Convert Ergs to BTU
1 erg equals 9.478171203 × 10⁻¹¹ British thermal units (BTU).
1 erg = 9.478171203e-11 BTU
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk erg to BTU converter to paste a column from Excel.
How to Convert Erg to BTU
- 1 erg = 9.478171203 × 10⁻¹¹ BTU
- 1 BTU = 10550558530 erg
- Example: convert 15 erg to BTU: 15 erg = 15 × 9.478171203 × 10⁻¹¹ BTU = 1.42172568 × 10⁻⁹ BTU
Reference conditions. BTU: International Table BTU (BTU_IT), 1055.05585262 J exactly.
Formula
BTU = erg × 9.478171203133 × 10⁻¹¹
or BTU = erg ÷ 10550558526.2
Derivation from SI units:
- 1 erg = 1 dyn·cm = 10⁻⁷ J
- 1 BTU_IT = 1055.05585262 J (exact)
- 1 erg = 1 × 10⁻⁷ J ÷ 1055.05585262 J per BTU = 9.478171203133 × 10⁻¹¹ BTU
Both units are defined exactly, so the factor is exact. Erg definition: erg; BTU definition: British thermal unit.
Worked examples
- A reading of 1000 erg converts to 9.478171203 × 10⁻⁸ BTU.
1000 erg × 9.478171203 × 10⁻¹¹ = 9.478171203 × 10⁻⁸ BTU - A value of 1e6 erg is 0.00009478171203 BTU.
1e6 erg × 9.478171203 × 10⁻¹¹ = 0.00009478171203 BTU
Erg to BTU conversion table
| Ergs (erg) | BTU |
|---|---|
| 1 erg | 9.478171203 × 10⁻¹¹ BTU |
| 10 erg | 9.478171203 × 10⁻¹⁰ BTU |
| 100 erg | 9.478171203 × 10⁻⁹ BTU |
| 1000 erg | 9.478171203 × 10⁻⁸ BTU |
| 10000 erg | 9.478171203 × 10⁻⁷ BTU |
| 1e5 erg | 0.000009478171203 BTU |
| 1e6 erg | 0.00009478171203 BTU |
| 1e7 erg | 0.0009478171203 BTU |
| 1e10 erg | 0.9478171203 BTU |
| 3.828e33 erg | 3.628243937 × 10²³ BTU |
Where it's used
Ergs are used for astrophysics (luminosities in erg/s), 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.
Erg to other energy units
| Conversion | 1 erg equals |
|---|---|
| erg to joule | 1 × 10⁻⁷ J |
| erg to kilojoule | 1 × 10⁻¹⁰ kJ |
| erg to megajoule | 1 × 10⁻¹³ MJ |
| erg to calorie | 2.390057361 × 10⁻⁸ cal |
| erg to kilocalorie | 2.390057361 × 10⁻¹¹ kcal |
| erg to watt-hour | 2.777777778 × 10⁻¹¹ Wh |
| erg to kilowatt-hour | 2.777777778 × 10⁻¹⁴ kWh |
| erg to BTU | 9.478171203 × 10⁻¹¹ BTU |
| erg to therm | 9.48043428 × 10⁻¹⁶ thm |
| erg to electronvolt | 624150907400 eV |
| erg to foot-pound | 7.375621493 × 10⁻⁸ ft·lbf |
Frequently asked questions
How many British thermal units are in 1 erg?
1 erg = 9.478171203 × 10⁻¹¹ BTU.
How do I convert ergs to British thermal units?
Multiply the value in erg by 9.478171203 × 10⁻¹¹, or divide it by 10550558530. For example, 15 erg × 9.478171203 × 10⁻¹¹ = 1.42172568 × 10⁻⁹ BTU.
Is the erg 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, "erg (erg)".
- 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 Ergs to BTU. Retrieved October 17, 2026, from https://scientificconverters.com/energy/ergs-to-btu/
IEEE
Scientific Converters, "Convert Ergs to BTU," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/ergs-to-btu/