Convert BTU to Joules
1 British thermal unit (BTU) equals 1055.055853 joules (J).
1 BTU = 1055.055853 J
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk BTU to joule converter to paste a column from Excel.
How to Convert BTU to Joule
- 1 BTU = 1055.055853 J
- 1 J = 0.0009478171203 BTU
- Example: convert 15 BTU to J: 15 BTU = 15 × 1055.055853 J = 15825.83779 J
Reference conditions. BTU: International Table BTU (BTU_IT), 1055.05585262 J exactly.
Formula
J = BTU × 1055.05585262
Derivation from SI units:
- 1 BTU_IT = 1055.05585262 J (exact)
- 1 J = 1 N·m = 1 W·s = 1 kg·m²·s⁻²
Both units are defined exactly, so the factor is exact. BTU definition: British thermal unit; Joule definition: joule.
Worked examples
- 1 BTU is 1055.055853 J.
1 BTU × 1055.055853 = 1055.055853 J - One therm, 100000 BTU, is 105505585.3 J.
100000 BTU × 1055.055853 = 105505585.3 J
BTU to Joule conversion table
| BTU | Joules (J) |
|---|---|
| 1 BTU | 1055.055853 J |
| 100 BTU | 105505.5853 J |
| 1000 BTU | 1055055.853 J |
| 3412 BTU | 3599850.569 J |
| 5000 BTU | 5275279.263 J |
| 10000 BTU | 10550558.53 J |
| 12000 BTU | 12660670.23 J |
| 24000 BTU | 25321340.46 J |
| 50000 BTU | 52752792.63 J |
| 100000 BTU | 105505585.3 J |
| 1000000 BTU | 1055055853 J |
Where it's used
US heating and fuel data in BTU are converted to joules or kilojoules for SI energy balances. 1 BTU is about 1055 J.
BTU to other energy units
| Conversion | 1 BTU equals |
|---|---|
| BTU to joule | 1055.055853 J |
| BTU to kilojoule | 1.055055853 kJ |
| BTU to megajoule | 0.001055055853 MJ |
| BTU to calorie | 252.1644007 cal |
| BTU to kilocalorie | 0.2521644007 kcal |
| BTU to watt-hour | 0.2930710702 Wh |
| BTU to kilowatt-hour | 0.0002930710702 kWh |
| BTU to therm | 0.00001000238767 thm |
| BTU to electronvolt | 6.585140678 × 10²¹ eV |
| BTU to foot-pound | 778.1692623 ft·lbf |
| BTU to erg | 10550558530 erg |
Frequently asked questions
How many joules is 1 BTU?
The International Table BTU is exactly 1055.05585262 J.
How many joules are in 1 British thermal unit?
1 BTU = 1055.055853 J.
How do I convert British thermal units to joules?
Multiply the value in BTU by 1055.055853. For example, 15 BTU × 1055.055853 = 15825.83779 J.
Is the BTU to J 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, "British thermal unit_IT (Btu_IT)".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
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 BTU to Joules. Retrieved October 17, 2026, from https://scientificconverters.com/energy/btu-to-joules/
IEEE
Scientific Converters, "Convert BTU to Joules," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/btu-to-joules/