References

Weights and Measures

Note: At this time, only three countries - Burma, Liberia, and the US - have not adopted the International System of Units (SI, or metric system) as their official system of weights and measures. Although use of the metric system has been sanctioned by law in the US since 1866, it has been slow in displacing the American adaptation of the British Imperial System known as the US Customary System. The US is the only industrialized nation that does not mainly use the metric system in its commercial and standards activities, but there is increasing acceptance in science, medicine, government, and many sectors of industry.

Mathematical Notation
Mathematical PowerName
1018 or 1,000,000,000,000,000,000one quintillion
1015 or 1,000,000,000,000,000one quadrillion
1012 or 1,000,000,000,000one trillion
109 or 1,000,000,000one billion
106 or 1,000,000one million
103 or 1,000one thousand
102 or 100one hundred
101 or 10ten
100 or 1one
10-1 or 0.1one-tenth
10-2 or 0.01one-hundredth
10-3 or 0.001one-thousandth
10-6 or 0.000 001one-millionth
10-9 or 0.000 000 001one-billionth
10-12 or 0.000 000 000 001one-trillionth
10-15 or 0.000 000 000 000 001one-quadrillionth
10-18 or 0.000 000 000 000 000 001one-quintillionth

Metric Interrelationships
PrefixSymbolLength, Weight, or Capacity
yottaY1024
zettaZ1021
exaE1018
petaP1015
teraT1012
gigaG109
megaM106
kilok103
hectoh102
dekada101
basic unit-1 meter, 1 gram, 1 liter
decid10-1
centic10-2
millim10 -3
microu10-6
nanon10-9
picop10-12
femtof10-15
attoa10-18
zeptoz10-21
yoctoy10-24

Conversion Factors
To Convert FromToMultiply By
acresares40.468 564 224
acreshectares0.404 685 642 24
acressquare feet43,560
acressquare kilometers0.004 046 856 422 4
acressquare meters4,046.856 422 4
acressquare miles (statute)0.001 562 50
acressquare yards4,840
aressquare meters100
aressquare yards119.599
barrels, US beergallons31
barrels, US beerliters117.347 77
barrels, US petroleumgallons (British)34.97
barrels, US petroleumgallons (US)42
barrels, US petroleumliters158.987 29
barrels, US proof spiritsgallons40
barrels, US proof spiritsliters151.416 47
bushels (US)bushels (British)0.968 9
bushels (US)cubic feet1.244 456
bushels (US)cubic inches2,150.42
bushels (US)cubic meters0.035 239 07
bushels (US)cubic yards0.046 090 96
bushels (US)dekaliters3.523 907
bushels (US)dry pints64
bushels (US)dry quarts32
bushels (US)liters35.239 070 17
bushels (US)pecks4
cablesfathoms120
cablesmeters219.456
cablesyards240
caratmilligrams200
centimetersfeet0.032 808 40
centimetersinches0.393 700 8
centimetersmeters0.01
centimetersyards0.010 936 13
centimeters, cubiccubic inches0.061 023 744
centimeters, squaresquare feet0.001 076 39
centimeters, squaresquare inches0.155 000 31
centimeters, squaresquare meters0.000 1
centimeters, squaresquare yards0.000 119 599
chains, square surveyor'sares4.046 86
chains, square surveyor'ssquare feet4,356
chains, surveyor'sfeet66
chains, surveyor'smeters20.116 8
chains, surveyor'srods4
cords of woodcubic feet128
cords of woodcubic meters3.624 556
cords of woodcubic yards4.740 7
cupsliquid ounces (US)8
cupsliters0.236 588 2
degrees Celsiusdegrees Fahrenheitmultiply by 1.8 and add 32
degrees Fahrenheitdegrees Celsiussubtract 32 and divide by 1.8
dekalitersbushels0.283 775 9
dekaliterscubic feet0.353 146 7
dekaliterscubic inches610.237 4
dekalitersdry pints18.161 66
dekalitersdry quarts9.080 829 8
dekalitersliters10
dekaliterspecks1.135 104
drams, avoirdupoisavoirdupois ounces0.062 55
drams, avoirdupoisgrains27.344
drams, avoirdupoisgrams1.771 845 2
drams, troygrains60
drams, troygrams3.887 934 6
drams, troyscruples3
drams, troytroy ounces0.125
drams, liquid (US)cubic inches0.226
drams, liquid (US)liquid drams (British)1.041
drams, liquid (US)liquid ounces0.125
drams, liquid (US)milliliters3.696 69
drams, liquid (US)minims60
fathomsfeet6
fathomsmeters1.828 8
feetcentimeters30.48
feetinches12
feetkilometers0.000 304 8
feetmeters0.304 8
feetstatute miles0.000 189 39
feetyards0.333 333 3
feet, cubicbushels0.803 563 95
feet, cubiccubic decimeters28.316 847
feet, cubiccubic inches1,728
feet, cubiccubic meters0.028 316 846 592
feet, cubiccubic yards0.037 037 04
feet, cubicdry pints51.428 09
feet, cubicdry quarts25.714 05
feet, cubicgallons7.480 519
feet, cubicgills239.376 6
feet, cubicliquid ounces957.506 5
feet, cubicliquid pints59.844 16
feet, cubicliquid quarts29.922 08
feet, cubicliters28.316 846 592
feet, cubicpecks3.214 256
feet, squareacres0.000 022 956 8
feet, squaresquare centimeters929.030 4
feet, squaresquare decimeters9.290 304
feet, squaresquare inches144
feet, squaresquare meters0.092 903 04
feet, squaresquare yards0.111 111 1
furlongsfeet660
furlongsinches7,920
furlongsmeters201.168
furlongsstatute miles0.125
furlongsyards220
gallons, liquid (US)cubic feet0.133 680 6
gallons, liquid (US)cubic inches231
gallons, liquid (US)cubic meters0.003 785 411 784
gallons, liquid (US)cubic yards0.004 951 13
gallons, liquid (US)gills (US)32
gallons, liquid (US)liquid gallons (British)0.832 67
gallons, liquid (US)liquid ounces128
gallons, liquid (US)liquid pints8
gallons, liquid (US)liquid quarts4
gallons, liquid (US)liters3.785 411 784
gallons, liquid (US)milliliters3,785.411 784
gallons, liquid (US)minims61,440
gills (US)centiliters11.829 4
gills (US)cubic feet0.004 177 517
gills (US)cubic inches7.218 75
gills (US)gallons0.031 25
gills (US)gills (British)0.832 67
gills (US)liquid ounces4
gills (US)liquid pints0.25
gills (US)liquid quarts0.125
gills (US)liters0.118 294 118 25
gills (US)milliliters118.294 118 25
gills (US)minims1,920
grainsavoirdupois drams0.036 571 43
grainsavoirdupois ounces0.002 285 71
grainsavoirdupois pounds0.000 142 86
grainsgrams0.064 798 91
grainskilograms0.000 064 798 91
grainsmilligrams64.798 910
grainspennyweights0.042
grainsscruples0.05
grainstroy drams0.016 6
grainstroy ounces0.002 083 33
grainstroy pounds0.000 200 61
gramsavoirdupois drams0.564 383 39
gramsavoirdupois ounces0.035 273 961
gramsavoirdupois pounds0.002 204 622 6
gramsgrains15.432 361
gramskilograms0.001
gramsmilligrams1,000
gramstroy ounces0.032 150 746 6
gramstroy pounds0.002 679 23
hands (height of horse)centimeters10.16
hands (height of horse)inches4
hectaresacres2.471 053 8
hectaressquare feet107,639.1
hectaressquare kilometers0.01
hectaressquare meters10,000
hectaressquare miles0.003 861 02
hectaressquare yards11,959.90
hundredweights, longavoirdupois pounds112
hundredweights, longkilograms50.802 345
hundredweights, longlong tons0.05
hundredweights, longmetric tons0.050 802 345
hundredweights, longshort tons0.056
hundredweights, shortavoirdupois pounds100
hundredweights, shortkilograms45.359 237
hundredweights, shortlong tons0.044 642 86
hundredweights, shortmetric tons0.045 359 237
hundredweights, shortshort tons0.05
inchescentimeters2.54
inchesfeet0.083 333 33
inchesmeters0.025 4
inchesmillimeters25.4
inchesyards0.027 777 78
inches, cubicbushels0.000 465 025
inches, cubiccubic centimeters16.387 064
inches, cubiccubic feet0.000 578 703 7
inches, cubiccubic meters0.000 016 387 064
inches, cubiccubic yards0.000 021 433 47
inches, cubicdry pints0.029 761 6
inches, cubicdry quarts0.014 880 8
inches, cubicgallons0.004 329 0
inches, cubicgills0.138 528 1
inches, cubicliquid ounces0.554 112 6
inches, cubicliquid pints0.034 632 03
inches, cubicliquid quarts0.017 316 02
inches, cubicliters0.016 387 064
inches, cubicmilliliters16.387 064
inches, cubicminims (US)265.974 0
inches, cubicpecks0.001 860 10
inches, squaresquare centimeters6.451 600
inches, squaresquare feet0.006 944 44
inches, squaresquare meters0.000 645 16
inches, squaresquare yards0.000 771 605
kilogramsavoirdupois drams564.383 4
kilogramsavoirdupois ounces35.273 962
kilogramsavoirdupois pounds2.204 622 622
kilogramsgrains15,432.36
kilogramsgrams1,000
kilogramslong tons0.000 984 2
kilogramsmetric tons0.001
kilogramsshort hundredweights0.022 046 23
kilogramsshort tons0.001 102 31
kilogramstroy ounces32.150 75
kilogramstroy pounds2.679 229
kilometersmeters1,000
kilometersstatute miles0.621 371 192
kilometers, squareacres247.105 38
kilometers, squarehectares100
kilometers, squaresquare meters1,000,000
kilometers, squarestatute miles0.386 102 16
knots (nautical mi/hr)kilometers/hour1.852
knots (nautical mi/hr)statute miles/hour1.151
leagues, nauticalkilometers5.556
leagues, nauticalnautical miles3
leagues, statutekilometers4.828 032
leagues, statutestatute miles3
links, square surveyor'ssquare centimeters404.686
links, square surveyor'ssquare inches62.726 4
links, surveyor'scentimeters20.116 8
links, surveyor'schains0.01
links, surveyor'sinches7.92
litersbushels0.028 377 59
literscubic feet0.035 314 67
literscubic inches61.023 74
literscubic meters0.001
literscubic yards0.001 307 95
litersdekaliters0.1
litersdry pints1.816 166
litersdry quarts0.908 082 98
litersgallons0.264 172 052
litersgills (US)8.453 506
litersliquid ounces33.814 02
litersliquid pints2.113 376
litersliquid quarts1.056 688 2
litersmilliliters1,000
literspecks0.113 510 4
meterscentimeters100
metersfeet3.280 839 895
metersinches39.370 079
meterskilometers0.001
metersmillimeters1,000
metersstatute miles0.000 621 371
metersyards1.093 613 298
meters, cubicbushels28.377 59
meters, cubiccubic feet35.314 666 7
meters, cubiccubic inches61,023.744
meters, cubiccubic yards1.307 950 619
meters, cubicgallons264.172 05
meters, cubicliters1,000
meters, cubicpecks113.510 4
meters, squareacres0.000 247 105 38
meters, squarehectares0.000 1
meters, squaresquare centimeters10,000
meters, squaresquare feet10.763 910 4
meters, squaresquare inches1,550.003 1
meters, squaresquare yards1.195 990 046
micronsmeters0.000 001
micronsinches0.000 039 4
milsinches0.001
milsmillimeters0.025 4
miles, nauticalkilometers1.852 0
miles, nauticalstatute miles1.150 779 4
miles, statutecentimeters160,934.4
miles, statutefeet5,280
miles, statutefurlongs8
miles, statuteinches63,360
miles, statutekilometers1.609 344
miles, statutemeters1,609.344
miles, statuterods320
miles, statuteyards1,760
miles, square nauticalsquare kilometers3.429 904
miles, square nauticalsquare statute miles1.325
miles, square statuteacres640
miles, square statutehectares258.998 811 033 6
miles, square statutesections1
miles, square statutesquare feet27,878,400
miles, square statutesquare kilometers2.589 988 110 336
miles, square statutesquare meters2,589,988.110 336
miles, square statutesquare nautical miles0.755 miles
miles, square statutesquare rods102,400
miles, square statutesquare yards3,097,600
milligramsgrains0.015 432 358 35
milliliterscubic inches0.061 023 744
millilitersgallons0.000 264 17
millilitersgills (US)0.008 453 5
millilitersliquid ounces0.033 814 02
millilitersliquid pints0.002 113 4
millilitersliquid quarts0.001 056 7
millilitersliters0.001
millilitersminims16.230 73
millimetersinches0.039 370 078 7
minims (US)cubic inches0.003 759 77
minims (US)gills (US)0.000 520 83
minims (US)liquid ounces0.002 083 33
minims (US)milliliters0.061 611 52
minims (US)minims (British)1.041
ounces, avoirdupoisavoirdupois drams16
ounces, avoirdupoisavoirdupois pounds0.062 5
ounces, avoirdupoisgrains437.5
ounces, avoirdupoisgrams28.349 523 125
ounces, avoirdupoiskilograms0.028 349 523 125
ounces, avoirdupoistroy ounces0.911 458 3
ounces, avoirdupoistroy pounds0.075 954 86
ounces, liquid (US)cubic feet0.001 044 38
ounces, liquid (US)centiliters2.957 35
ounces, liquid (US)cubic inches1.804 687 5
ounces, liquid (US)gallons0.007 812 5
ounces, liquid (US)gills (US)0.25
ounces, liquid (US)liquid drams8
ounces, liquid (US)liquid ounces (British)1.041
ounces, liquid (US)liquid pints0.062 5
ounces, liquid (US)liquid quarts0.031 25
ounces, liquid (US)liters0.029 573 53
ounces, liquid (US)milliliters29.573 529 6
ounces, liquid (US)minims480
ounces, troyavoirdupois drams17.554 29
ounces, troyavoirdupois ounces1.097 143
ounces, troyavoirdupois pounds0.068 571 43
ounces, troygrains480
ounces, troygrams31.103 476 8
ounces, troypennyweights20
ounces, troytroy drams8
ounces, troytroy pounds0.083 333 3
paces (US)centimeters76.2
paces (US)inches30
pecks (US)bushels0.25
pecks (US)cubic feet0.311 114
pecks (US)cubic inches537.605
pecks (US)cubic meters0.008 809 77
pecks (US)cubic yards0.011 522 74
pecks (US)dekaliters0.880 976 75
pecks (US)dry pints16
pecks (US)dry quarts8
pecks (US)liters8.809 767 5
pecks (US)pecks (British)0.968 9
pennyweightsgrains24
pennyweightsgrams1.555 200 84
pennyweightstroy ounces0.05
pints, dry (US)bushels0.015 625
pints, dry (US)cubic feet0.019 444 63
pints, dry (US)cubic inches33.600 312 5
pints, dry (US)dekaliters0.055 061 05
pints, dry (US)dry pints (British)0.968 9
pints, dry (US)dry quarts0.5
pints, dry (US)liters0.550 610 47
pints, liquid (US)cubic feet0.016 710 07
pints, liquid (US)cubic inches28.875
pints, liquid (US)deciliters4.731 76
pints, liquid (US)gallons0.125
pints, liquid (US)gills (US)4
pints, liquid (US)liquid ounces16
pints, liquid (US)liquid pints (British)0.832 67
pints, liquid (US)liquid quarts0.5
pints, liquid (US)liters0.473 176 473
pints, liquid (US)milliliters473.176 473
pints, liquid (US)minims7,680
points (typographical)inches0.013 837
points (typographical)millimeters0.351 459 8
pounds, avoirdupoisavoirdupois drams256
pounds, avoirdupoisavoirdupois ounces16
pounds, avoirdupoisgrains7,000
pounds, avoirdupoisgrams453.592 37
pounds, avoirdupoiskilograms0.453 592 37
pounds, avoirdupoislong tons0.000 446 428 6
pounds, avoirdupoismetric tons0.000 453 592 37
pounds, avoirdupoisquintals0.004 535 92
pounds, avoirdupoisshort tons0.000 5
pounds, avoirdupoistroy ounces14.583 33
pounds, avoirdupoistroy pounds1.215 278
pounds, troyavoirdupois drams210.651 4
pounds, troyavoirdupois ounces13.165 71
pounds, troyavoirdupois pounds0.822 857 1
pounds, troygrains5,760
pounds, troygrams373.241 721 6
pounds, troykilograms0.373 241 721 6
pounds, troypennyweights240
pounds, troytroy ounces12
quarts, dry (US)bushels0.031 25
quarts, dry (US)cubic feet0.038 889 25
quarts, dry (US)cubic inches67.200 625
quarts, dry (US)dekaliters0.110 122 1
quarts, dry (US)dry pints2
quarts, dry (US)dry quarts (British)0.968 9
quarts, dry (US)liters1.101 221
quarts, dry (US)pecks0.125
quarts, dry (US)pints, dry (US)2
quarts, liquid (US)cubic feet0.033 420 14
quarts, liquid (US)cubic inches57.75
quarts, liquid (US)deciliters9.463 53
quarts, liquid (US)gallons0.25
quarts, liquid (US)gills (US)8
quarts, liquid (US)liquid ounces32
quarts, liquid (US)liquid pints (US)2
quarts, liquid (US)liquid quarts (British)0.832 67
quarts, liquid (US)liters0.946 352 946
quarts, liquid (US)milliliters946.352 946
quarts, liquid (US)minims15,360
quintalsavoirdupois pounds220.462 26
quintalskilograms100
quintalsmetric tons0.1
rodsfeet16.5
rodsmeters5.029 2
rodsyards5.5
rods, squareacres0.006 25
rods, squaresquare meters25.292 85
rods, squaresquare yards30.25
scruplesgrains20
scruplesgrams1.295 978 2
scruplestroy drams0.333
sections (US)square kilometers2.589 988 1
sections (US)square statute miles1
spanscentimeters22.86
spansinches9
sterescubic meters1
sterescubic yards1.307 95
tablespoonsmilliliters14.786 76
tablespoonsteaspoons3
teaspoonsmilliliters4.928 922
teaspoonstablespoons0.333 333
ton-miles, longmetric ton-kilometers1.635 169
ton-miles, shortmetric ton-kilometers1.459 972
tons, gross registercubic feet of permanently enclosed space100
tons, gross registercubic meters of permanently enclosed space2.831 684 7
tons, long (deadweight)avoirdupois ounces35,840
tons, long (deadweight)avoirdupois pounds2,240
tons, long (deadweight)kilograms1,016.046 909 8
tons, long (deadweight)long hundredweights20
tons, long (deadweight)metric tons1.016 046 908 8
tons, long (deadweight)short hundredweights22.4
tons, long (deadweight)short tons1.12
tons, metricavoirdupois pounds2,204.623
tons, metrickilograms1,000
tons, metriclong hundredweights19.684 130 3
tons, metriclong tons0.984 206 5
tons, metricquintals10
tons, metricshort hundredweights22.046 23
tons, metricshort tons1.102 311 3
tons, metrictroy ounces32,150.75
tons, net registercubic feet of permanently enclosed space
for cargo and passengers
100
tons, net registercubic meters of permanently enclosed space
for cargo and passengers
2.831 684 7
tons, shippingcubic feet of permanently enclosed cargo space42
tons, shippingcubic meters of permanently enclosed cargo space1.189 307 574
tons, shortavoirdupois pounds2,000
tons, shortkilograms907.184 74
tons, shortlong hundredweights17.857 14
tons, shortlong tons0.892 857 1
tons, shortmetric tons0.907 184 74
tons, shortshort hundredweights20
townships (US)sections36
townships (US)square kilometers93.239 572
townships (US)square statute miles36
yardscentimeters91.44
yardsfeet3
yardsinches36
yardsmeters0.914 4
yardsmiles0.000 568 18
yards, cubicbushels21.696 227
yards, cubiccubic feet27
yards, cubiccubic inches46,656
yards, cubiccubic meters0.764 554 857 984
yards, cubicgallons201.974 0
yards, cubicliters764.554 857 984
yards, cubicpecks86.784 91
yards, squareacres0.000 206 611 6
yards, squarehectares0.000 083 612 736
yards, squaresquare centimeters8,361.273 6
yards, squaresquare feet9
yards, squaresquare inches1,296
yards, squaresquare meters0.836 127 36
yards, squaresquare miles0.000 000 322 830 6