Convert Kilocalories to Kilojoules
1 kilocalorie (kcal) equals 4.184 kilojoules (kJ).
1 kcal = 4.184 kJ
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk kilocalorie to kilojoule converter to paste a column from Excel.
How to Convert Kilocalorie to Kilojoule
- 1 kcal = 4.184 kJ
- 1 kJ = 0.2390057361 kcal
- Example: convert 100 kcal to kJ: 100 kcal = 100 × 4.184 kJ = 418.4 kJ
Reference conditions. kcal: Thermochemical kilocalorie (food Calorie), 4184 J exactly.
Formula
kJ = kcal × 4.184
Derivation from SI units:
- 1 kcal = 1000 cal = 4184 J (exact)
- 1 kJ = 10³ J
- 1 kcal = 4184 J ÷ 1000 J per kJ = 4.184 kJ
Both units are defined exactly, so the factor is exact. Kilocalorie definition: kilocalorie; Kilojoule definition: kilojoule.
Worked examples
- A 2000 kcal daily reference intake is 8368 kJ.
2000 kcal × 4.184 = 8368 kJ - A 250 kcal snack provides 1046 kJ.
250 kcal × 4.184 = 1046 kJ
Kilocalorie to Kilojoule conversion table
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 1 kcal | 4.184 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 150 kcal | 627.6 kJ |
| 200 kcal | 836.8 kJ |
| 250 kcal | 1046 kJ |
| 300 kcal | 1255.2 kJ |
| 500 kcal | 2092 kJ |
| 1000 kcal | 4184 kJ |
| 1500 kcal | 6276 kJ |
| 2000 kcal | 8368 kJ |
| 2500 kcal | 10460 kJ |
| 3000 kcal | 12552 kJ |
| 3500 kcal | 14644 kJ |
Where it's used
Food labels in Australia, New Zealand and the EU show kilojoules next to kilocalories. Multiply kcal by 4.184 to get kJ.
Kilocalorie to other energy units
| Conversion | 1 kcal equals |
|---|---|
| kilocalorie to joule | 4184 J |
| kilocalorie to kilojoule | 4.184 kJ |
| kilocalorie to megajoule | 0.004184 MJ |
| kilocalorie to calorie | 1000 cal |
| kilocalorie to watt-hour | 1.162222222 Wh |
| kilocalorie to kilowatt-hour | 0.001162222222 kWh |
| kilocalorie to BTU | 3.965666831 BTU |
| kilocalorie to therm | 0.00003966613703 thm |
| kilocalorie to electronvolt | 2.611447397 × 10²² eV |
| kilocalorie to foot-pound | 3085.960033 ft·lbf |
| kilocalorie to erg | 41840000000 erg |
Frequently asked questions
How many kJ is 1 Calorie?
One food Calorie is one kilocalorie, 4.184 kJ.
How many kilojoules are in 1 kilocalorie?
1 kcal = 4.184 kJ.
How do I convert kilocalories to kilojoules?
Multiply the value in kcal by 4.184. For example, 100 kcal × 4.184 = 418.4 kJ.
Is the kcal to kJ conversion exact?
Yes. Both units are defined exactly, and 1 kcal is exactly 4.184 kJ.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "kilocalorie (thermochemical)".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Kilocalories to Kilojoules. Retrieved October 17, 2026, from https://scientificconverters.com/energy/kilocalories-to-kilojoules/
IEEE
Scientific Converters, "Convert Kilocalories to Kilojoules," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/kilocalories-to-kilojoules/