# Conversion Factors

Length
m cm km
1 meter 1 102 10−3
1 centimeter 10−2 1 10−5
1 kilometer 103 105 1
1 inch $2.540\times {10}^{-2}$ 2.540 $2.540\times {10}^{-5}$
1 foot 0.3048 30.48 $3.048\times {10}^{-4}$
1 mile 1609 $1.609\times {10}^{4}$ 1.609
1 angstrom 10−10
1 fermi 10−15
1 light-year $9.460\times {10}^{12}$
in. ft mi
1 meter 39.37 3.281 $6.214\times {10}^{-4}$
1 centimeter 0.3937 $3.281\times {10}^{-2}$ $6.214\times {10}^{-6}$
1 kilometer $3.937\times {10}^{4}$ $3.281\times {10}^{3}$ 0.6214
1 inch 1 $8.333\times {10}^{-2}$ $1.578\times {10}^{-5}$
1 foot 12 1 $1.894\times {10}^{-4}$
1 mile $6.336\times {10}^{4}$ 5280 1

Area

$1\,{\text{cm}}^{2}=0.155\,{\text{in.}}^{2}$

$1\,{\text{m}}^{2}={10}^{4}\,{\text{cm}}^{2}=10.76\,{\text{ft}}^{2}$

$1\,{\text{in.}}^{2}=6.452\,{\text{cm}}^{2}$

$1\,{\text{ft}}^{2}=144\,{\text{in.}}^{2}=0.0929\,{\text{m}}^{2}$

Volume

$1\,\text{liter}=1000\,{\text{cm}}^{3}={10}^{-3}\,{\text{m}}^{3}=0.03531\,{\text{ft}}^{3}=61.02\,{\text{in.}}^{3}$

$1\,{\text{ft}}^{3}=0.02832\,{\text{m}}^{3}=28.32\,\text{liters}=7.477\,\text{gallons}$

$1\,\text{gallon}=3.788\,\text{liters}$

Time
s min h day yr
1 second 1 $1.667\times {10}^{-2}$ $2.778\times {10}^{-4}$ $1.157\times {10}^{-5}$ $3.169\times {10}^{-8}$
1 minute 60 1 $1.667\times {10}^{-2}$ $6.944\times {10}^{-4}$ $1.901\times {10}^{-6}$
1 hour 3600 60 1 $4.167\times {10}^{-2}$ $1.141\times {10}^{-4}$
1 day $8.640\times {10}^{4}$ 1440 24 1 $2.738\times {10}^{-3}$
1 year $3.156\times {10}^{7}$ $5.259\times {10}^{5}$ $8.766\times {10}^{3}$ 365.25 1
Speed
m/s cm/s ft/s mi/h
1 meter/second 1 102 3.281 2.237
1 centimeter/second 10−2 1 $3.281\times {10}^{-2}$ $2.237\times {10}^{-2}$
1 foot/second 0.3048 30.48 1 0.6818
1 mile/hour 0.4470 44.70 1.467 1

Acceleration

$1\,{\text{m/s}}^{2}=100\,{\text{cm/s}}^{2}=3.281\,{\text{ft/s}}^{2}$

$1\,{\text{cm/s}}^{2}=0.01\,{\text{m/s}}^{2}=0.03281\,{\text{ft/s}}^{2}$

$1\,{\text{ft/s}}^{2}=0.3048\,{\text{m/s}}^{2}=30.48\,{\text{cm/s}}^{2}$

$1\,\text{mi/h}\cdot \text{s}=1.467\,{\text{ft/s}}^{2}$

Mass
kg g slug u
1 kilogram 1 103 $6.852\times {10}^{-2}$ $6.024\times {10}^{26}$
1 gram 10−3 1 $6.852\times {10}^{-5}$ $6.024\times {10}^{23}$
1 slug 14.59 $1.459\times {10}^{4}$ 1 $8.789\times {10}^{27}$
1 atomic mass unit $1.661\times {10}^{-27}$ $1.661\times {10}^{-24}$ $1.138\times {10}^{-28}$ 1
1 metric ton 1000
Force
N dyne lb
$1$ newton 1 105 0.2248
$1$ dyne 10−5 1 $2.248\times {10}^{-6}$
$1$ pound 4.448 $4.448\times {10}^{5}$ 1
Pressure
Pa dyne/cm2 atm cmHg lb/in.2
*Where the acceleration due to gravity is $9.80665\,{\text{m/s}}^{2}$ and the temperature is $0^\circ\text{C}$
1 pascal 1 10 $9.869\times {10}^{-6}$ $7.501\times {10}^{-4}$ $1.450\times {10}^{-4}$
1 dyne/centimeter2 10−1 1 $9.869\times {10}^{-7}$ $7.501\times {10}^{-5}$ $1.450\times {10}^{-5}$
1 atmosphere $1.013\times {10}^{5}$ $1.013\times {10}^{6}$ 1 76 14.70
1 centimeter mercury* $1.333\times {10}^{3}$ $1.333\times {10}^{4}$ $1.316\times {10}^{-2}$ 1 0.1934
1 pound/inch2 $6.895\times {10}^{3}$ $6.895\times {10}^{4}$ $6.805\times {10}^{-2}$ 5.171 1
1 bar 105
1 torr 1 (mmHg)
Work, Energy, Heat
J erg ft.lb
1 joule 1 107 0.7376
1 erg 10−7 1 $7.376\times {10}^{-8}$
1 foot-pound 1.356 $1.356\times {10}^{7}$ 1
1 electron-volt $1.602\times {10}^{-19}$ $1.602\times {10}^{\text{-12}}$ $1.182\times {10}^{-19}$
1 calorie 4.186 $4.186\times {10}^{7}$ 3.088
1 British thermal unit $1.055\times {10}^{3}$ $1.055\times {10}^{10}$ $7.779\times {10}^{2}$
1 kilowatt-hour $3.600\times {10}^{6}$
eV cal Btu
1 joule $6.242\times {10}^{18}$ 0.2389 $9.481\times {10}^{-4}$
1 erg $6.242\times {10}^{11}$ $2.389\times {10}^{-8}$ $9.481\times {10}^{-11}$
1 foot-pound $8.464\times {10}^{18}$ 0.3239 $1.285\times {10}^{-3}$
1 electron-volt 1 $3.827\times {10}^{-20}$ $1.519\times {10}^{-22}$
1 calorie $2.613\times {10}^{19}$ 1 $3.968\times {10}^{-3}$
1 British thermal unit $6.585\times {10}^{21}$ $2.520\times {10}^{2}$ 1

Power

$1\,\text{W}=1\,\text{J/s}$

$1\,\text{hp}=746\,\text{W}=550\,\text{ft}\cdot \text{lb/s}$

$1\,\text{Btu/h}=0.293\,\text{W}$

Angle

$1\,\text{rad}=57.30^\circ=180^\circ\text{/}\text{π}$

$1^\circ=0.01745\,\text{rad}=\text{π}\text{/}180\,\text{rad}$

$1\,\text{revolution}=360^\circ=2\text{π}\,\text{rad}$

$1\,\text{rev/min}(\text{rpm})=0.1047\,\text{rad/s}$