Instant, two-way conversion across common engineering units.
1 °C = 274.15 K(Celsius → Kelvin)
To convert Celsius to kelvin, add 273.15 to the value. Temperature scales use offsets as well as ratios, so a conversion formula is applied rather than a single multiplier.
Temperature scales have different zero points, so the values are matched at the same physical temperature rather than compared by size.
Celsius (°C) is the everyday temperature scale used in most of the world and in building physics.
The kelvin (K) is the SI base unit of thermodynamic temperature.
To convert Celsius to kelvin, add 273.15 to the value. For example, 20 °C equals 293.15 K.
Reverse the formula: subtract 273.15 from the value. The converter above works in both directions, so you can type into either field.
Celsius and Fahrenheit have different zero points, so a simple multiplier cannot work. Each conversion applies both a scale factor and an offset.
Water freezes at 0 °C or 32 °F and boils at 100 °C or 212 °F, so one Celsius degree covers 1.8 Fahrenheit degrees. The scales cross at -40.
Kelvin is the SI unit and starts at absolute zero, so it is used for thermal calculations, U-values and any scientific reporting. Temperature differences are identical in kelvin and Celsius.
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