How to Convert Kilocalories to Kilojoules (kcal to kJ)
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 kilojoules by hand, with examples and a quick-reference table.
The conversion
To convert kilocalories to kilojoules, multiply the value by 4.184. To go the other way, divide by the same number (or multiply by 0.2390057361). For a quick estimate, multiply by about 4.2.
Kilojoules = kilocalories × 4.184
Worked examples
- 3 kcal = 12.552 kJ
- 12.5 kcal = 52.3 kJ
- 75 kcal = 313.8 kJ
Kilocalories to Kilojoules table
| Kilocalories | Kilojoules |
|---|---|
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 20 kcal | 83.68 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 |
| 1,000 kcal | 4,184 kJ |
Common questions
Is kcal to kJ 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 Kilojoules 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.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Background
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.
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For any value, use the Kilocalories to Kilojoules Converter or browse all energy converters.
Run your own numbers: Kilocalories to Kilojoules Converter