Unit converter
Thermal conductivity.
Convert BTU/(h·ft·°F) to W/(m·K), or pick any of the 2 units in the menus. Type in either box and the other follows. How readily a material carries heat — mineral wool is about 0.04 W/(m·K) and copper about 400.
| BTU/(h·ft·°F) | W/(m·K) |
|---|---|
| 1 BTU/(h·ft·°F) | 1.73073 W/(m·K) |
| 2 BTU/(h·ft·°F) | 3.46147 W/(m·K) |
| 3 BTU/(h·ft·°F) | 5.1922 W/(m·K) |
| 4 BTU/(h·ft·°F) | 6.92294 W/(m·K) |
| 5 BTU/(h·ft·°F) | 8.65367 W/(m·K) |
| 10 BTU/(h·ft·°F) | 17.3073 W/(m·K) |
| 15 BTU/(h·ft·°F) | 25.961 W/(m·K) |
| 20 BTU/(h·ft·°F) | 34.6147 W/(m·K) |
| 25 BTU/(h·ft·°F) | 43.2684 W/(m·K) |
| 50 BTU/(h·ft·°F) | 86.5367 W/(m·K) |
| 75 BTU/(h·ft·°F) | 129.805 W/(m·K) |
| 100 BTU/(h·ft·°F) | 173.073 W/(m·K) |
| 250 BTU/(h·ft·°F) | 432.684 W/(m·K) |
| 500 BTU/(h·ft·°F) | 865.367 W/(m·K) |
| 1000 BTU/(h·ft·°F) | 1730.73 W/(m·K) |
- Every unit in the menus is defined against W/(m·K), so any pairing converts by the same single route.
Definitions
- BTU per hour per foot per degree Fahrenheit is the US building-industry equivalent, 1.730 73 W/(m·K).
- Watts per metre kelvin is the SI measure of how readily a material conducts heat. Mineral wool is about 0.04; copper is about 400.
- Every unit here is defined against the W/(m·K).
- Every unit in the menus is exact by definition, so the only rounding on this page is the one you choose for the display.
How it works
Every value is converted into watts per metre kelvin and then back out into the unit you asked for. One route covers every pairing in the menus, so an unusual combination is no less accurate than a common one, and adding a unit affects only that unit.
Both boxes are live. Whichever one you last typed in is the source, changing either menu recalculates straight away, and Swap exchanges the units and the values so the number you are reading stays where you are looking.
Display precision sets a maximum number of significant figures and trims trailing zeroes, so it changes what you see and never what was calculated. The editable box always holds a plain number at full working precision, so you can carry on from either side.
Common questions this answers: how many watts per metre kelvin in a btu per hour foot degree fahrenheit (1.73073), how many BTU per hour per foot per degree Fahrenheit in a watt per metre kelvin (0.577789), and what 1 BTU/(h·ft·°F) is in watts per metre kelvin (1.73073 W/(m·K)).
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