 d = 2 592 000 s
year (Calendar)	a	≡ 365 d = 31 536 000 s
year (Gregorian)	a	≡ 365.2425 d = 31 556 952 s
year (Julian)	a	≡ 365.25 d = 31 557 600 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

Name of unit	Symbol	Relation to SI units
Speed, v
metre per second	m/s	≡ 1 m/s
foot per hour	fph	≡ 1 ft/h ≈ 8.466 667×10^-5 m/s
furlong per fortnight		≈ 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
statute mile per hour	mph	≈ 0.447 041 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

Name of unit	Symbol	Relation to SI units
Acceleration, a
metre per second squared	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 = 0.01 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

Name of unit	Symbol	Relation to SI units
Force, F
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 = 10^-5 N
gravet		≡ 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	kgf; kp	≡ g × 1 kg = 9.806 65 N
sthene (mts unit)	sn	≡ 1 t·m/s² = 1 kN
kip-force	kipf	≡ g × 1 kip = 4.448 221 615 260 5 kN
ton-force	tnf	≡ g × 1 sh tn = 8.896 443 230 521 kN

Pressure

Name of unit	Symbol	Relation to SI units
Pressure, P
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 (4°C)	mmH2O	≡ 1000 kg/m³ × 1 mm × g = 9.806 65 Pa (= 1 kgf/m²)
pound per square foot	psf	≡ 1 lb/sq ft × g ≈ 47.880 259 Pa
centimetre of water (4°C)	cmH2O	≡ 1000 kg/m³ × 1 cm × g = 98.0665 Pa
torr	torr	≡ (101 325/760) Pa ≈ 133.322 Pa
millimetre of mercury	mmHg	≡ 13 595.1 kg/m³ × 1 mm × g = 133.322 387 415 Pa (≈ 1 torr)
inch of water (4°C)	inH2O	≡ 1000 kg/m³ × 1 in × g = 249.088 91 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 (≈ 10 torr)
foot of water (4°C)	ftH2O	≡ 1000 kg/m³ × 1 ft × g = 2.989 066 92 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 ≈ 6.894 757×10³ Pa
foot of mercury	ftHg	&#8801 13 595.1 kg/m³ × 1 ft × g = 40.636 663 684 091 9 kPa
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 or Work

Name of unit	Symbol	Relation to SI units
Energy, E
joule (SI unit)	J	≡ N·m = kg·m²/s²
electronvolt	eV	≡ e × 1 V = 1/6.241 509 629 152 65×10¹⁸ J ≈ 1.602 176×10^-19 J
rydberg	Ry	≡ R_∞·h·c ≈ 2.179 872×10^-18 J
hartree	E_h	≡ m_e·α²·c² ≈ 4.359 744×10^-18 J (= 2Ry)
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 ft·pdl = 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 (4°C)	cal_4°C	≈ 4.2045 J
litre of atmosphere; standard litre	l atm; sl	≡ 1 atm × 1 L = 101.325 J
gallon of atmosphere (U.S.)	gal atm	≡ 1 atm × 1 gal (US) = 383.556 849 013 8 J
gallon of atmosphere (Imperial)	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 cu ft = 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 cu yd = 77.468 520 985 228 8 kJ
cubic foot of natural gas		≡ 1000 BTU_IT = 1.055 055 852 62 MJ
horsepower-hour	hph	≡ 1 hp (electrical imperial) × 1 h = 2.6856 MJ
Board of Trade Unit; kilowatt-hour	B.O.T.U.; kWh	≡ 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

Name of unit	Symbol	Relation to SI units
Power, P
watt (SI unit)	W	≡ J/s = N·m/s = kg·m²/s³
lusec	lusec	≡ 1 L-µmHg/s ≈ 1.333 224×10^-4 W
foot-pound-force per hour	ft lbf/h	≡ 1 ft lbf/h ≈ 3.766 161×10^-4 W
standard cubic centimetre per minute	sccm	≡ 1 atm 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
standard cubic centimetre per second	sccs	≡ 1 atm cm³/s = 0.101 325 W
BTU (International Table) per hour	BTU_IT/h	≡ 1 BTU_IT/h ≈ 0.293 071 W
standard cubic foot per hour	scfh	≡ 1 atm 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
standard litre per minute	slpm	≡ 1 atm 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
standard cubic foot per minute	scfm	≡ 1 atm 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
standard litre per second	slps	≡ 1 atm L/s = 101.325 W
horsepower (metric)	hp	≡ 75 m kgf/s = 735.498 75 W
horsepower (U.S.)	hp (US)	≈ 735.7 W
horsepower (European electrical)	hp	≡ 736 W
horsepower (Imperial mechanical)	hp	≡ 550 ft lbf/s = 745.699 871 582 270 22 W
horsepower (Imperial electrical)	hp	≡ 746 W
horsepower (water)	hp (US)	≈ 746.043 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 62×10⁺³ W
standard cubic foot per second	scfs	≡ 1 atm cu ft/s = 2.869 204 480 934 4×10⁺³ W
ton of refrigeration (IT)		≡ 1 BTU_IT × 1 sh tn/lb ÷ 10 min/s ≈ 3.516 853×10⁺³ W
ton of refrigeration (Imperial)		≡ 1 BTU_IT × 1 lng tn/lb ÷ 10 min/s ≈ 3.938 875×10⁺³ W
boiler horsepower	bhp	≈ 34.5 lb/h × 970.3 BTU_IT/lb ≈ 9.810 657×10⁺³ W

Angular momentum

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

Electric current

Name of unit	Symbol	Relation to SI units
Electric current, I
ampere	A	SI base unit
esu per second; StatAmpere (cgs unit)	esu/s	≡ (0.1 Am/s)/c ≈ 3.335 641×10^-10 A
electromagnetic unit; AbAmpere (cgs unit)	abamp	≡ 10 A

Electric charge

Name of unit	Symbol	Relation to SI units
Electric charge, Q
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 Am)/c ≈ 3.335 641×10^-10 C
AbCoulomb (cgs unit)	AbC	≡ 10 C
Faraday	F	≡ 1 mol × N_A·e ≈ 96,485.3383 C

Electromotive force

Name of unit	Symbol	Relation to SI units
Voltage, Electromotive force, U
volt (SI unit)	V	≡ kg·m²/A·s³
AbVolt (cgs unit)	abV	≡ 1×10^-8 V
StatVolt (cgs unit)	statV	≡ c·(1 μJ/Am) = 299.792 458 V

Electrical resistance

Name of unit	Symbol	Relation to SI units
Electrical resistance, R
ohm (SI unit)	Ω	≡ V/A = kg·m²/A²s³
Dynamic viscosity, η
SI unit	Pa·s	≡ N·s/m² = kg/m·s
poise (cgs unit)	P	≡ 10^-1 Pa·s

Kinematic viscosity

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

Temperature

Name of unit	Symbol	Relation to SI units
Temperature, T
kelvin	K	SI base unit
degree Celsius	°C	T[°C] = T[K] − 273.15
degree Rankine	°R; °Ra	T[°Ra] = (9/5)×T[K]
degree Fahrenheit	°F	T[°F] = T[K] × 1.8 − 459.67 (T[°F] = (9/5)×T[°C] + 32)

External links

A Dictionary of Units of Measurement (http://www.unc.edu/~rowlett/units/index.html)
Conversion of units - Many calculators (http://www.sengpielaudio.com/Calculations03.htm)
Google calculator with unit converter, type in the box e.g. 3 mile to km (http://www.google.com/advanced_search)
• Multi calculator for many units • (http://www.sengpielaudio.com/calculator-multi.htm)
Fundamental Physical Constants — Non-SI units (http://physics.nist.gov/cuu/Document/nonsi_in_1998.pdf)
British Law: Units of Measurement Regulations 1995 (http://www.hmso.gov.uk/si/si1995/Uksi_19951804_en_2.htm)

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Categories: Units of measure

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