ToolnozaIdentify the physical quantity first
Thermal conductivity k describes conduction through a material. In SI its unit is W/(m·K). For steady one-dimensional conduction through a uniform plane layer, the heat-rate magnitude is k × area × temperature difference ÷ thickness. The unit converter changes the representation of k; it does not estimate heat loss by itself.
Do not substitute W/(m²·K), which is a heat-transfer coefficient, or m²·K/W, an area-specific resistance. Even though these quantities describe related heat-transfer behavior, their dimensions differ. Turning conductivity into layer resistance also requires thickness and a suitable physical model.
Convert through a common SI value
The tool multiplies by the source unit’s SI factor and divides by the target factor. For example, 0.04 W/(m·K) is 40 mW/(m·K), or approximately 0.277339 Btu_IT·in/(h·ft²·°F). The factor for W/(cm·K) is 100, not 0.01, because length is in the denominator.
The two BTU-based options differ by a factor of 12: Btu_IT/(h·ft·°F) and Btu_IT·in/(h·ft²·°F). Check the full unit label on a product datasheet. The converter uses International Table BTU and thermochemical kilocalories; other definitions produce slightly different factors.
Keep temperature and material conditions attached
These units use temperature differences. A kelvin difference equals a Celsius-degree difference; Fahrenheit intervals scale by 1.8 without adding 32. Absolute-temperature conversion formulas do not belong in conductivity conversion.
A converted value still refers to the material conditions of the original measurement. Temperature, moisture, density and direction can affect a reported conductivity. Keep these conditions and the source alongside the numerical result, and avoid adding more significant digits than the measurement supports. The displayed extra digits are useful for arithmetic, not evidence of a more precise material property.
How to use the tool
Enter a nonnegative conductivity, select source and target units and compare the equivalent values in the table.
Worked example
1 W/(m·K) ≈ 6.93347 Btu_IT·in/(h·ft²·°F); 1 W/(cm·K) = 100 W/(m·K).
Are W/(m·K) and W/(m·°C) equivalent?
Yes. Conductivity uses temperature differences, so a one-kelvin change equals a one-degree-Celsius change. Do not apply absolute temperature offsets.