Conversion Factors

Conversion Factors to SI Units

Google is great for converting units. For example, to convert 10 feet to meters, type "10 ft in m" into google.

Acceleration

1 ft/s² = 0.3048 m/s²
g = 9.807 m/s²

Area

1 acre = 9.807 m/s²
1 ft² = 9.290 x 10^-2 m²
1 in² = 6.45 x 10^-4 m²
1 mi² = 2.59 x 10⁶ m²

Density

1 g/cm³ = 10³ kg/m³

Energy

1 Btu = 1054 J
1 calorie (cal) = 4.184 J
1 electron volt (eV) = 1.602 x 10^-19 J
1 foot pound (ftlb) = 1.356 J
1 kilowatt hour (kWh) = 3.60 x 10⁶ J

Force

1 dyne = 10^-5 N
1 lb = 4.448 N

Length

1 angstrom (Å) = 10^-10 m
1 ft = 0.3048 m
1 in = 2.54 x 10^-2 m
1 light year = 9.461 x 10¹⁵ m
1 mile = 1609 m

Mass

1 atomic mass unit (u) = 1.60606 x 10^-27 kg
1 gram = 10^-3 kg

Power

1 Btu = 1054 W
1 cal/s = 4.184 W
1 ftlb/s = 1.356 W
1 horsepower (hp) = 746 W

Pressure

1 atmosphere (atm) = 1.013 x 10⁵ pascal (Pa)
1 bar = 10⁵ Pa
1 cmHg = 1333 Pa
1 lb/ft² = 47.88 Pa
1 lb/in² (psi) = 6895 Pa
1 N/m² = 1 pascal (Pa)
1 torr = 133.3 Pa

Speed

1 ft/s (fps) = 0.3048 m/s
1 km/h = 0.2778 m/s
1 mi/hr (mph) = 0.44704 m/s

Temperature

T_Kelvin = T_Celsius = 273.15
T_Kelvin = (9/5)*( T_Fahrenheit + 459.67 )
T_Celsius = (5/9)*( T_Fahrenheit - 32)
T_Kelvin = (5/9)*T_Rankine

Time

1 day = 86400 s
1 year = 3.16 x 10⁷ s

Volume

1 ft³ = 2.832 x 10^-2 m³
1 gallon = 3.785 x 10^-5 m³
1 in³ = 1.639 x 10^-5 m³
1 liter = 10^-3 m