Example
4.184 kJ
Energy Converter
Convert between joules, calories, kilowatt-hours, BTUs, and more instantly in your browser. Free online energy converter.
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- Value — enter a numeric amount.
- From — enter a choice from the options.
- To — enter a choice from the options.
- Review your results — the key output is highlighted, with supporting figures below.
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Results
Result
| Detail | Value |
|---|---|
| Kilojoules | |
| Kilocalories | |
| Kilowatt-hours |
What is this calculator for?
Convert energy between joules, calories, kilowatt-hours, BTU, and electronvolts.
How to Use This Calculator
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- Value — enter a numeric amount.
- From — enter a choice from the options.
- To — enter a choice from the options.
- Review your results — the key output is highlighted, with supporting figures below.
What You'll Need
- Value
- a numeric amount range 0–∞ · required
- From
- a choice from the options (Joules (J), Kilojoules (kJ), Calories (cal), Kilocalories (kcal), Kilowatt-hours (kWh), Watt-hours (Wh), BTU, Electronvolts (eV)) · optional
- To
- a choice from the options (Joules (J), Kilojoules (kJ), Calories (cal), Kilocalories (kcal), Kilowatt-hours (kWh), Watt-hours (Wh), BTU, Electronvolts (eV)) · optional
About This Calculator
Energy units connect through the joule. 1 calorie = 4.184 J, 1 kWh = 3.6 million J, 1 BTU ≈ 1055 J, and 1 eV is a tiny 1.6×10⁻¹⁹ J.
This converter normalises to joules and reports kilojoules, kilocalories, and kilowatt-hours beside your target unit. It runs entirely in your browser.
Worked Examples
Frequently Asked Questions
Are "food calories" the same as "calories"?
Food calories (Calories with a capital C) are actually kilocalories. One food Calorie = 1 kcal = 1000 small calories. This tool uses the small calorie (cal) and kilocalorie (kcal) units.
How does eV relate to everyday energy?
Electronvolts are tiny units used in atomic and particle physics. Because the values are extremely small, results involving eV may display in scientific notation.