Energy Converter
Convert between 9 energy units: joules, calories, watt-hours, electronvolts, BTU and therms, with live results and the exact formula shown.
How energy conversion works
All units convert through joules, the SI unit. Each unit has one fixed factor (1 kWh = 3,600,000 J), so any pair converts in a single step with no chained rounding.
Food calories vs physics calories
Food "calories" are actually kilocalories: 1 food Calorie = 1,000 physics calories = 4.184 kJ. Electricity bills use kWh, heating uses BTU or therms, and particle physics uses electronvolts.