Energy (includes Work) Conversion Calculator

Convert Energy
Value to Convert:

How to Convert Units of Energy

Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:

S * C = E

Where S is our starting value, C is our conversion factor, and E is our end converted result.

To simply convert from any unit into joules, for example, from 100 kilowat-hours, just multiply by the conversion value in the right column in the table below.

100 kW · h * 3600000 [ (J) / ( kW · h) ] = 360000000 J

To convert from J into units in the left column divide by the value in the right column or, multiply by the reciprocal, 1/x.

360000000 J / 3600000  [ (J) / ( kW · h) ] = 100 kW · h

To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into Joules then divide by the factor for B to convert out of Joules.  Or, you can find the single factor you need by dividing the A factor by the B factor.

For example, to convert from kilowat-hours to British Thermal Units you would multiply by 3600000 then divide by 1055.056.  Or, multiply by 3600000/1055.056 = 3412.141156488. So, to convert directly from kW · h to BTU you multiply by 3412.141156488.

Units, symbols and conversion values
used in this energy calculator
To Convert from
and Convert to
( J )
Multiply by
( J / Unit )
British thermal unit [IT] BTUIT joule 1055.056
British thermal unit [th] BTUth joule 1054.35
British thermal unit [mean] BTUmean joule 1055.87
British thermal unit [39°F] BTU39°F joule 1059.67
British thermal unit [59°F] BTU59°F joule 1054.8
British thermal unit [60°F] BTU60°F joule 1054.68
calorie [IT] calIT joule 4.1868
calorie [th] calth joule 4.184
calorie [mean] calmean joule 4.19002
calorie [15°C] cal15°C joule 4.1858
calorie [20°C] cal20°C joule 4.1819
electronvolt eV joule 1.60218E-19
erg erg joule 0.0000001
foot-poundal ft·pdl joule 0.04214011
foot-pound-force ft·lbf joule 1.355818
inch-pound-force in·lbf joule 0.112984829
joule J joule 1
megajoule MJ joule 1000000
kilocalorie [IT] kcalIT joule 4186.8
kilocalorie [th] kcalth joule 4184
kilocalorie [mean] kcalmean joule 4190.02
kilowatt-hour kW·h joule 3600000
quad (IT) quad joule 1.05506E+18
therm (EC) therm joule 105506000
therm (U.S.) therm joule 105480400
ton-of-coal-equivalent TOC joule 29307600000
ton-of-oil-equivalent TOE joule 41868000000
ton-of-TNT-equivalent tTNT joule 4184000000
watt-hour W·h joule 3600
watt-second W·s joule 1

References/ Further Reading

The National Institute of Standards and Technology (NIST) - The NIST Guide for the use of the International System of Units - Appendix B, subsections B.8 Factors for Units Listed Alphabetically and B.9 Factors for units listed by kind of quantity or field of science.

Lide, David R., Daniel (Editor-in-Chief). CRC Handbook of Chemistry and Physics, 89th Edition New York, NY: CRC Press, p. 1-28, 2008.

Wikipedia contributors. "Conversion of units" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 26 Jun. 2011.

How Many? A dictionary of units of measurement at


Cite this content, page or calculator as:

Furey, Edward "Energy Conversion Calculator" From - Online Calculator Resource.