Watt per Square Metre Kelvin (W/(m²·K))
The watt per square metre kelvin is the SI unit of the heat transfer coefficient h and the overall coefficient (U-value): heat flow per square metre for each kelvin of temperature difference. Free convection in air is about 5–25 W/(m²·K).
Symbol: W/(m²·K) (ASCII: W/(m2*K))
Quantity: heat transfer coefficient (h) and thermal transmittance (U-value)
SI relation: W/(m²·K) is the coherent SI unit of heat transfer coefficient.
Derivation: The SI unit of heat transfer coefficient and thermal transmittance (U-value): heat flow (W) per square metre per kelvin
Exact: yes, by definition
Typical uses
- Building U-values (walls, roofs, windows)
- Convection coefficients and heat exchanger overall U
- Newton’s law of cooling, q = h A ΔT
Convert watts per square metre kelvin to other units
| Conversion | 1 W/(m²·K) equals | Reverse |
|---|---|---|
| watt per square metre kelvin to BTU per hour square foot degree Fahrenheit | 0.1761101837 BTU/(h·ft²·°F) | BTU per hour square foot degree Fahrenheit to watt per square metre kelvin |
| watt per square metre kelvin to kilowatt per square metre kelvin | 0.001 kW/(m²·K) | kilowatt per square metre kelvin to watt per square metre kelvin |
| watt per square metre kelvin to kilocalorie per hour square metre degree Celsius | 0.8598452279 kcal/(h·m²·°C) | kilocalorie per hour square metre degree Celsius to watt per square metre kelvin |
| watt per square metre kelvin to watt per square centimetre kelvin | 0.0001 W/(cm²·K) | watt per square centimetre kelvin to watt per square metre kelvin |
| watt per square metre kelvin to calorie per second square centimetre degree Celsius | 0.00002390057361 cal/(s·cm²·°C) | calorie per second square centimetre degree Celsius to watt per square metre kelvin |
Open the Heat Transfer Coefficient Converter to convert any value between all units.
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.
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). Watt per Square Metre Kelvin (W/(m²·K)). Retrieved October 25, 2026, from https://scientificconverters.com/units/watt-per-square-meter-kelvin/
IEEE
Scientific Converters, "Watt per Square Metre Kelvin (W/(m²·K))," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/units/watt-per-square-meter-kelvin/