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Energy converters

13 converters. Joules, calories, kilowatt-hours, BTU and foot-pounds, each with the formula and the math worked out with your numbers.

Food & body

Kilocalories to kilojoules kcal → kJ 500 kcal = 2,092 kJ Kilojoules to kilocalories kJ → kcal 2,000 kJ = 478.01 kcal Calories to joules cal → J 100 cal = 418.4 J Joules to calories J → cal 1,000 J = 239.01 cal

Electricity & heating

Kilowatt-hours to BTU kWh → BTU 10 kWh = 34,121.42 BTU BTU to kilowatt-hours BTU → kWh 100,000 BTU = 29.31 kWh Kilowatt-hours to megajoules kWh → MJ 10 kWh = 36 MJ Megajoules to kilowatt-hours MJ → kWh 100 MJ = 27.78 kWh Therms to kilowatt-hours thm → kWh 50 thm = 1,465.36 kWh Kilowatt-hours to therms kWh → thm 1,000 kWh = 34.12 thm Watt-hours to joules Wh → J 10 Wh = 36,000 J

Mechanics

Joules to foot-pounds J → ft·lbf 100 J = 73.76 ft·lbf Foot-pounds to joules ft·lbf → J 100 ft·lbf = 135.58 J

Energy units at a glance

Unit Symbol In joules Defined as
Joule J 1 1 N·m
Kilojoule kJ 1,000 1,000 J
Megajoule MJ 1,000,000 1,000 kJ
Calorie cal 4.184 4.184 J
Kilocalorie kcal 4,184 1,000 cal (food “Calorie”)
Watt-hour Wh 3,600 3,600 J
Kilowatt-hour kWh 3,600,000 3.6 MJ
British thermal unit BTU 1,055.055853 1,055.05585262 J
Therm thm 105,505,585.262 100,000 BTU
Foot-pound ft·lbf 1.355818 1.3558179483314 J