Engineering Conversion Factors

Engineering Conversion Factors

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This list is based on Basic Units and Derived Units. I use the standard Multiples of Ten where appropriate.


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If you find any errors or can't find some unit; email me and I will include the conversion.



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To Convert To Multiply By

acres ft2 43560

acres m2 4046.9

acres rods2 160

acres hectares .4047

acre feet barrels 7758

acre feet m3 1233.5

angstrom, å cm 10-8

angstrom, å nm 0.1

astronomical unit, AU cm 1.496E13

astronomical unit Tm 0.1496

atmospheres (atm) feet of water 33.94

atmospheres in of Hg 29.92

atmospheres mm of Hg 760

atmospheres psi 14.7

bar atm .98692

bar dyne cm-2 106

bar psi (lb in-2) 14.5038

bar mm Hg 750.06

bar MPa 10-1

barrel (bbl) ft3 5.6146

barrel m3 .15898

barrel gal (US) 42

barrel liter 158.9

BTU Canadian BTU 1.000418022

BTU ISO BTU 1.000527124

BTU cal 251.996

BTU erg 1.055055853 * 1010

BTU joule 1054.35

calorie (gm) (cal) joule 4.184

centimeter (cm) inch 0.39370

cm m 10-2

darcy m2 9.8697E-13

dyne g cm s-2 1

dyne Newton 10-5

erg cal 2.39006E-8

erg dyne cm 1

erg joule 10-7

fathom (fath) ft 6

feet (ft) in 12

feet m 0.3048

furlong yd 220

gallon (US) (gal) in3 231

gallon liter 3.78541

gallon (Imp.) (gal) in3 277.419

gallon liter 4.54608

gamma gauss 10-5

gamma tesla 10-9

gauss tesla 10-4

gram (g) pound 0.0022046

gram kg 10-3

hectare acre 2.47105

hectare cm2 108

horsepower W 745.700

inch (in) cm 2.54

inch (in) mm 25.4

joule (J) erg 107

joule cal 0.239006

kilogram (kg) g 103

kilogram pound 2.20462

kilometer (km) m 103

kilometer ft 3280.84

kilometer mile 0.621371

kilometer hr-1 (kph) mile hr-1 (mph) 0.621371

kilowatt hp 1.34102

knot mph 1.150779

liter cm3 103

liter gal (US) 0.26417

liter in3 61.0237

meter angstrom 1 x 1010

meter ft 3.28084

micron cm 10-4

mile ft 5280

mile km 1.60934

mm Hg dyne cm-2 1333.22

Newton dyne 105

Newton pound (lbf) 0.224809

Newton-meter (torque) foot-pound-force .737562

ounce lb 0.0625

Pascal atmospheres 9.86923 * 10-6

Pascal psi 1.45 * 10-4

Pascal torr 7.501 * 10-3

pint gallon 0.125

poise g cm-1 s-1 1

poise kg m-1 s-1 0.1

pound (lbm) kg 0.453592

pound (lbf) newton 4.4475

rod feet 16.5

quart gallon 0.25

stoke cm2 s-1 1

slug kg 14.594

tesla gauss 104

Torr Millibar 1.333224

Torr Millimeter of Hg 1

ton (long) lb 2240

ton (Metric) lb 2205

ton (Metric) kg 1000

ton (short or net) lb 2000

ton (short or net) kg 907.185

ton (short or net) ton (Metric) .907

watt J s-1 1

yard in 36

yard m 0.9144

year (cal) days 365.242198781

year (cal) s 3.15576 x 107



Basic Units
Length meter m

Time second s

Mass kilogram kg

Temperature Kelvin K

Electrical Current ampere A



Derived Units
Force Newton N kg m s-2

Energy joule J kg m2 s-2

Power watt W kg m2 s-3

Frequency hertz Hz s-1

Charge coulomb C A s

Capacitance farad F C2 s2 kg-1 m-2

Magnetic Induction tesla T kg A-1 s-2



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Multiples of Ten
10-12 pico p

10-9 nano n
10-6 micro µ

10-3 milli m

103 kilo k

106 mega M

109 giga G

1012 tera T



While these multipliers are most often used with metric basic or derived units, the multipliers are sometimes used with english units, creating confusing combinations.
Examples are kip which stands for kilopounds (1000 pounds) and ksi which is a combination of k and psi resulting in thousands of psi.