// conversions › 3 · Thermal, Materials & Everyday
Convert thermal conductivity between W/(m·K) and BTU/(hr·ft·°F) via the SI base.
result = value × (from→W/(m·K)) ÷ (to→W/(m·K))
It converts convert thermal conductivity between w/(m·k) and btu/(hr·ft·°f) via the si base by first normalising your value to the SI base unit (watt per metre-kelvin) and then scaling to your chosen target unit. This hub-and-spoke approach guarantees every unit pair is internally consistent.
400 W/(m·K) to BTU/(hr·ft·°F): 400 ÷ 1.7307 ≈ 231.1.
Still air ≈ 0.026, water ≈ 0.6, glass ≈ 1, steel ≈ 50, aluminium ≈ 240, copper ≈ 400 W/(m·K). Copper conducts heat roughly 15,000× better than air — which is why pans are metal and insulation traps air.
Insulation design, electronics cooling and materials selection.
Conversions are exact ratios where the units are defined exactly (most SI and imperial units) and best-available constants otherwise. Extremely large or small magnitudes are shown in general (g) format; round-tripping through the base unit may introduce tiny floating-point differences in the final decimal places.