Convert Watts per Metre Kelvin to BTU·in/(h·ft²·°F)
1 watt per metre kelvin (W/(m·K)) = 6.933471799 BTU inch per hour square foot degree Fahrenheit (BTU·in/(h·ft²·°F)). 1 BTU·in/(h·ft²·°F) = 0.1442278889 W/(m·K). Example: 0.035 W/(m·K) = 0.035 × 6.933471799 = 0.2426715129 BTU·in/(h·ft²·°F).
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1 W/(m·K) = 6.933471799 BTU·in/(h·ft²·°F)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk watt per metre kelvin to BTU inch per hour square foot degree Fahrenheit converter to paste a column from Excel.
How to Convert Watt per Metre Kelvin to BTU·in/(h·ft²·°F)
- 1 W/(m·K) = 6.933471799 BTU·in/(h·ft²·°F)
- 1 BTU·in/(h·ft²·°F) = 0.1442278889 W/(m·K)
- Example: convert 0.035 W/(m·K) to BTU·in/(h·ft²·°F): 0.035 W/(m·K) = 0.035 × 6.933471799 BTU·in/(h·ft²·°F) = 0.2426715129 BTU·in/(h·ft²·°F)
Formula
BTU·in/(h·ft²·°F) = W/(m·K) × 6.933471798516
Derivation from SI units:
- The SI unit of thermal conductivity: heat flow (W) per metre of thickness per kelvin of temperature difference
- 1 BTU_IT·in/(h·ft²·°F) = 1055.05585262 J × 0.0254 m ÷ (3600 s × 0.09290304 m² × 5/9 K) = 0.1442278889 W/(m·K) (exact)
Both units are defined exactly, so the factor is exact. Watt per Metre Kelvin definition: watt per metre kelvin; BTU·in/(h·ft²·°F) definition: BTU inch per hour square foot degree Fahrenheit.
Worked examples
- Mineral wool with λ = 0.035 W/(m·K) has a k-value of 0.2426715129 BTU·in/(h·ft²·°F).
0.035 W/(m·K) × 6.933471799 = 0.2426715129 BTU·in/(h·ft²·°F) - PIR board at 0.022 W/(m·K) is 0.1525363796 BTU·in/(h·ft²·°F).
0.022 W/(m·K) × 6.933471799 = 0.1525363796 BTU·in/(h·ft²·°F)
Watt per Metre Kelvin to BTU·in/(h·ft²·°F) conversion table
| Watts per Metre Kelvin (W/(m·K)) | BTU·in/(h·ft²·°F) |
|---|---|
| 0.024 W/(m·K) | 0.1664033232 BTU·in/(h·ft²·°F) |
| 0.035 W/(m·K) | 0.2426715129 BTU·in/(h·ft²·°F) |
| 0.04 W/(m·K) | 0.2773388719 BTU·in/(h·ft²·°F) |
| 0.15 W/(m·K) | 1.04002077 BTU·in/(h·ft²·°F) |
| 0.6 W/(m·K) | 4.160083079 BTU·in/(h·ft²·°F) |
| 1 W/(m·K) | 6.933471799 BTU·in/(h·ft²·°F) |
| 1.4 W/(m·K) | 9.706860518 BTU·in/(h·ft²·°F) |
| 16 W/(m·K) | 110.9355488 BTU·in/(h·ft²·°F) |
| 50 W/(m·K) | 346.6735899 BTU·in/(h·ft²·°F) |
| 205 W/(m·K) | 1421.361719 BTU·in/(h·ft²·°F) |
| 401 W/(m·K) | 2780.322191 BTU·in/(h·ft²·°F) |
Where it's used
European λ-values in W/(m·K) are converted to US k-values in BTU·in/(h·ft²·°F) to compare insulation products and work out R-value per inch. Divide by about 0.1442.
Watt per Metre Kelvin to other thermal conductivity units
| Conversion | 1 W/(m·K) equals |
|---|---|
| watt per metre kelvin to BTU inch per hour square foot degree Fahrenheit | 6.933471799 BTU·in/(h·ft²·°F) |
| watt per metre kelvin to BTU per hour foot degree Fahrenheit | 0.5777893165 BTU/(h·ft·°F) |
| watt per metre kelvin to milliwatt per metre kelvin | 1000 mW/(m·K) |
| watt per metre kelvin to kilocalorie per hour metre degree Celsius | 0.8598452279 kcal/(h·m·°C) |
| watt per metre kelvin to watt per centimetre kelvin | 0.01 W/(cm·K) |
| watt per metre kelvin to calorie per second centimetre degree Celsius | 0.002390057361 cal/(s·cm·°C) |
Frequently asked questions
How do I get R-value per inch from λ?
Convert λ to a k-value in BTU·in/(h·ft²·°F), then R per inch = 1/k. λ = 0.035 W/(m·K) gives k ≈ 0.243, so about R-4.1 per inch.
How many BTU inch per hour square foot degree Fahrenheit are in 1 watt per metre kelvin?
1 W/(m·K) = 6.933471799 BTU·in/(h·ft²·°F).
How do I convert watts per metre kelvin to BTU inch per hour square foot degree Fahrenheit?
Multiply the value in W/(m·K) by 6.933471799. For example, 0.035 W/(m·K) × 6.933471799 = 0.2426715129 BTU·in/(h·ft²·°F).
Is the W/(m·K) to BTU·in/(h·ft²·°F) 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, "British thermal unit_IT inch per hour square foot degree Fahrenheit [Btu_IT · in/(h · ft² · °F)]".
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 Watts per Metre Kelvin to BTU·in/(h·ft²·°F). Retrieved October 25, 2026, from https://scientificconverters.com/thermal-conductivity/watts-per-meter-kelvin-to-btu-inch-per-hour-square-foot-fahrenheit/
IEEE
Scientific Converters, "Convert Watts per Metre Kelvin to BTU·in/(h·ft²·°F)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/thermal-conductivity/watts-per-meter-kelvin-to-btu-inch-per-hour-square-foot-fahrenheit/