Convert BTU per Pound °F to Kilojoules per Kilogram Kelvin
1 BTU per pound degree Fahrenheit (BTU/(lb·°F)) = 4.1868 kilojoules per kilogram kelvin (kJ/(kg·K)). 1 kJ/(kg·K) = 0.2388458966 BTU/(lb·°F). Example: 1 BTU/(lb·°F) = 1 × 4.1868 = 4.1868 kJ/(kg·K).
Also searched as BTU/lb°F to kJ/kgK, btu per lb f to kj per kg k and specific heat btu to kj.
1 BTU/(lb·°F) = 4.1868 kJ/(kg·K)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk BTU per pound degree Fahrenheit to kilojoule per kilogram kelvin converter to paste a column from Excel.
How to Convert BTU per Pound °F to Kilojoule per Kilogram Kelvin
- 1 BTU/(lb·°F) = 4.1868 kJ/(kg·K)
- 1 kJ/(kg·K) = 0.2388458966 BTU/(lb·°F)
- Example: convert 1 BTU/(lb·°F) to kJ/(kg·K): 1 BTU/(lb·°F) = 1 × 4.1868 kJ/(kg·K) = 4.1868 kJ/(kg·K)
Formula
kJ/(kg·K) = BTU/(lb·°F) × 4.1868
Derivation from SI units:
- 1 BTU_IT/(lb·°F) = 4186.8 J/(kg·K) exactly (the BTU and the calorie scale the same way).
- 1 kJ/(kg·K) = 1000 J/(kg·K).
- 1 BTU/(lb·°F) = 4186.8 J/(kg·K) ÷ 1000 J/(kg·K) per kJ/(kg·K) = 4.1868 kJ/(kg·K)
Both units are defined exactly, so the factor is exact. BTU per Pound °F definition: BTU per pound degree Fahrenheit; Kilojoule per Kilogram Kelvin definition: kilojoule per kilogram kelvin.
Worked examples
- Water at 1 BTU/(lb·°F) is 4.1868 kJ/(kg·K).
1 BTU/(lb·°F) × 4.1868 = 4.1868 kJ/(kg·K) - Air at 0.24 BTU/(lb·°F) is 1.004832 kJ/(kg·K).
0.24 BTU/(lb·°F) × 4.1868 = 1.004832 kJ/(kg·K)
BTU per Pound °F to Kilojoule per Kilogram Kelvin conversion table
| BTU per Pound °F (BTU/(lb·°F)) | Kilojoules per Kilogram Kelvin (kJ/(kg·K)) |
|---|---|
| 0.03 BTU/(lb·°F) | 0.125604 kJ/(kg·K) |
| 0.09 BTU/(lb·°F) | 0.376812 kJ/(kg·K) |
| 0.11 BTU/(lb·°F) | 0.460548 kJ/(kg·K) |
| 0.12 BTU/(lb·°F) | 0.502416 kJ/(kg·K) |
| 0.2 BTU/(lb·°F) | 0.83736 kJ/(kg·K) |
| 0.24 BTU/(lb·°F) | 1.004832 kJ/(kg·K) |
| 0.45 BTU/(lb·°F) | 1.88406 kJ/(kg·K) |
| 0.5 BTU/(lb·°F) | 2.0934 kJ/(kg·K) |
| 0.8 BTU/(lb·°F) | 3.34944 kJ/(kg·K) |
| 1 BTU/(lb·°F) | 4.1868 kJ/(kg·K) |
Where it's used
Specific heats in BTU/(lb·°F) from US handbooks are converted to kJ/(kg·K) for SI calculations. Multiply by 4.1868 exactly.
BTU per Pound °F to other specific heat capacity units
| Conversion | 1 BTU/(lb·°F) equals |
|---|---|
| BTU per pound degree Fahrenheit to kilojoule per kilogram kelvin | 4.1868 kJ/(kg·K) |
| BTU per pound degree Fahrenheit to joule per kilogram kelvin | 4186.8 J/(kg·K) |
| BTU per pound degree Fahrenheit to calorie per gram degree Celsius | 1 cal/(g·°C) |
| BTU per pound degree Fahrenheit to joule per gram kelvin | 4.1868 J/(g·K) |
| BTU per pound degree Fahrenheit to kilocalorie per kilogram degree Celsius | 1 kcal/(kg·°C) |
Frequently asked questions
How many kJ/(kg·K) is 1 BTU/(lb·°F)?
Exactly 4.1868 kJ/(kg·K), by the definitions of the International Table BTU and calorie.
Why is the factor the same as for calories?
The BTU and the IT calorie were both defined from water’s heat capacity, so 1 BTU/(lb·°F) = 1 kcal/(kg·°C) = 1 cal/(g·°C) = 4.1868 kJ/(kg·K).
How many kilojoules per kilogram kelvin are in 1 BTU per pound degree Fahrenheit?
1 BTU/(lb·°F) = 4.1868 kJ/(kg·K).
How do I convert BTU per pound degree Fahrenheit to kilojoules per kilogram kelvin?
Multiply the value in BTU/(lb·°F) by 4.1868. For example, 1 BTU/(lb·°F) × 4.1868 = 4.1868 kJ/(kg·K).
Is the BTU/(lb·°F) to kJ/(kg·K) conversion exact?
Yes. Both units are defined exactly, and 1 BTU/(lb·°F) is exactly 4.1868 kJ/(kg·K).
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 per pound degree Fahrenheit".
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (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 per Pound °F to Kilojoules per Kilogram Kelvin. Retrieved October 29, 2026, from https://scientificconverters.com/specific-heat/btu-per-pound-fahrenheit-to-kilojoules-per-kilogram-kelvin/
IEEE
Scientific Converters, "Convert BTU per Pound °F to Kilojoules per Kilogram Kelvin," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/specific-heat/btu-per-pound-fahrenheit-to-kilojoules-per-kilogram-kelvin/