How to Convert Kilocalories to Megajoules (kcal to MJ)
Energy conversions link food labels in kJ and kcal, SP Group bills in kWh and air-conditioner capacity in BTU. This guide shows how to convert kilocalories into megajoules by hand, with examples and a quick-reference table.
The conversion
To convert kilocalories to megajoules, multiply the value by 0.004184. To go the other way, divide by the same number (or multiply by 239.0057361377). For a quick estimate, multiply by about 0.0042.
Megajoules = kilocalories × 0.004184
Worked examples
- 3 kcal = 0.012552 MJ
- 12.5 kcal = 0.0523 MJ
- 75 kcal = 0.3138 MJ
Kilocalories to Megajoules table
| Kilocalories | Megajoules |
|---|---|
| 1 kcal | 0.004184 MJ |
| 2 kcal | 0.008368 MJ |
| 5 kcal | 0.02092 MJ |
| 10 kcal | 0.04184 MJ |
| 20 kcal | 0.08368 MJ |
| 25 kcal | 0.1046 MJ |
| 50 kcal | 0.2092 MJ |
| 100 kcal | 0.4184 MJ |
| 250 kcal | 1.046 MJ |
| 500 kcal | 2.092 MJ |
| 1,000 kcal | 4.184 MJ |
Common questions
Is kcal to MJ exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Megajoules to Kilocalories converter.
Mistakes to avoid
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Background
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the Kilocalories to Megajoules Converter or browse all energy converters.
Run your own numbers: Kilocalories to Megajoules Converter