Unit Conversion Factors
This page provides conversion tables for common engineering units.
Contents
Unit Conversion Tables
In the following tables, a number in bold and blue indicates an exact conversion value.
Length
A table of conversion factors between common length units is provided below:
in | ft | yd | mi | NM | m | mm | km | |
---|---|---|---|---|---|---|---|---|
1 in (inch) = | 1 | 0.08333333 | 0.02777778 | 1.578283 E-5 | 1.371490 E-5 | 0.0254 | 25.4 | 2.54 E-5 |
1 ft (foot) = | 12 | 1 | 0.3333333 | 1.893939 E-4 | 1.645788 E-4 | 0.3048 | 304.8 | 3.048 E-4 |
1 yd (yard) = | 36 | 3 | 1 | 5.681818 E-4 | 4.937365 E-4 | 0.9144 | 914.4 | 9.144 E-4 |
1 mi (mile) = | 63360 | 5280 | 1760 | 1 | 0.8689762 | 1609.344 | 1.609344 E6 | 1.609344 |
1 NM (nautical mile) = | 72913.38588 | 6076.11549 | 2025.37183 | 1.150779 | 1 | 1852.000 | 1.852000 E6 | 1.852000 |
1 m (meter) = | 39.37008 | 3.280840 | 1.093613 | 6.213712 E-4 | 5.399568 E-4 | 1 | 1000 | 0.001 |
1 mm (millimeter) = | 0.03937008 | 3.280840 E-3 | 1.093613 E-3 | 6.213712 E-7 | 5.399568 E-7 | 0.001 | 1 | 1 E-6 |
1 km (kilometer) = | 39370.08 | 3280.840 | 1093.613 | 0.6213712 | 0.5399568 | 1000 | 1 E6 | 1 |
Area
A table of conversion factors between common area units is provided below:
in2 | ft2 | mi2 | acre | m2 | cm2 | mm2 | |
---|---|---|---|---|---|---|---|
1 in2 (inch2) = | 1 | 6.944444 E-3 | 2.490977 E-10 | 1.594225 E-7 | 6.4516 E-4 | 6.4516 | 645.16 |
1 ft2 (foot2) = | 144 | 1 | 3.587006 E-8 | 2.295684 E-5 | 0.09290304 | 929.0304 | 9.290304 E4 |
1 mi2 (mile2) = | 4.0144896 E9 | 2.78784 E7 | 1 | 640 | 2.589988 E6 | 2.589988 E10 | 2.589988 E12 |
1 acre = | 6.27264 E6 | 43560 | 1.5625 E-3 | 1 | 4.046856 E3 | 4.046856 E7 | 4.046856 E9 |
1 m2 (meter2) = | 1.550003 E3 | 10.76391 | 3.861022 E-7 | 2.471054 E-4 | 1 | 1 E4 | 1 E6 |
1 cm2 (centimeter2) = | 0.1550003 | 1.076391 E-3 | 3.861022 E-11 | 2.471054 E-8 | 0.0001 | 1 | 100 |
1 mm2 (millimeter2) = | 1.550003 E-3 | 1.076391 E-5 | 3.861022 E-13 | 2.471054 E-10 | 1 E-6 | 0.01 | 1 |
Volume
A table of conversion factors between common volume units is provided below:
in3 | ft3 | gal | pint | cm3 | m3 | L | |
---|---|---|---|---|---|---|---|
1 in3 (cubic inch) = | 1 | 5.787037 E-4 | 4.329004 E-3 | 0.03463203 | 16.387064 | 1.638706 E-5 | 0.01638706 |
1 ft3 (cubic foot) = | 1728 | 1 | 7.480519 | 59.84416 | 28316.85 | 0.02831685 | 28.31685 |
1 gal (gallon) = | 231 | 0.1336806 | 1 | 8 | 3785.412 | 3.785412 E-3 | 3.785412 |
1 pint = | 28.875 | 0.01671007 | 0.125 | 1 | 473.1765 | 4.731765 E-4 | 0.4731765 |
1 cm3 (cubic centimeter) (CC) = | 0.06102374 | 3.531467 E-5 | 2.641720 E-4 | 0.0021134 | 1 | 1 E-6 | 0.001 |
1 m3 (cubic meter) = | 61023.74 | 35.31467 | 264.1720 | 2113.376 | 1 E6 | 1 | 1000 |
1 L (liter) = | 61.02374 | 0.03531467 | 0.2641720 | 2.113376 | 1000 | 0.001 | 1 |
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Mass
A table of conversion factors between common mass units is provided below:
lbm | slug | oz | short ton | long ton | kg | tonne | |
---|---|---|---|---|---|---|---|
1 lbm (pound-mass) = | 1 | 0.03108095 | 16 | 0.0005 | 4.464286 E-4 | 0.45359237 | 4.5359237 E-4 |
1 slug = | 32.17405 | 1 | 514.7848 | 0.01608702 | 0.01436341 | 14.59390 | 0.01459390 |
1 oz (avoirdupois ounce) = | 0.0625 | 1.942559 E-3 | 1 | 3.125 E-5 | 2.790179 E-5 | 0.02834952 | 2.834952 E-5 |
1 ton (short) = | 2000 | 62.16190 | 32000 | 1 | 0.8928571 | 907.18474 | 0.90718474 |
1 ton (long) = | 2240 | 69.62133 | 35840 | 1.12 | 1 | 1016.047 | 1.016047 |
1 kg (kilogram) = | 2.204623 | 0.06852177 | 35.27396 | 1.102311 E-3 | 9.842065 E-4 | 1 | 0.001 |
1 tonne (metric ton) = | 2204.623 | 68.52177 | 3.527396 E4 | 1.102311 | 0.9842065 | 1000 | 1 |
- NOTE: The Avoirdupois ounce is what is typically used in engineering work, as opposed to the Troy ounce (which is used for weighing gold and silver).
Density
A table of conversion factors between common density units is provided below:
lbm/in3 | lbm/ft3 | slug/ft3 | g/cm3 | kg/m3 | |
---|---|---|---|---|---|
1 lbm/in3 = | 1 | 1728 | 53.70788 | 27.67990 | 27679.90 |
1 lbm/ft3 = | 5.787037 E-4 | 1 | 0.03108095 | 0.01601846 | 16.01846 |
1 slug/ft3 = | 0.01861924 | 32.17405 | 1 | 0.5153788 | 515.3788 |
1 g/cm3 = | 0.03612729 | 62.42796 | 1.940320 | 1 | 1000 |
1 kg/m3 = | 3.612729 E-5 | 0.06242796 | 1.940320 E-3 | 0.001 | 1 |
Force
A table of conversion factors between common force units is provided below:
lbf | kip | N | gf | kgf | dyne | |
---|---|---|---|---|---|---|
1 lbf (pound-force) = | 1 | 0.001 | 4.448222 | 453.5924 | 0.4535924 | 4.448222 E5 |
1 kip (1000 lbf) = | 1000 | 1 | 4.448222 E3 | 4.535924 E5 | 453.5924 | 4.448222 E8 |
1 N (Newton) = | 0.2248089 | 2.248089 E-4 | 1 | 101.9716 | 0.1019716 | 1 E5 |
1 gf (gram-force) = | 2.204623 E-3 | 2.204623 E-6 | 9.80665 E-3 | 1 | 0.001 | 980.665 |
1 kgf (kilogram-force) = | 2.204623 | 2.204623 E-3 | 9.80665 | 1000 | 1 | 9.80665 E5 |
1 dyne = | 2.248089 E-6 | 2.248089 E-9 | 1 E-5 | 1.019716 E-3 | 1.019716 E-6 | 1 |
- NOTE: A kilopond (kp) is another term for kilogram-force (kgf).
Moment & Torque
A table of conversion factors between common units of moment and torque is provided below:
in•lbf | ft•lbf | N•m | kgf•m | dyne•cm | |
---|---|---|---|---|---|
1 in•lbf (inch-pound) = | 1 | 0.08333333 | 0.1129848 | 0.01152125 | 1.129848 E6 |
1 ft•lbf (foot-pound) = | 12 | 1 | 1.355818 | 0.1382550 | 1.355818 E7 |
1 N•m (Newton-meter) = | 8.850746 | 0.7375621 | 1 | 0.1019716 | 1 E7 |
1 kgf•m (kilogram-force-meter) = | 86.79617 | 7.233014 | 9.80665 | 1 | 9.80665 E7 |
1 dyne•cm (dyne-centimeter) = | 8.850746 E-7 | 7.375621 E-8 | 1 E-7 | 1.019716 E-8 | 1 |
Pressure & Stress
A table of conversion factors between common units of pressure and stress is provided below:
psi | ksi | psf | Pa | kPa | MPa | |
---|---|---|---|---|---|---|
1 psi (lbf/in2) = | 1 | 0.001 | 144 | 6894.757 | 6.894757 | 6.894757 E-3 |
1 ksi (1000 psi) = | 1000 | 1 | 144000 | 6.894757 E6 | 6894.757 | 6.894757 |
1 psf (lbf/ft2) = | 6.944444 E-3 | 6.944444 E-6 | 1 | 47.88026 | 0.04788026 | 4.788026 E-5 |
1 Pa (Pascal) = | 1.450377 E-4 | 1.450377 E-7 | 0.02088543 | 1 | 0.001 | 1 E-6 |
1 kPa (kilopascal) = | 0.1450377 | 1.450377 E-4 | 20.88543 | 1000 | 1 | 0.001 |
1 MPa (megapascal) = | 145.0377 | 0.1450377 | 20885.43 | 1 E6 | 1000 | 1 |
- NOTE: A Pascal is a derived unit equal to 1 N/m2.
Fluid Pressure
A table of conversion factors between common fluid pressure units is provided below:
psi | psf | kPa | atm | bar | in Hg | mm Hg | in H2O | mm H2O | |
---|---|---|---|---|---|---|---|---|---|
1 psi (lbf/in2) = | 1 | 144 | 6.894757 | 0.06804596 | 0.06894757 | 2.036020 | 51.71492 | 27.67990 | 703.0696 |
1 psf (lbf/ft2) = | 6.944444 E-3 | 1 | 0.04788026 | 4.725414 E-4 | 4.788026 E-4 | 0.01413903 | 0.3591314 | 0.1922216 | 4.882428 |
1 kPa (kilopascal) = | 0.1450377 | 20.88543 | 1 | 9.869233 E-3 | 0.01 | 0.2952998 | 7.500615 | 4.014631 | 101.9716 |
1 atm (atmosphere) = | 14.69595 | 2116.217 | 101.325 | 1 | 1.01325 | 29.92125 | 759.9998 | 406.7825 | 10332.27 |
1 bar = | 14.50377 | 2088.543 | 100 | 0.9869233 | 1 | 29.52998 | 750.0615 | 401.4631 | 10197.16 |
1 in Hg (inches of mercury) = | 0.4911542 | 70.72620 | 3.386389 | 0.03342106 | 0.03386389 | 1 | 25.4 | 13.59510 | 345.3156 |
1 mm Hg (mm of mercury) = | 0.01933678 | 2.784496 | 0.1333224 | 1.315790 E-3 | 1.333224 E-3 | 0.03937008 | 1 | 0.5352402 | 13.59510 |
1 in H2O (inches of water) = | 0.03612729 | 5.202330 | 0.2490889 | 2.458316 E-3 | 2.490889 E-3 | 0.07355591 | 1.868320 | 1 | 25.4 |
1 mm H2O (mm of water) = | 1.422334 E-3 | 0.2048161 | 9.80665 E-3 | 9.678411 E-5 | 9.80665 E-5 | 2.895902 E-3 | 0.07355591 | 1.868320 | 1 |
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Velocity (Linear)
A table of conversion factors between common velocity units is provided below:
ft/s | ft/min | mph | m/s | kph | knot | mach | |
---|---|---|---|---|---|---|---|
1 ft/s = | 1 | 60 | 0.6818182 | 0.3048 | 1.09728 | 0.5924838 | 8.886297 E-4 |
1 ft/min = | 0.01666667 | 1 | 0.01136364 | 0.00508 | 0.018288 | 9.874730 E-3 | 1.481050 E-5 |
1 mph (miles/hour) = | 1.466667 | 88 | 1 | 0.44704 | 1.609344 | 0.8689762 | 1.303324 E-3 |
1 m/s = | 3.280840 | 196.8504 | 2.236936 | 1 | 3.6 | 1.943844 | 2.915452 E-3 |
1 kph (kilometers/hour) = | 0.9113444 | 54.68066 | 0.6213712 | 0.2777778 | 1 | 0.5399568 | 8.098477 E-4 |
1 knot = | 1.687810 | 101.2686 | 1.150779 | 0.5144444 | 1.852 | 1 | 1.499838 E-3 |
1 mach = | 1125.328 | 67519.69 | 767.2691 | 343 | 1234.800 | 666.7387 | 1 |
NOTES:
- A knot is a nautical mile per hour.
- Mach 1 is equal to the speed of sound, which is 343 m/s in dry air at 20 °C (68 °F). The speed of sound varies depending on the medium (substance) the sound is travelling through and the temperature.
Acceleration (Linear)
A table of conversion factors between common acceleration units is provided below:
g | in/s2 | ft/s2 | m/s2 | |
---|---|---|---|---|
1 g = | 1 | 386.0886 | 32.17405 | 9.80665 |
1 in/s2 = | 2.590079 E-3 | 1 | 0.08333333 | 0.0254 |
1 ft/s2 = | 0.03108095 | 12 | 1 | 0.3048 |
1 m/s2 = | 0.1019716 | 39.37008 | 3.280840 | 1 |
- NOTE: 1 g is the acceleration due to gravity.
Angular Velocity
A table of conversion factors between common angular velocity units is provided below:
rad/sec | deg/sec | rev/sec | rpm (rev/min) | |
---|---|---|---|---|
1 rad/sec = | 1 | |||
1 deg/sec = | 1 | 1/360 | 1/6 | |
1 rev/sec = | 2π | 360 | 1 | 60 |
1 rpm (rev/min) = | 6 | 1/60 | 1 |
Volumetric Flow Rate
A table of conversion factors between common volumetric flow rate units is provided below:
in3/s | ft3/s | ft3/min | gpm | m3/s | L/s | |
---|---|---|---|---|---|---|
1 in3/s = | 1 | 5.787037 E-4 | 0.03472222 | 0.2597402 | 1.638706 E-5 | 0.01638706 |
1 ft3/s = | 1728 | 1 | 60 | 448.8311 | 0.02831685 | 28.31685 |
1 ft3/min = | 28.8 | 0.01666667 | 1 | 7.480519 | 4.719474 E-4 | 0.4719474 |
1 gpm (gal/min) (US) = | 3.850000 | 2.228009 E-3 | 0.1336806 | 1 | 6.309020 E-5 | 0.06309020 |
1 m3/s = | 61023.74 | 35.31467 | 2118.880 | 15850.32 | 1 | 1000 |
1 L/s = | 61.02374 | 0.03531467 | 2.118880 | 15.85032 | 0.001 | 1 |
Energy & Work
A table of conversion factors between common units of energy and work is provided below:
ft•lbf | Btu | J (N•m) | kJ | kW•hr | kcal | eV | |
---|---|---|---|---|---|---|---|
1 ft•lbf (foot-pound) = | 1 | 1.285067 E-3 | 1.355818 | 1.355881 E-3 | 3.766161 E-7 | 3.238316 E-4 | 8.46235 E18 |
1 Btu (British thermal unit) = | 778.1693 | 1 | 1055.056 | 1.055056 | 2.930711 E-4 | 0.2519958 | 6.58514 E21 |
1 J (Joule) (N•m) = | 0.7375621 | 9.478171 E-4 | 1 | 0.001 | 2.777778 E-7 | 2.388459 E-4 | 6.24151 E18 |
1 kJ (kilojoule) = | 737.5621 | 0.9478171 | 1000 | 1 | 2.777778 E-4 | 0.2388459 | 6.24151 E21 |
1 kW•hr (kilowatt-hour) = | 2.655224 E6 | 3412.142 | 3.6 E6 | 3600 | 1 | 859.8452 | 2.24694 E25 |
1 kcal (kilocalorie) = | 3088.025 | 3.968321 | 4186.8 | 4.1868 | 1.163 E-3 | 1 | 2.61320 E22 |
1 eV (electron volt) = | 1.18170 E-19 | 1.51857 E-22 | 1.60218 E-19 | 1.60218 E-22 | 4.45048 E-26 | 3.82673 E-23 | 1 |
- NOTE: The units of Joule and N•m are equivalent and are both commonly used to express quantities of energy and work.
Power
A table of conversion factors between common power units is provided below:
ft•lbf/s | ft•lbf/min | hp | kW | Btu/s | Btu/min | Btu/hr | |
---|---|---|---|---|---|---|---|
1 ft•lbf/s = | 1 | 60 | 1.818182 E-3 | 1.355818 E-3 | 1.285067 E-3 | 0.0771040 | 4.626243 |
1 ft•lbf/min = | 0.01666667 | 1 | 3.030303 E-5 | 2.259697 E-5 | 2.141779 E-5 | 1.285067 E-3 | 0.0771040 |
1 hp (horsepower) = | 550 | 33000 | 1 | 0.7456999 | 0.7067871 | 42.40723 | 2544.434 |
1 kW (kilowatt) = | 737.5621 | 44253.73 | 1.341022 | 1 | 0.9478171 | 56.86903 | 3412.142 |
1 Btu/s = | 778.1693 | 46690.16 | 1.414853 | 1.055056 | 1 | 60 | 3600 |
1 Btu/min = | 12.96949 | 778.1693 | 0.02358089 | 0.01758426 | 0.01666667 | 1 | 60 |
1 Btu/hr = | 0.2161581 | 12.96949 | 3.930148 E-4 | 2.930711 E-4 | 2.777778 E-4 | 0.01666667 | 1 |
- NOTE: A refrigeration ton is an important unit in HVAC that is not given in the table above. 1 refrigeration ton = 200 Btu/min = 12,000 Btu/hr = 3.516853 kW
Stress Intensity
Stress intensity is an important quantity in fracture mechanics. Conversions between the most common units are given in the table below:
ksi√in | MPa√m | |
---|---|---|
1 ksi√in = | 1 | 1.098843 |
1 MPa√m = | 0.9100477 | 1 |
Temperature
A table of conversions between common temperature units is provided below:
T | ΔT | |
---|---|---|
°C to °F (Celsius to Fahrenheit): | ||
°F to °R (Fahrenheit to Rankine): | ||
°C to K (Celsius to Kelvin): |
References
- "Guide for the Use of the International System of Units (SI)," National Institute of Standards and Technology (NIST), 2008.
- Machinery's Handbook, 27th Ed., Industrial Press Inc., 2004.