From Wikipedia, the free encyclopedia
Conversion of units refers to conversion factors between different units of measurement for the same quantity.
[edit] Techniques
[edit] 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.
[edit] 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.
[edit] Tables of conversion factors
[edit] Legend
Legend
| ≡ |
definition |
| = |
exactly equal to |
| ≈ |
approximately equal to |
| (digits) |
indicates the digits repeat infinitely |
[edit] Luminance
[edit] 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 |
≡ 1×10−10 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 59×10−11 ± 3.6×10−20 m[1] |
| barley corn |
|
≡ ⅓ in |
= 0.0846 m |
| 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 nmi |
= 185.2 m |
| cable length (U.S.) |
|
≡ 720 ft |
= 219.456 m |
| calibre |
cal |
≡ 1 in |
= 0.0254 m |
| chain (Gunter's; Surveyor's) |
ch |
≡ 66.0 ft (4 rods) |
= 20.1168 m |
| chain (Ramsden's; Engineer's) |
ch |
≡ 100 ft |
= 30.48 m |
| cubit |
|
≡ 18 in |
= 0.4572 m |
| ell |
ell |
≡ 45 in |
= 1.143 m |
| fathom |
fm |
≡ 6 ft |
= 1.8288 m |
| fathom |
fm |
≈ 1/1000 nmi[citation needed] |
= 1.852 m |
| fermi |
fm |
≡ 1×10−15 m |
= 1×10−15 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 ×10−4 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 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) |
≈ 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 |
= 1.27×10−4 m |
| micron |
µ |
|
≡ 1×10−6 m |
| mil; thou |
mil |
≡ 1×10−3 in |
= 2.54×10−5 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 ×1016 ± 6×106 m [4] |
| point (ATA) |
pt |
≡ 0.013837 in[citation needed] |
= 0.000 351 459 8 m |
| point (Didot; European) |
pt |
|
≡ 0.000 376 065 m[citation needed] |
| point (metric) |
pt |
≡ 3/8 mm |
= 0.000 375 m[citation needed] |
| point (PostScript) |
pt |
≡ 1/72 in |
≈ 0.000 352 778 m |
| quarter |
|
≡ ¼ yd |
= 0.2286 m |
| rod; pole; perch |
rd |
≡ 16 ½ ft |
= 5.0292 m |
| rope |
rope |
≡ 20 ft |
= 6.096 m |
| span |
|
≡ 6 in |
= 0.1524 m |
| span (cloth) |
|
≡ 9 in |
= 0.2286 m |
| spat[3] |
|
≡ 1012 m |
= 1×1012 m |
| stick |
|
≡ 2 in |
= 0.05 08 m |
| stigma; pm |
|
≡ 1×10−12 m |
≡ 1×10−12 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 ≡ 36 in |
= 0.9144 m[2] |
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 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 BTUIT/h) |
≈ 12.958 174 m² |
| circular inch |
circ in |
≡ π/4 sq in |
≈ 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 |
= 10 000 m² |
| hide |
|
≡ 100 ac |
= 4.046 856 422 4×105 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 |
= 9.290 304×10−2 m² |
| square inch |
sq in |
≡ 1 in × 1 in |
= 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 mil × 1 mil |
= 6.4516×10−10 m² |
| square mile; section |
sq mi |
≡ 1 mi × 1 mi |
= 2.589 988 110 336×106 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 49×10-2 m² |
| square U.S. Survey mile |
sq mi |
≡ 1 sq mi (US) |
≈ 2.589 998×106 m² |
| square yard |
sq yd |
≡ 1 yd × 1 yd |
= 0.836 127 36 m² |
| stremma |
|
≡ 1000 m² |
= 1000 m² |
| township |
|
≡ 36 sq mi (US) |
≈ 9.323 994×107 m² |
| yardland |
|
≡ 30 ac |
= 1.214 056 926 72×105 m² |
[edit] 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 ×10−9 m³ |
| drop (metric) |
|
≡ 1/20 mL |
= 5 ×10−9 m³ |
| minim (Imperial) |
min |
≡ 1/480 fl oz (Imp) = 1/60 fl dr (Imp) |
≈ 5.9 193 880 208 333 ×10−9 m³ |
| minim (U.S.) |
min |
≡ 1/480 US fl oz = 1/60 US fl dr |
= 6.1 611 519 921 875 ×10−9 m³ |
| drop (U.S.) (alt) |
gtt |
≡ 1/456 US fl oz |
≈ 6.4 854 231 ×10−9 m³ |
| drop (Imperial) (alt) |
gtt |
≡ 1/1824 gi (Imp) |
≈ 7.7 886 684 ×10−9 m³ |
| drop (U.S.) |
gtt |
≡ 1/360 US fl oz |
= 8.2 148 693 229 16 ×10−9 m³ |
| drop (medical) |
|
≡ 1/12 mL |
= 83 ×10−9 m³ |
| drop (Imperial) |
gtt |
≡ 1/288 fl oz (Imp) |
= 9.8 656 467 0138 ×10−9 m³ |
| dash (U.S.) |
|
≡ 1/96 US fl oz = ½ US pinch |
= 0.0308 057 599 609 375 ×10−6 m³ |
| dash (Imperial) |
|
≡ 1/384 gi (Imp) = ½ pinch (Imp) |
= 0.0369 961 751 302 083 ×10−6 m³ |
| pinch (U.S.) |
|
≡ 1/48 US fl oz = ⅛ US tsp |
= 0.0616 115 199 218 75 ×10−6 m³ |
| pinch (Imperial) |
|
≡ 1/192 gi (Imp) = ⅛ tsp (Imp) |
= 0.0739 923 502 604 16 ×10−6 m³ |
| fluid scruple (Imperial) |
fl s |
≡ 1/24 fl oz (Imp) |
= 0.1183 877 604 16 ×10−6 m³ |
| fluid drachm (Imperial) |
fl dr |
≡ ⅛ fl oz (Imp) |
= 0.3551 632 812 5 ×10−6 m³ |
| fluid dram (U.S.); U.S. fluidram |
fl dr |
≡ ⅛ US fl oz |
= 0.3696 691 195 312 5 ×10−6 m³ |
| teaspoon (Canadian) |
tsp |
≡ 1/6 fl oz (Imp) |
≈ 0.4735 510 416 667 ×10−6 m³ |
| teaspoon (U.S.) |
tsp |
≡ 1/6 US fl oz |
= 0.4928 921 595 ×10−6 m³ |
| teaspoon (metric) |
|
|
≡ 0.5 ×10−6 m³ |
| teaspoon (Imperial) |
tsp |
≡ 1/24 gi (Imp) |
= 0.5919 388 020 83 ×10−6 m³ |
| dessertspoon (Imperial) |
|
≡ 1/12 gi (Imp) |
= 1.1838 776 0416 ×10−6 m³ |
| tablespoon (Canadian) |
tbsp |
≡ ½ fl oz (Imp) |
= 1.4206 531 25 ×10−6 m³ |
| tablespoon (U.S.) |
tbsp |
≡ ½ US fl oz |
= 1.4786 764 782 5 ×10−6 m³ |
| tablespoon (metric) |
|
|
≡ 1.5 ×10−6 m³ |
| cubic inch |
cu in |
≡ 1 in × 1 in × 1 in |
= 1.6387 064 ×10−5 m³ |
| tablespoon (Imperial) |
tbsp |
≡ 5/8 fl oz (Imp) |
= 1.7758 164 0625 ×10−6 m³ |
| pony |
|
≡ 3/4 US fl oz |
= 2.218 014 717 187 5 ×10−6 m³ |
| fluid ounce (Imperial) |
fl oz (Imp) |
≡ 1/160 gal (Imp) |
= 2.8413 062 5 ×10−6 m³ |
| fluid ounce (U.S.) |
US fl oz |
≡ 1/128 gal (US) |
= 2.9573 529 5625 ×10−6 m³ |
| shot |
|
≡ 1 US fl oz |
= 2.9573 529 5625 ×10−6 m³ |
| jigger |
|
≡ 1½ US fl oz |
= 4.4360 294 343 75 ×10−6 m³ |
| gill (U.S.) |
gi (US) |
≡ 4 US fl oz |
= 11.8294 118 25 ×10−6 m³ |
| gill (Imperial); Noggin |
gi (Imp); nog |
≡ 5 fl oz (Imp) |
= 14.2065 312 5 ×10−6 m³ |
| cup (Canadian) |
c (CA) |
≡ 8 fl oz (Imp) |
= 22.73045 ×10−6 m³ |
| cup (U.S.) |
c (US) |
≡ 8 US fl oz ≡ 1/16 gal (US) |
= 23.6588 2365 ×10−6 m³ |
| cup (metric) |
c |
|
≡ 25.0 ×10−6 m³ |
| breakfast cup |
|
≡ 10 fl oz (Imp) |
= 28.4130 625 ×10−6 m³ |
| pint (U.S. fluid) |
pt (US fl) |
≡ ⅛ gal (US) |
= 47.3176 473 ×10−6 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
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| radian (SI unit) |
rad |
≡ 180°/π |
1 rad |
| centesimal second of arc |
" |
≡ 1 grad/10000 |
≈ 1.57 079 6×10−6 rad |
| arcsecond |
" |
≡ 1°/3600 |
≈ 4.84 813 7×10−6 rad |
| centesimal minute of arc |
' |
≡ 1 grad/100 |
≈ 15.708 0×10−6 rad |
| minute of arc |
' |
≡ 1°/60 |
≈ 29.088 8×10−6 rad |
| angular mil |
µ |
≡ 2π/6400 rad |
≈ 9.8174 8×10−4 rad |
| grad; gradian; gon |
grad |
≡ 2π/400 rad = 0.9° |
≈ 1.570 796 3×10−3 rad |
| degree (of arc) |
° |
≡ π/180 rad |
≈ 1.745 329 3×10−3 rad |
| sign |
|
≡ 30° |
≈ 0.523 599 rad |
| octant |
|
≡ 45° |
≈ 0.785 398 rad |
| sextant |
|
≡ 60° |
≈ 1.047 198 rad |
| quadrant |
|
≡ 90° |
≈ 1.570 796 rad |
[edit] Solid angle
Note: see Weight for detail of mass/weight distinction and conversion
Mass
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| kilogram, grave(SI base unit) |
kg; G |
|
= 1kg |
| electron rest mass |
me |
|
≈ 9.109 381 88×10−31 ± 72×10−39 kg |
| atomic unit of mass |
amu[citation needed] |
≡ me |
≈ 9.109 381 88×10−31 ± 72×10−39 kg |
| unified atomic mass unit |
u |
|
≈ 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 ×10-6 kg |
| point |
|
≡ 1/100 kt (metric) |
= 2 ×10-6 kg |
| mite |
|
≡ 1/20 gr |
= 3.239 945 5 ×10-6 kg |
| mite (metric) |
|
≡ 1/20 g |
= 50 ×10-6 kg |
| grain |
gr |
|
≡ 64.798 91 ×10-6 kg |
| crith |
|
|
≈ 89.9349 ×10-6 kg |
| carat (metric) |
ct |
|
≡ 200 ×10-6 kg |
| carat |
kt |
≡ 3 1/6 gr |
≈ 205.196 548 333 ×10-6 kg |
| sheet |
|
≡ 1/700 lb av |
= 647.9891 ×10-6 kg |
| scruple (apothecary) |
s ap |
≡ 20 gr |
= 1.295 978 2 ×10-3 kg |
| pennyweight |
dwt; pwt |
≡ 1/20 oz t |
= 1.555 173 84 ×10-3 kg |
| dram (avoirdupois) |
dr av |
≡ 27 11/32 gr |
= 1.771 845 195 312 5 ×10-3 kg |
| dram (apothecary; troy) |
dr t |
≡ 60 gr |
= 3.887 934 6 ×10-3 kg |
| hyl (CGS unit) |
|
≡ 1 gee × 1 g × 1 s²/m |
= 9.806 65 ×10-3 kg |
| ounce (avoirdupois) |
oz av |
≡ 1/16 lb |
= 28.349 523 125 ×10-3 kg |
| assay ton (short) |
AT |
≡ 1 mg × 1 sh tn ÷ 1 oz t |
≈ 29.166 667 ×10-3 kg |
| ounce (apothecary; troy) |
oz t |
≡ 1/12 lb t |
= 31.103 476 8 ×10-3 kg |
| assay ton (long) |
AT |
≡ 1 mg × 1 long tn ÷ 1 oz t |
≈ 32.666 667 ×10-3 kg |
| mark |
|
≡ 8 oz t |
= 248.827 814 4 ×10-3 kg |
| pound (troy) |
lb t |
≡ 5760 grains |
= 0.373 241 721 6 kg |
| pound (avoirdupois) |
lb av |
≡ 7000 grains |
= 0.453 592 37 kg |
| pound (metric) |
|
|
≡ 0.5 kg |
| clove |
|
≡ 8 lb av |
= 3.628 738 96 kg |
| stone |
st |
≡ 14 lb av |
= 6.350 293 18 kg |
| hyl (MKS unit) |
|
≡ 1 gee × 1 kg × 1 s²/m |
= 9.806 65 kg |
| quarter (Imperial) |
|
≡ 1/4 long cwt = 2 st = 28 lb av |
= 12.700 586 36 kg |
| slug; geepound |
slug |
≡ 1 gee × 1 lb av × 1 s²/ft |
≈ 14.593 903 kg |
| bag (Portland cement) |
|
≡ 94 lb av |
= 42.637 682 78 kg |
| short hundredweight; cental |
sh cwt |
≡ 100 lb av |
= 45.359 237 kg |
| long hundredweight |
long cwt or cwt |
≡ 112 lb av |
= 50.802 345 44 kg |
| bag (coffee) |
|
≡ 60 kg |
= 60 kg |
| quintal (metric) |
q |
|
≡ 100 kg |
| wey |
|
≡ 252 lb = 18 st (variants exist) |
= 114.305 277 24 kg |
| long quarter (informal) |
|
≡ ¼ long tn |
= 254.011 727 2 kg |
| quarter (informal) |
|
≡ ¼ short tn |
= 226.796 185 kg |
| kip |
kip |
≡ 1000 lb av |
= 453.592 37 kg |
| short ton |
sh tn |
≡ 2000 lb |
= 907.184 74 kg |
| tonne (mts unit) |
t |
|
≡ 1000 kg |
| long ton |
long tn or ton |
≡ 2240 lb |
= 1016.046 908 8 kg |
| barge |
|
≡ 22 ½ sh tn |
= 20,411.656 65 kg |
| Zentner |
Ztr. |
Definitions vary; see [6] and [7]. See also discussion at Talk:Conversion of units#Zentner |
|
In physics, the pound of mass is sometimes written lbm to distinguish it from the pound-force (lbf). It should not be read as the mongrel unit "pound metre".
Time, t
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| second (SI base unit) |
s |
|
= 1 s |
| Planck time |
|
≡ (Gℏ/c5)½ |
≈ 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 |
= 100×10-13 s |
| shake |
|
≡ 10−8 s |
= 10×10-8 s |
| sigma |
|
≡ 10−6 s |
= 10×10-6 s |
| jiffy |
|
≡ 1/60 s |
≈ .016667 s |
| jiffy (alternate) |
|
≡ 1/100 s |
= 10 ms |
| helek |
|
≡ 1/1080 h |
≈ 3.333333 s |
| minute |
min |
|
≡ 60 s |
| milliday |
md |
≡ 86 400 s / 1000 |
≡ 86.4 s |
| moment |
|
≡ 90 s |
≡ 90 s |
| ke(traditional) |
|
≡ 1/100 d |
≡ 864 s |
| quarter (of an hour) |
ke |
≡ 1/96 d |
≡ 900 s |
| hour |
h |
≡ 60 min |
= 3600 s |
| day |
d |
≡ 24 h |
= 86 400 s |
| week |
wk |
≡ 7 d |
= 604 800 s |
| fortnight |
|
≡ 2 wk |
= 1 209 600 s |
| month (hollow) |
mo |
≡ 29 d |
= 2 505 600 s |
| month |
mo |
≡ 30 d |
= 2 592 000 s |
| month (full) |
mo |
≡ 31 d |
= 2 678 400 s |
| year (Calendar) |
a, y, or yr |
≡ 365 d |
= 31 536 000 s |
| year (Gregorian) |
a, y, or yr |
≡ 365.2425 d |
= 31 556 952 s |
| year (Julian) |
a, y, or yr |
≡ 365.25 d |
= 31 557 600 s |
| sidereal year |
a, y, or yr |
≡ 365.256363 d |
= 31 558 149.76 s |
| Olympiad |
|
≡ 4 a of 365 d |
= 1.2614×108 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 |
[edit] Speed or velocity
A velocity consists of a speed combined with a direction; the speed part of the velocity takes units of speed.
[edit] Acceleration
Force
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| newton (SI unit) |
N |
≡ kg·m/s² |
= 1 N |
| atomic unit of force |
au |
≡ me·α²·c²/a0 |
≈ 8.238 722 241×10−8 N |
| dyne (cgs unit) |
dyn |
≡ g·cm/s² |
= 10−5 N |
| milligrave-force, gravet-force |
mGf; gf |
≡ g × 1 g |
= 9.806 65 mN |
| poundal |
pdl |
≡ 1 lb·ft/s² |
= 0.138 254 954 376 N |
| ounce-force |
ozf |
≡ g × 1 oz |
= 0.278 013 850 953 781 2 N |
| pound-force |
lbf |
≡ g × 1 lb |
= 4.448 221 615 260 5 N |
| kilogram-force; kilopond; grave-force |
kgf; kp; Gf |
≡ g × 1 kg |
= 9.806 65 N |
| sthene (mts unit) |
sn |
≡ 1 t·m/s² |
= 1 ×10−3 N |
| kip; kip-force |
kip; kipf; klbf |
≡ g × 1000 lb |
= 4.448 221 615 260 5 ×103 N |
| ton-force |
tnf |
≡ g × 1 sh tn |
= 8.896 443 230 521 ×103 N |
See also: Conversion between weight (force) and mass
[edit] Pressure or mechanical stress
Pressure
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| atmosphere (standard) |
atm |
|
≡ 101 325 Pa [8] |
| atmosphere (technical) |
at |
≡ 1 kgf/cm² |
= 98.0665 ×10−3 Pa [8] |
| bar |
bar |
|
≡ 105 Pa |
| barye (cgs unit) |
|
≡ 1 dyn/cm² |
= 0.1 Pa |
| centimetre of mercury |
cmHg |
≡ 13 595.1 kg/m³ × 1 cm × g |
≈ 1.333 22 ×10−3 Pa [8] |
| centimetre of water (4 °C) |
cmH2O |
≈ 999.972 kg/m³ × 1 cm × g |
≈ 98.0638 Pa [8] |
| foot of mercury (conventional) |
ftHg |
≡ 13 595.1 kg/m³ × 1 ft × g |
≈ 40.636 66 ×10−3 Pa [8] |
| foot of water (39.2 °F) |
ftH2O |
≈ 999.972 kg/m³ × 1 ft × g |
≈ 2.988 98 ×10−3 Pa [8] |
| inch of mercury (conventional) |
inHg |
≡ 13 595.1 kg/m³ × 1 in × g |
≈ 3.386 389 ×10−3 Pa [8] |
| inch of water (39.2 °F) |
inH2O |
≈ 999.972 kg/m³ × 1 in × g |
≈ 249.082 Pa [8] |
| kilogram-force per square millimetre |
kgf/mm² |
≡ 1 kgf/mm² |
= 9.806 65 ×10−6 Pa [8] |
| kip per square inch |
ksi |
≡ 1 kipf/sq in |
≈ 6.894757 ×10−6 Pa [8] |
| millimetre of mercury |
mmHg |
≡ 13 595.1 kg/m³ × 1 mm × g ≈ 1 torr |
≈ 133.322 4 Pa [8] |
| millimetre of water (3.98 °C) |
mmH2O |
≈ 999.972 kg/m³ × 1 mm × g = 0.999972 kgf/m² |
= 9.806 38 Pa |
| pascal (SI unit) |
Pa |
≡ N/m² = kg/(m·s²) |
= 1 Pa [9] |
| pièze (mts unit) |
pz |
≡ 1000 kg/m·s² |
= 1 ×10−3 Pa |
| pound per square foot |
psf |
≡ 1 lbf/ft² |
≈ 47.880 25 Pa [8] |
| poundal per square foot |
pdl/sq ft |
≡ 1 pdl/sq ft |
≈ 1.488 164 Pa [8] |
| pound per square inch |
psi |
≡ 1 lbf/in² |
≈ 6.894 757 ×10+3 Pa [8] |
| short ton per square foot |
|
≡ 1 sh tn × g / 1 sq ft |
≈ 95.760 518 ×10−3 Pa |
| torr |
torr |
≡ 101 325/760 Pa |
≈ 133.322 4 Pa [8] |
[edit] Torque
Torque
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| Newton metre (SI unit) |
N·m |
≡ N × m = kg·m²/s² |
= 1 N·m |
| foot-poundal |
ft pdl |
≡ 1 lb·ft²/s² |
= 4.214 011 009 380 48×10−2 N·m |
| inch-pound force |
in lbf |
≡ g × 1 lb × 1 in |
= 0.112 984 829 027 616 7 N·m |
| foot-pound force |
ft lbf |
≡ g × 1 lb × 1 ft |
= 1.355 817 948 331 400 4 N·m |
[edit] Energy
Energy
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| joule (SI unit) |
J |
≡ m·N = W·s = V·A·s = kg·m²/s² |
= 1 J |
| electronvolt |
eV |
≡ e × 1 V |
≈ 1.602 176×10−19 J |
| rydberg |
Ry |
≡ R∞·ℎ·c |
≈ 2.179 872×10−18 J |
| hartree |
Eh |
≡ me·α²·c² (= 2 Ry) |
≈ 4.359 744×10−18 J |
| atomic unit of energy |
au |
≡ Eh |
≈ 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) |
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 |
| kilocalorie; large calorie |
kcal; Cal |
≡ 1000 calIT |
= 4.1868 ×103 J |
| litre-atmosphere |
l atm; sl |
≡ 1 atm × 1 L |
= 101.325 J |
| gallon-atmosphere (US) |
US gal atm |
≡ 1 atm × 1 gal (US) |
= 383.556 849 013 8 J |
| gallon-atmosphere (imperial) |
imp gal atm |
≡ 1 atm × 1 gal (imp) |
= 460.632 569 25 J |
| British thermal unit (thermochemical) |
BTUth |
|
≈ 1.054 350 ×103 J |
| British thermal unit (ISO) |
BTUISO |
|
≡ 1.0545 ×103 J |
| British thermal unit (63 °F) |
BTU63 °F |
|
≈ 1.0546 ×103 J |
| British thermal unit (60 °F) |
BTU60 °F |
|
≈ 1.054 68 ×103 J |
| British thermal unit (59 °F) |
BTU59 °F |
|
≡ 1.054 804 ×103 J |
| British thermal unit (International Table) |
BTUIT |
|
= 1.055 055 852 62 ×103 J |
| British thermal unit (mean) |
BTUmean |
|
≈ 1.055 87 ×103 J |
| British thermal unit (39 °F) |
BTU39 °F |
|
≈ 1.059 67 ×103 J |
| Celsius heat unit (International Table) |
CHUIT |
≡ 1 BTUIT × 1 K/°R |
= 1.899 100 534 716 ×103 J |
| cubic foot of atmosphere; standard cubic foot |
cu ft atm; scf |
≡ 1 atm × 1 ft³ |
= 2.869 204 480 934 4 ×103 J |
| cubic yard of atmosphere; standard cubic yard |
cu yd atm; scy |
≡ 1 atm × 1 yd³ |
= 77.468 520 985 228 8 ×103 J |
| cubic foot of natural gas |
|
≡ 1000 BTUIT |
= 1.055 055 852 62 ×106 J |
| horsepower-hour |
hp·h |
≡ 1 hp × 1 h |
= 2.684519537696172792 ×106 J |
| kilowatt-hour; Board of Trade Unit |
kW·h; B.O.T.U. |
≡ 1 kW × 1 h |
= 3.6 ×106 J |
| thermie |
th |
≡ 1 McalIT |
= 4.1868 ×106 J |
| therm (U.S.) |
|
≡ 100 000 BTU59 °F |
= 105.4804 ×106 J |
| therm (E.C.) |
|
≡ 100 000 BTUIT |
= 105.505 585 262 ×106 J |
| ton of TNT |
tTNT |
≡ 1 Gcalth |
= 4.184 ×109 J |
| barrel of oil equivalent |
bboe |
≈ 5.8 MBTU59 °F |
≈ 6.12 ×109 J |
| ton of coal equivalent |
TCE |
≡ 7 Gcalth |
= 29.3076 ×109 J |
| ton of oil equivalent |
TOE |
≡ 10 Gcalth |
= 41.868 ×109 J |
| quad |
|
≡ 1015 BTUIT |
= 1.055 055 852 62×1018 J |
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] |
≈ 1.333×10−4 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 |
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 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 BTUIT × 1 sh tn/lb ÷ 10 min/s |
≈ 3.516 853×103 W |
| ton of refrigeration (Imperial) |
|
≡ 1 BTUIT × 1 lng tn/lb ÷ 10 min/s |
≈ 3.938 875×103 W |
| boiler horsepower |
bhp |
≈ 34.5 lb/h × 970.3 BTUIT/lb |
≈ 9.810 657×103 W |
[edit] Angular momentum
Action, Angular momentum
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| SI unit |
J·s |
≡ kg·m²/s |
= 1 J·s |
| atomic unit of action |
au |
≡ ℏ = ℎ/2π |
≈ 1.054 571 596×10−34 J·s |
| cgs unit |
erg·s |
|
= 10−7 J·s |
[edit] Electric current
[edit] Electric charge
[edit] Electromotive force
Voltage, Electromotive force
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| volt (SI unit) |
V |
≡ kg·m²/(A·s³) |
= 1 V |
| abvolt (cgs unit) |
abV |
|
≡ 1×10−8 V |
| statvolt (cgs unit) |
statV |
≡ c· (1 μJ/A·m) |
= 299.792 458 V |
[edit] Electrical resistance
[edit] 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 |
[edit] Dynamic viscosity
[edit] Kinematic viscosity
[edit] Information entropy
Information entropy
| Name of unit |
Symbol |
Definition |
Relation to SI units |
| SI unit |
J/K |
≡ J/K |
= 1 J/K |
| nat; nip; nepit |
nat |
≡ 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.
[edit] 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 |
[edit] Radioactivity
[edit] Radioactivity - absorbed dose
[edit] Radioactivity - equivalent dose
[edit] Software tools
Home and office computers come with converters in bundled spreadsheet applications or can access free converters via the Internet. Units and measurements can be easily converted using these tools, but only if the units are explicitly defined and the conversion is compatible (e.g., cmHg to kPa).
[edit] Free conversion software
[edit] General commercial sources of converters
[edit] References
- ^ "NIST Reference on Constants, Units, and Uncertainty."(2006). National Institute of Standards and Technology. Accessed 22 February 2008.
- ^ a b 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
- ^ a b c d e f g h i j k l m n o 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/
- Klein, Herbert. 1988. The science of measurement: A historical survey. New York: Dover Publications.
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