Energy Converter
Joules, calories, kWh, BTU
Enter a value above to see all conversions.
Unit Quick Reference
1 kJ= 1,000 J = 0.2778 Wh = 0.9478 BTU
1 kcal= 4,184 J = 1,000 cal = 3.966 BTU
1 kWh= 3,600,000 J = 3,412 BTU = 860 kcal
1 BTU= 1,055.06 J = 0.2931 Wh = 252 cal
Real-World Energy Examples
1 food Calorie (kcal)≈ 4,184 J
Daily human energy needs≈ 2,000 kcal / 8.37 MJ
60W bulb running 1 hour= 0.06 kWh = 216,000 J
1 litre of gasoline≈ 34.2 MJ = 9.5 kWh
TNT (1 gram)≈ 4,184 J (1 kcal)
FAQ
What is the difference between a calorie and a kilocalorie?
A kilocalorie (kcal) equals 1,000 small calories (cal). Food labels use 'Calories' (capital C) to mean kilocalories. So a 200-Calorie snack is actually 200 kcal = 836,800 J.
How many Joules are in a kWh?
1 kilowatt-hour (kWh) = 3,600,000 Joules (3.6 MJ). This is because 1 watt = 1 J/s, so 1,000 W for 3,600 seconds = 3,600,000 J.