Conversion of units refers to conversion factors between different units of measurement for the same quantity.
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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
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
|
= 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
|
= 0.000 351 459 8 m
|
| point (Didot; European) |
pt
|
|
≡ 0.000 376 065 m
|
| point (metric) |
pt
|
≡ 3/8 mm
|
= 0.000 375 m
|
| 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 BTUIT/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
Solid angle
Mass
Note: see Weight for detail of mass/weight distinction and conversion
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
Speed or velocity
A velocity consists of a speed combined with a direction; the speed part of the velocity takes units of speed.
Acceleration
Force
See also: Conversion between weight (force) and mass
Pressure or mechanical stress
Torque
Energy
Subscript textSuperscript 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 |
BTUIT/h
|
≡ 1 BTUIT/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 |
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 |
atm·cfm
|
≡ 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 |
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 |
BTUIT/s
|
≡ 1 BTUIT/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 BTUIT × 1 sh tn/lb ÷ 10 min/s
|
≈ 3.516 853Template:E W
|
| ton of refrigeration (Imperial) |
|
≡ 1 BTUIT × 1 lng tn/lb ÷ 10 min/s
|
≈ 3.938 875Template:E W
|
| boiler horsepower |
bhp
|
≈ 34.5 lb/h × 970.3 BTUIT/lb
|
≈ 9.810 657Template:E W
|
Angular momentum
Electric current
Electric charge
Electromotive force
Electrical resistance
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
Kinematic viscosity
Information entropy
| Name of unit
|
Symbol
|
Definition
|
Relation to SI units
|
| SI unit |
J/K
|
≡ 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 (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
|
Definition
|
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 – absorbed dose
Radioactivity – equivalent dose
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
General commercial sources of 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.
See also
Template:Systems of measurement
External links
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