Thermal Resistance Converter
Thermal resistance is how many degrees of temperature rise each watt of heat causes — the number on a CPU heatsink's spec sheet, written °C/W. Building work uses the reciprocal-area form instead, in °F·h/BTU. Lower resistance means better heat removal.
6 units supported Base unit kelvin per watt (K/W)
Kelvins per Watt and Degrees Celsius per Watt are the same size, so the value does not change. How this is calculated
About thermal resistance conversion
Thermal Resistance conversion is commonly needed when heatsink selection, semiconductor packaging, and enclosure design. Heatsinks are rated in °C/W, which is identical in size to K/W — a lower number moves heat better.
Convert Kelvin per Watt to other thermal resistance units
1 K/W expressed in every other thermal resistance unit on this site.
- Kelvin per Watt K/W 1
- Degree Celsius per Watt °C/W 1
- Degree Fahrenheit Hour per BTU (IT) °F·h/BTU 0.52752793
- Degree Fahrenheit Hour per BTU (th) °F·h/BTU(th) 0.52717513
- Degree Fahrenheit Second per BTU (IT) °F·s/BTU 1,899.1005
- Degree Fahrenheit Second per BTU (th) °F·s/BTU(th) 1,897.8305
Complete list of thermal resistance units
All 6 units this converter supports, each stated against the kelvin per watt (K/W).
| Unit | Symbol | System | In kelvins per watt | Conversions |
|---|---|---|---|---|
| Kelvin per Watt | K/W | SI | base unit (K/W) | — |
| Degree Celsius per Watt | °C/W | SI | 1 °C/W = 1 K/W | — |
| Degree Fahrenheit Hour per BTU (IT) | °F·h/BTU | Imperial | 1 °F·h/BTU = 1.89563424063 K/W | — |
| Degree Fahrenheit Hour per BTU (th) | °F·h/BTU(th) | Imperial | 1 °F·h/BTU(th) = 1.89690282951 K/W | — |
| Degree Fahrenheit Second per BTU (IT) | °F·s/BTU | Imperial | 1 °F·s/BTU = 0.000526565066841 K/W | — |
| Degree Fahrenheit Second per BTU (th) | °F·s/BTU(th) | Imperial | 1 °F·s/BTU(th) = 0.000526917452641 K/W | — |
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Frequently asked questions
What is the base unit for thermal resistance?
Thermal Resistance conversions on this site are calculated against the kelvin per watt (K/W).
Which thermal resistance units can I convert?
You can convert between 6 units, including kelvin per watt, degree celsius per watt, degree fahrenheit hour per btu (it), degree fahrenheit hour per btu (th), and more.
Where is thermal resistance conversion useful?
It is commonly needed when heatsink selection, semiconductor packaging, and enclosure design.
Does this converter mix measurement systems?
The converter supports SI, Imperial units and keeps their exact definitions separate so results stay accurate.
Related categories
Conversion factors are based on internationally agreed unit definitions. See our methodology and sources for details on how these values are verified.