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

≡ 1.00010−10 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 08310−11 1910−20 m

barley corn

≡ 1/3 in

≈ 8.466 667 mm

Bohr radius

a0; b

α/(4πR)

≈ 5.291 772 08310−11 1910−20 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

≈ 1/1000 NM

= 1.852 m

fermi

fm

≡ 1.00010−15 m

= 1.00010−15 m

finger

≡ 7/8 in

= 22.225 mm

finger (cloth)

≡ 4 in

= 0.1143 m

foot (Benot)

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 121013 m

light-hour

≡ 60 light-minutes

= 1.079 252 848 81012 m

light-minute

≡ 60 light-seconds

= 1.798 754 7481010 m

light-second

≡ 2.997 924 58108 m

light-year

l.y.

c0 86 400 365.25

= 9.460 730 472 580 81015 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

= 1.2710−4 m

micron

≡ 1.00010−6 m

mil; thou

mil

≡ 1.00010−3 in

= 2.5410−5 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 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 31016 6106 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

≡ yd

= 0.2286 m

rod; pole; perch

rd

≡ 16 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

≡ 1.00010−12 m

≡ 1.00010−12 m

telegraph mile

mi

≡ 6087 ft

= 1855.3176 m

twip

twp

≡ 1/1440 in

≈ 1.763 88910−5 m

x unit; siegbahn

xu

≈ 1.002110−13 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 m

are

a

≡ 100 m

barn

b

≡ 10−28 m

barony

≡ 4000 ac

= 1.618 742 568 96107 m

board

bd

≡ 1 in 1 ft

= 7.741 9210−3 m

boiler horsepower equivalent direct radiation

bhp EDR

≡ (1 ft) (1 bhp) / (240 BTUIT/h)

≈ 12.958 174 m

circular inch

circ in

≡ π/4 in

≈ 5.067 07510−4 m

circular mil; circular thou

circ mil

≡ π/4 mil

≈ 5.067 07510−10 m

cord

≡ 192 bd

= 1.486 448 64 m

dunam

≡ 1000 m

= 1000 m

hectare

ha

≡ 10 000 m

= 0.01 km

hide

≡ 100 ac

= 4.046 856 422 4105 m

rood

ro

≡ ac

= 1011.714 105 6 m

square chain

sq ch

≡ 1 ch

= 404.685 642 24 m

square foot

sq ft

≡ 1 ft

= 9.290 30410−2 m

square inch

sq in

≡ 1 in

= 6.451610−4 m

square kilometre

km

≡ 1 km

= 106 m

square link

sq lnk

≡ 1 lnk

= 4.046 856 422 410−2 m

square metre (SI unit)

m

≡ 1 m 1 m

= 1 m

square mil; square thou

sq mil

≡ 1 mil

= 6.451610−10 m

square mile; section

sq mi

≡ 1 mi

= 2.589 988 110 336106 m

square rod/pole/perch

sq rd

≡ 1 rd

= 25.292 852 64 m

square U.S. Survey mile

sq mi

≡ 1 mi (US)

≈ 2.589 998106 m

square yard

sq yd

≡ 1 yd

= 0.836 127 36 m

stremma

≡ 1000 m

= 1000 m

township

≡ 36 sq mi (US)

≈ 9.323 994107 m

yardland

≡ 30 ac

= 1.214 056 926 72105 m

Volume

Volume, V

Name of unit

Symbol

Definition

Relation to SI units

cubic metre (SI unit)

m

≡ 1 m 1 m 1 m

litre

L

≡ 1 dm

lambda

λ

≡ 1 mm

= 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 = US pinch

= 0.308 057 599 609 375 mL

dash (Imperial)

≡ 1/384 gi (Imp) = 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

≡ fl oz (Imp)

= 14.206 531 25 mL

tablespoon (U.S.)

tbsp

≡ US fl oz

= 14.786 764 782 5 mL

tablespoon (metric)

≡ 15 mL

cubic inch

cu in

≡ 1 in

= 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

≡ 1 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)

≡ gal (US fl)

= 0.946 352 946 L

quart (U.S. dry)

qt (US)

≡ 1/32 bu (US lvl) = gal (US dry)

= 1.101 220 942 715 L

quart (Imperial)

qt (Imp)

≡ gal (Imp)

= 1.136 522 5 L

pottle; quartern

≡ 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

≡ 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 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 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 m

butt, pipe

≡ 126 gal (wine)

= 0.476 961 884 784 m

perch

per

≡ 16 ft 1 ft 1 ft

= 0.700 841 953 152 m

cubic yard

cu yd

≡ 27 cu ft

= 0.764 554 857 984 m

tun

≡ 252 gal (wine)

= 0.953 923 769 568 m

displacement ton

≡ 35 cu ft

= 0.991 089 630 72 m

water ton

≡ 28 bu (Imp)

= 1.018 324 16 m

freight ton

≡ 40 cu ft

= 1.132 673 863 68 m

wey (U.S.)

≡ 40 bu (US lvl)

= 1.409 562 806 675 2 m

load

≡ 50 cu ft

= 1.415 842 329 6 m

register ton

≡ 100 cu ft

= 2.831 684 659 2 m

last

≡ 80 bu (Imp)

= 2.909 497 6 m

cord (firewood)

≡ 8 ft 4 ft 4 ft

= 3.624 556 363 776 m

cubic fathom

cu fm

≡ 1 fm 1 fm 1 fm

= 6.116 438 863 872 m

acre-inch

≡ 1 ac 1 in

= 102.790 153 128 96 m

acre-foot

≡ 1 ac 1 ft

= 1233.481 837 547 52 m

cubic mile

cu mi

≡ 1 mi

= 4.168 181 825 440 579 584 km

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 rad

arcsecond

"

≡ 1/3600

≈ 4.848 137 rad

centesimal minute of arc

'

≡ 1 gr/100

≈ 0.157 080 mrad

minute of arc

'

≡ 1/60

≈ 0.290 888 mrad

angular mil

≡ 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

me

≈ 9.109 381 8810−31 7210−39 kg

atomic unit of mass

au

≡ me

≈ 9.109 381 8810−31 7210−39 kg

unified atomic mass unit

amu

≈ 1.660 538 7310−27 1310−35 kg

dalton

Da

≈ 1.660 902 1010−27 1310−35 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 s/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 s/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 s/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

≡ 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 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/c5)

≈ 1.351 211 81810−43 s

atomic unit of time

au

a0/(αc)

≈ 2.418 884 25410−17 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

= 1.2614108 s

lustre; lustrum

≡ 5 a of 365 d

= 1.5768108 s

octaeteris

≡ 8 a of 365 d

= 2.522 88108 s

decade

≡ 10 a of 365 d

= 3.1536108 s

enneadecaeteris; Metonic cycle

≡ 110 mo (hollow) + 125 mo (full) = 19 a of 365 d

= 5.996 16108 s

Callippic cycle

≡ 441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d

= 2.398 377 6109 s

century (Calendar)

≡ 100 a of 365 d

= 3.1536109 s

century (Julian)

≡ 100 a of 365.25 d

= 3.155 76109 s

Hipparchic cycle

≡ 4 Callippic cycles - 1 d

= 9.593 424109 s

millennium (Calendar)

≡ 1000 a of 365 d

= 3.15361010 s

millennium (Gregorian)

≡ 1000 a of 365.2425 d

= 3.155 695 21010 s

millennium (Julian)

≡ 1000 a of 365.25 d

= 3.155 761010 s

Sothic cycle

≡ 1461 a of 365 d

= 4.607 409 61010 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 66710−5 m/s

furlong per fortnight

≡ fur/wk

≈ 1.663 09510−4 m/s

inch per minute

ipm

≡ 1 in/min

≈ 4.23 33310−4 m/s

foot per minute

fpm

≡ 1 ft/min

= 5.0810−3 m/s

inch per second

ips

≡ 1 in/s

= 2.5410−2 m/s

kilometre per hour

km/h

≡ 1 km/h

≈ 2.777 77810−1 m/s

foot per second

fps

≡ 1 ft/s

= 3.04810−1 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 58108 m/s

Acceleration

Acceleration, a

Name of unit

Symbol

Definition

Relation to SI units

metre per second squared (SI unit)

m/s

≡ 1 m/s

foot per hour per second

fph/s

≡ 1 ft/hs

≈ 8.466 66710−5 m/s

inch per minute per second

ipm/s

≡ 1 in/mins

≈ 4.233 33310−4 m/s

foot per minute per second

fpm/s

≡ 1 ft/mins

= 5.0810−3 m/s

galileo

Gal

≡ 1 cm/s

= 10−2 m/s

inch per second squared

ips

≡ 1 in/s

= 2.5410−2 m/s

foot per second squared

fps

≡ 1 ft/s

= 3.04810−1 m/s

mile per hour per second

mph/s

≡ 1 mi/hs

= 4.470410−1 m/s

knot per second

kn/s

≡ 1 kn/s

≈ 5.144 44410−1 m/s

standard gravity

g

≡ 9.806 65 m/s

mile per minute per second

mpm/s

≡ 1 mi/mins

= 26.8224 m/s

mile per second squared

mps

≡ 1 mi/s

= 1.609 344103 m/s

Force

Force, F

Name of unit

Symbol

Definition

Relation to SI units

newton (SI unit)

N

≡ kgm/s

atomic unit of force

au

≡ meαc/a0

≈ 8.238 722 24110−8 N

dyne (cgs unit)

dyn

≡ gcm/s

ljm = 10−5 N

milligrave-force, gravet

mGf; gf

g 1 g

= 9.806 65 mN

poundal

pdl

≡ 1 lbft/s

= 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 tm/s

= 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/m

= kg/(ms)

barye (cgs unit)

≡ 1 dyn/cm

= 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/m 1 mm g

= 9.806 38 Pa (= 0.999972 kgf/m)

pound per square foot

psf

≡ 1 lb/sq ft g

≈ 47.880 259 Pa

centimetre of water (3.98 C)

cmH2O

≈ 999.972 kg/m 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/m 1 mm g ≈ 1 torr

= 133.322 387 415 Pa

inch of water (3.98 C)

inH2O

≈ 999.972 kg/m 1 in g

= 249.082 Pa

pize (mts unit)

pz

≡ 1000 kg/ms

= 1 kPa

centimetre of mercury

cmHg

≡ 13 595.1 kg/m 1 cm g

= 1.333 223 874 15 kPa

foot of water (3.98 C)

ftH2O

≈ 999.972 kg/m 1 ft g

= 2.988 98 kPa

inch of mercury

inHg

≡ 13 595.1 kg/m 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/m 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/cm

= 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/mm

≡ 1 kgf/mm

= 9.806 65 MPa

Energy, work, or heat

Energy, E

Name of unit

Symbol

Definition

Relation to SI units

joule (SI unit)

J

Nm = Ws = VAs

= kgm/s

electronvolt

eV

e 1 V

≈ 1.602 17610−19 J

rydberg

Ry

Rc

≈ 2.179 87210−18 J

hartree

Eh

≡ meαc (= 2 Ry)

≈ 4.359 74410−18 J

atomic unit of energy

au

≡ Eh ≈ 4.359 74410−18 J

erg (cgs unit)

erg

≡ 1 gcm/s

= 10−7 J

foot-poundal

ft pdl

≡ 1 lbft/s

= 4.214 011 009 380 4810−2 J

cubic centimetre of atmosphere; standard cubic centimetre

cc atm; scc

≡ 1 atm 1 cm

= 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)

cal20 C

≈ 4.1819 J

calorie (thermochemical)

calth

≡ 4.184 J

calorie (15 C)

cal15 C

≡ 4.1855 J

calorie (International Table)

calIT

≡ 4.1868 J

calorie (mean)

calmean

≈ 4.190 02 J

calorie (3.98 C)

cal3.98 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)

BTUth

≡ 1 lb/g 1 calth 1 F/C = 9.4891523804 9 kJ

≈ 1.054 350 kJ

British thermal unit (ISO)

BTUISO

≡ 1.0545 kJ

British thermal unit (63 F)

BTU63 F

≈ 1.0546 kJ

British thermal unit (60 F)

BTU60 F

≈ 1.054 68 kJ

British thermal unit (59 F)

BTU59 F

≡ 1.054 804 kJ

British thermal unit (International Table)

BTUIT

≡ 1 lb/g 1 calIT 1 F/C

= 1.055 055 852 62 kJ

British thermal unit (mean)

BTUmean

≈ 1.055 87 kJ

British thermal unit (39 F)

BTU39 F

≈ 1.059 67 kJ

Celsius heat unit (International Table)

CHUIT

≡ 1 BTUIT 1 C/F

= 1.899 100 534 716 kJ

cubic foot of atmosphere; standard cubic foot

cu ft atm; scf

≡ 1 atm 1 ft

= 2.869 204 480 934 4 kJ

kilocalorie; large calorie

kcal; Cal

≡ 1000 calIT

= 4.1868 kJ

cubic yard of atmosphere; standard cubic yard

cu yd atm; scy

≡ 1 atm 1 yd

= 77.468 520 985 228 8 kJ

cubic foot of natural gas

≡ 1000 BTUIT

= 1.055 055 852 62 MJ

horsepower-hour

hph

≡ 1 hp 1 h

= 2.6845 MJ

kilowatt-hour; Board of Trade Unit

kWh; B.O.T.U.

≡ 1 kW 1 h

= 3.6 MJ

thermie

th

≡ 1 McalIT

= 4.1868 MJ

therm (U.S.)

≡ 100 000 BTU59 F

= 105.4804 MJ

therm (E.C.)

≡ 100 000 BTUIT

= 105.505 585 262 MJ

ton of TNT

tTNT

≡ 1 Gcalth

= 4.184 GJ

barrel of oil equivalent

bboe

≈ 5.8 MBTU59 F

≈ 6.12 GJ

ton of coal equivalent

TCE

≡ 7 Gcalth

= 29.3076 GJ

ton of oil equivalent

TOE

≡ 10 Gcalth

= 41.868 GJ

quad

≡ 1015 BTUIT

= 1.055 055 852 62 EJ

Power

Power, P

Name of unit

Symbol

Definition

Relation to SI units

watt (SI unit)

W

≡ J/s = Nm/s

= kgm2/s3

lusec

lusec

≡ 1 LmHg/s [4]

≈ 1.33310−4 W

foot-pound-force per hour

ft lbf/h

≡ 1 ft lbf/h

≈ 3.766 16110−4 W

atmosphere cubic centimetre per minute

atm ccm

≡ 1 atm 1 cm/min

= 1.688 7510−3 W

foot-pound-force per minute

ft lbf/min

≡ 1 ft lbf/min

= 2.259 696 580 552 33410−2 W

atmospherecubic centimetre per second

atm ccs

≡ 1 atm 1 cm/s

= 0.101 325 W

BTU (International Table) per hour

BTUIT/h

≡ 1 BTUIT/h

≈ 0.293 071 W

atmospherecubic 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

Latm/min

≡ 1 atm 1 L/min

= 1.688 75 W

calorie (International Table) per second

calIT/s

≡ 1 calIT/s

= 4.1868 W

BTU (International Table) per minute

BTUIT/min

≡ 1 BTUIT/min

≈ 17.584 264 W

atmosphere-cubic foot per minute

atmcfm

≡ 1 atm 1 cu ft/min

= 47.820 074 682 24 W

square foot equivalent direct radiation

sq ft EDR

≡ 240 BTUIT/h

≈ 70.337 057 W

litre-atmosphere per second

Latm/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 kpm/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

BTUIT/s

≡ 1 BTUIT/s

= 1.055 055 852 62103 W

atmosphere-cubic foot per second

atm cfs

≡ 1 atm 1 cu ft/s

= 2.869 204 480 934 4103 W

ton of refrigeration (IT)

≡ 1 BTUIT 1 sh tn/lb 10 min/s

≈ 3.516 853103 W

ton of refrigeration (Imperial)

≡ 1 BTUIT 1 lng tn/lb 10 min/s

≈ 3.938 875103 W

boiler horsepower

bhp

≈ 34.5 lb/h 970.3 BTUIT/lb

≈ 9.810 657103 W

Angular momentum

Action, Angular momentum, L, J

Name of unit

Symbol

Definition

Relation to SI units

SI unit

Js

≡ kgm/s

atomic unit of action

au

= /2π

≈ 1.054 571 59610−34 Js

cgs unit

ergs

= 10−7 Js

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 Am/s) /c

≈ 3.335 64110−10 A

electromagnetic unit; abampere (cgs unit)

abamp

≡ 10 A

Electric charge

Electric charge, Q

Name of unit

Symbol

Definition

Relation to SI units

coulomb (SI unit)

C

As

atomic unit of charge

au

e

≈ 1.602 176 46210−19 C

statcoulomb; franklin; electrostatic unit (cgs unit)

statC; Fr; esu

≡ (0.1 Am) /c

≈ 3.335 64110−10 C

abcoulomb; electromagnetic unit (cgs unit)

abC; emu

≡ 10 C

faraday

F

≡ 1 mol NAe

≈ 96,485.3383 C

Electromotive force

Voltage, Electromotive force, U

Name of unit

Symbol

Definition

Relation to SI units

volt (SI unit)

V

≡ kgm/(As)

abvolt (cgs unit)

abV

≡ 110−8 V

statvolt (cgs unit)

statV

c (1 μJ/Am)

= 299.792 458 V

Electrical resistance

Electrical resistance, R

Name of unit

Symbol

Definition

Relation to SI units

ohm (SI unit)

Ω

≡ V/A

= kgm/(As)

Dynamic viscosity

Dynamic viscosity, η

Name of unit

Symbol

Definition

Relation to SI units

pascal second (SI unit)

Pas

≡ Ns/m

= kg/(ms)

poise (cgs unit)

P

≡ 10−1 Pas

Kinematic viscosity

Kinematic viscosity, ν

Name of unit

Symbol

Definition

Relation to SI units

SI unit

m/s

≡ m/s

stokes (cgs unit)

St

≡ 10−4 m/s

Information entropy

Information entropy, H

Name of unit

Symbol

Definition

Relation to SI units

SI unit

J/K

≡ 1 J/K

nat; nip; nepit

nat

kB

= 1.3806505(23) 10−23 J/K

bit; shannon

bit; b; Sh

ln(2) kB

= 9.569940(16) 10−24 J/K

ban; hartley

ban; Hart

ln(10) kB

= 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

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