Convert Kilocalories to BTU
1 kilocalorie (kcal) equals 3.965666831 British thermal units (BTU).
1 kcal = 3.965666831 BTU
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk kilocalorie to BTU converter to paste a column from Excel.
How to Convert Kilocalorie to BTU
- 1 kcal = 3.965666831 BTU
- 1 BTU = 0.2521644007 kcal
- Example: convert 15 kcal to BTU: 15 kcal = 15 × 3.965666831 BTU = 59.48500247 BTU
Reference conditions. kcal: Thermochemical kilocalorie (food Calorie), 4184 J exactly. BTU: International Table BTU (BTU_IT), 1055.05585262 J exactly.
Formula
BTU = kcal × 3.965666831391
Derivation from SI units:
- 1 kcal = 1000 cal = 4184 J (exact)
- 1 BTU_IT = 1055.05585262 J (exact)
- 1 kcal = 4184 J ÷ 1055.05585262 J per BTU = 3.965666831391 BTU
Both units are defined exactly, so the factor is exact. Kilocalorie definition: kilocalorie; BTU definition: British thermal unit.
Worked examples
- A reading of 200 kcal converts to 793.1333663 BTU.
200 kcal × 3.965666831 = 793.1333663 BTU - A value of 1500 kcal is 5948.500247 BTU.
1500 kcal × 3.965666831 = 5948.500247 BTU
Kilocalorie to BTU conversion table
| Kilocalories (kcal) | BTU |
|---|---|
| 1 kcal | 3.965666831 BTU |
| 50 kcal | 198.2833416 BTU |
| 100 kcal | 396.5666831 BTU |
| 150 kcal | 594.8500247 BTU |
| 200 kcal | 793.1333663 BTU |
| 250 kcal | 991.4167078 BTU |
| 300 kcal | 1189.700049 BTU |
| 500 kcal | 1982.833416 BTU |
| 1000 kcal | 3965.666831 BTU |
| 1500 kcal | 5948.500247 BTU |
| 2000 kcal | 7931.333663 BTU |
| 2500 kcal | 9914.167078 BTU |
| 3000 kcal | 11897.00049 BTU |
| 3500 kcal | 13879.83391 BTU |
Where it's used
Kilocalories are used for food and diet energy (2000 kcal reference intake), while British thermal units appear in furnace, boiler and fuel ratings in the US. Both measure energy, work and heat, so the conversion is a fixed factor.
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 British thermal units are in 1 kilocalorie?
1 kcal = 3.965666831 BTU.
How do I convert kilocalories to British thermal units?
Multiply the value in kcal by 3.965666831. For example, 15 kcal × 3.965666831 = 59.48500247 BTU.
Is the kcal to BTU 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
- 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)".
- 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, "British thermal unit_IT (Btu_IT)".
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 BTU. Retrieved October 17, 2026, from https://scientificconverters.com/energy/kilocalories-to-btu/
IEEE
Scientific Converters, "Convert Kilocalories to BTU," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/kilocalories-to-btu/