Convert Joules to Kilocalories
1 joule (J) equals 0.0002390057361 kilocalories (kcal).
1 J = 0.0002390057361 kcal
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk joule to kilocalorie converter to paste a column from Excel.
How to Convert Joule to Kilocalorie
- 1 J = 0.0002390057361 kcal
- 1 kcal = 4184 J
- Example: convert 15 J to kcal: 15 J = 15 × 0.0002390057361 kcal = 0.003585086042 kcal
Reference conditions. kcal: Thermochemical kilocalorie (food Calorie), 4184 J exactly.
Formula
kcal = J ÷ 4184
Derivation from SI units:
- 1 J = 1 N·m = 1 W·s = 1 kg·m²·s⁻²
- 1 kcal = 1000 cal = 4184 J (exact)
Both units are defined exactly, so the factor is exact. Joule definition: joule; Kilocalorie definition: kilocalorie.
Worked examples
- A reading of 250 J converts to 0.05975143403 kcal.
250 J × 0.0002390057361 = 0.05975143403 kcal - A value of 10000 J is 2.390057361 kcal.
10000 J × 0.0002390057361 = 2.390057361 kcal
Joule to Kilocalorie conversion table
| Joules (J) | Kilocalories (kcal) |
|---|---|
| 1 J | 0.0002390057361 kcal |
| 10 J | 0.002390057361 kcal |
| 100 J | 0.02390057361 kcal |
| 250 J | 0.05975143403 kcal |
| 500 J | 0.1195028681 kcal |
| 1000 J | 0.2390057361 kcal |
| 4184 J | 1 kcal |
| 10000 J | 2.390057361 kcal |
| 100000 J | 23.90057361 kcal |
| 1000000 J | 239.0057361 kcal |
| 3600000 J | 860.4206501 kcal |
Where it's used
Joules are used for physics and engineering energy balances, while kilocalories appear in food and diet energy (2000 kcal reference intake). Both measure energy, work and heat, so the conversion is a fixed factor.
Joule to other energy units
| Conversion | 1 J equals |
|---|---|
| joule to kilojoule | 0.001 kJ |
| joule to megajoule | 0.000001 MJ |
| joule to calorie | 0.2390057361 cal |
| joule to kilocalorie | 0.0002390057361 kcal |
| joule to watt-hour | 0.0002777777778 Wh |
| joule to kilowatt-hour | 2.777777778 × 10⁻⁷ kWh |
| joule to BTU | 0.0009478171203 BTU |
| joule to therm | 9.48043428 × 10⁻⁹ thm |
| joule to electronvolt | 6.241509074 × 10¹⁸ eV |
| joule to foot-pound | 0.7375621493 ft·lbf |
| joule to erg | 10000000 erg |
Frequently asked questions
How many kilocalories are in 1 joule?
1 J = 0.0002390057361 kcal.
How do I convert joules to kilocalories?
Multiply the value in J by 0.0002390057361, or divide it by 4184. For example, 15 J × 0.0002390057361 = 0.003585086042 kcal.
Is the J to kcal conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
- 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)".
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 Joules to Kilocalories. Retrieved October 17, 2026, from https://scientificconverters.com/energy/joules-to-kilocalories/
IEEE
Scientific Converters, "Convert Joules to Kilocalories," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/joules-to-kilocalories/