Kilocalories to Kilojoules Converter
kcal → kJ · ⚡ Energy
1 Kilocalories = 4.184 Kilojoules
How to convert Kilocalories to Kilojoules
To convert Kilocalories to Kilojoules, multiply the value in Kilocalories by 4.184. For example, 5 kcal = 20.92 kJ.
Converting Kilocalories (kcal) to Kilojoules (kJ) is a frequent need, and the exact relationship is 1 kcal = 4.184 kJ. Whether you're working on a project, checking a specification, or just curious, the calculator above gives you the answer instantly for any value you enter.
Energy conversions appear in nutrition, fitness, physics, utility bills, and engineering. The same quantity of energy can be expressed in joules, calories, kilowatt-hours, or BTU depending on the context.
Understanding Kilocalories and Kilojoules
The joule is the SI unit, but everyday contexts use others: food labels use kilocalories (often just called 'calories'), electricity bills use kilowatt-hours, and heating and cooling systems use BTU (British Thermal Units). One food calorie is actually a kilocalorie — 1,000 of the small physics calories — which is a frequent source of confusion.
How accurate is this conversion?
Energy conversions use standard definitions: 1 calorie = 4.184 joules, 1 kilowatt-hour = 3,600,000 joules, 1 BTU = 1,055.06 joules. These are internationally agreed values, making the conversions exact.
All conversion factors on ClearUnits are based on internationally recognised standards (the International System of Units, SI, and official definitions). Factors are reviewed for accuracy and the calculator uses full-precision values, rounding only the displayed result.
Quick reference: common Kilocalories to Kilojoules values
The most frequently searched conversions are 1 Kilocalories = 4.184 Kilojoules, 5 Kilocalories = 20.92 Kilojoules, 10 Kilocalories = 41.84 Kilojoules, and 100 Kilocalories = 418.4 Kilojoules. The full table further down covers every common value, and the calculator handles any number you need in between.
Pro tip: When comparing appliance efficiency or heating costs, convert everything to kilowatt-hours first, since that's the unit your utility bill uses — it makes the real-world cost immediately comparable.
Kilocalories to Kilojoules — Conversion Table
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 0.1 kcal | 0.4184 kJ |
| 0.25 kcal | 1.046 kJ |
| 0.5 kcal | 2.092 kJ |
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 25 kcal | 104.6 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1000 kcal | 4,184 kJ |