Kilocalories (food Calories) to Kilojoules Converter
1 kcal equals 4.184 kJ, and 1 kJ equals 0.23900574 kcal. Enter a value in either box to convert kilocalories (food calories) to kilojoules and back. Formula: joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J).
· CalcFlow Editorial
1 kcal = 4.184 kJ
Results shown are estimates for informational purposes only. Nothing on CalcFlow is financial, tax, legal, or medical advice. Always consult a qualified professional before making important decisions.
Kilocalories (food Calories) to Kilojoules Conversion Table
| Kilocalories (food Calories) | Kilojoules |
|---|---|
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 2,000 kcal | 8,368 kJ |
Kilojoules to Kilocalories (food Calories) Conversion Table
| Kilojoules | Kilocalories (food Calories) |
|---|---|
| 1 kJ | 0.23900574 kcal |
| 2 kJ | 0.47801147 kcal |
| 5 kJ | 1.1950287 kcal |
| 10 kJ | 2.3900574 kcal |
| 50 kJ | 11.950287 kcal |
| 100 kJ | 23.900574 kcal |
| 500 kJ | 119.50287 kcal |
| 1,000 kJ | 239.00574 kcal |
| 2,000 kJ | 478.01147 kcal |
Worked example: 10 kcal = 41.84 kJ. A 2,000 kcal day is 2,000 x 4.184 = 8,368 kJ. Running a 1.5 kW heater for 2 hours uses 3 kWh, which is 10.8 MJ.
Need other units? Open the full Energy Converter.
Popular Energy Conversions
Formula
joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J)Understanding Energy Conversion
Energy is measured in joules in the SI system. Electricity bills use kilowatt-hours, nutrition labels use kilocalories (called Calories on food packaging), and heating equipment is often rated in BTU. The thermochemical calorie is exactly 4.184 joules, so one food Calorie (a kilocalorie) is 4,184 joules. The electronvolt, now exactly defined, is used for particles and atoms.
Tips and Best Practices
- 1One kilowatt-hour equals 3.6 megajoules, or about 3,412 BTU.
- 2A food Calorie with a capital C is a kilocalorie, or 4.184 kJ.
- 3Divide kilojoules by 4.184 to get kilocalories.
Real-World Example
A 2,000 kcal day is 2,000 x 4.184 = 8,368 kJ. Running a 1.5 kW heater for 2 hours uses 3 kWh, which is 10.8 MJ.
Common Mistakes to Avoid
- Mixing calories (cal) with kilocalories (kcal); there is a factor of 1,000.
- Confusing kilowatts (power) with kilowatt-hours (energy).
- Using a different BTU definition than the one you are comparing with; several exist.
How to Use
- Type a number in the Kilocalories (food Calories) box.
- The Kilojoules result appears instantly; you can also edit the Kilojoules box to convert backwards.
- Use the swap button to reverse the direction and Copy result to copy the answer.
Frequently Asked Questions
How many kilojoules are in 1 kcal?
How many kilocalories (food calories) are in 1 kJ?
What is the formula to convert kilocalories (food calories) to kilojoules?
How many BTU are in a kWh?
Sources: NIST SP 811 (calorie_th = 4.184 J, BTU_IT, foot-pound force); SI Brochure 2019 (elementary charge 1.602176634e-19 C, so 1 eV exact).