How to calculate energy
Convert to joules first, then to the target unit.
Worked example. 1,000 kJ equals: 239.01 kcal.
Example inputs — Amount: 1,000; From: Kilojoules (kJ); To: Kilocalories / food Calories. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Food 'Calories' (capital C) are kilocalories — 1 food Calorie = 1,000 small calories = 4,184 joules.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
How many kWh is a BTU?
1 kWh ≈ 3,412 BTU — handy for comparing heaters and air conditioners.