How to convert kilocalories to joules
To convert kilocalories to joules, multiply by 4,184. Energy conversions connect nutrition, electricity bills, heating systems and physics.
Kilocalorie to Joule conversion table
| Kilocalorie (kcal) | Joule (J) |
|---|---|
| 0.1 kcal | 418.4 J |
| 0.5 kcal | 2,092 J |
| 1 kcal | 4,184 J |
| 2 kcal | 8,368 J |
| 3 kcal | 12,552 J |
| 4 kcal | 16,736 J |
| 5 kcal | 20,920 J |
| 10 kcal | 41,840 J |
| 20 kcal | 83,680 J |
| 25 kcal | 104,600 J |
| 50 kcal | 209,200 J |
| 100 kcal | 418,400 J |
| 500 kcal | 2,092,000 J |
| 1,000 kcal | 4,184,000 J |
About the units
Kilocalorie (kcal)
A kilocalorie (food Calorie) equals 1,000 small calories, or 4,184 joules.
Joule (J)
The joule is the SI unit of energy, the work done by one newton over one meter.
How to use this converter
- Type the number of kilocalories (kcal) in the input box.
- The result in joules appears instantly — no button needed.
- See the same value in every other energy unit just below.
- Use “Swap units” to convert joules back to kilocalories.
When you’ll use the kilocalorie to joule conversion
Converting kilocalories to joules comes up more often than you might expect — for example when understanding your electricity bill in kWh, comparing fuel and battery capacities, or comparing food energy in kcal and kJ. Type your number once and you get the exact answer plus every related unit, so you don’t need to convert twice.
💡 For a quick estimate in your head, multiply by about 4,200 (the exact factor is 4,184).
Watch out for these mix-ups
- Food “Calories” are kilocalories (kcal), not small calories.
- kW is power (a rate); kWh is energy (an amount).
Tips for better results
- Double-check which system a unit belongs to (for example US vs UK gallons).
- Use the swap button to convert in the opposite direction instantly.
- Bookmark the conversions you use most — each pair has its own page.
Frequently asked questions
How many joules are in one kilocalorie?
One kilocalorie equals 4,184 joules. 4,184 is the exact factor used by this converter.
How do I convert kilocalories to joules?
Multiply the value in kilocalories by 4,184. To go the other way, multiply joules by 0.000239005736138.
What is 10 kcal in J?
10 kcal = 41,840 J. Also, 5 kcal = 20,920 J and 100 kcal = 418,400 J.
What is the difference between a kilocalorie and a joule?
A kilocalorie (food Calorie) equals 1,000 small calories, or 4,184 joules. The joule is the SI unit of energy, the work done by one newton over one meter.
Is this tool free and private?
Yes — the Kilocalorie to Joule is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.
Related tools
📬 Get new tools first — free
Join Taurang to hear about new calculators, converters and features. No spam; unsubscribe anytime.