How to Convert Kelvin to Celsius

Steps to Convert Kelvin to Celsius

Thermometer
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Kelvin and Celsius are two temperature scales. The size of the "degree" for each scale is the same magnitude, but the Kelvin scale starts at absolute zero, while the Celsius scale sets its zero point at the triple point of water (pretty close to when water freezes). Because Kelvin is an absolute scale, no degree symbol is used following a measurement. Otherwise the two scales are alike. Converting between them only requires basic arithmetic.

Kelvin to Celsius Conversion Formula

Here is the formula to convert Kelvin into Celsius:

°C = K - 273.15

All that is needed to convert Kelvin to Celsius is one simple step.

Take your Kelvin temperature and subtract 273.15. Your answer will be in Celsius. While there is no degree symbol for Kelvin, you need to add the symbol to report a Celsius temperature.

Kelvin to Celsius Conversion Example

How many degrees Celsius is 500K?

°C = K - 273.15
°C = 500 - 273.15
°C = 226.85°

For another example, convert normal body temperature from Kelvin to Celsius. Human body temperature is 310.15 K. Put the value into the equation to solve for degrees Celsius:

°C = K - 273.15
°C = 310.15 - 273.15
human body temperature = 37°C

Celsius to Kelvin Conversion Example

Similarly, it's easy to convert a Celsius temperature to the Kelvin scale. You can either use the formula given above or use:

K = °C + 273.15

For example, convert the boiling point of water to Kelvin.

The boiling point of water is 100°C. Plug the value into the formula:

K = 100 + 273.15 (drop the degree)
K = 373.15

A Note About Absolute Zero

While it's perfectly normal to get negative values for Celsius temperature, the Kelvin scale only goes down to zero. 0K is also known as absolute zero. It is the point at which no further heat can be removed from a system, so there is no lower temperature.

Similarly, this means the lowest possible Celsius temperature you can ever get is -273.15 °C. If you ever perform a calculation that gives you a value lower than that, it's time to go back and check your work. You either have an error or else there is some other problem.

More Temperature Conversion Examples

Although Kelvin and Celsius are the most common temperature scales, it's worth knowing how to convert between these scales and the Fahrenheit temperature scale. Because the degree is a different size in the Fahrenheit scale, the conversion requires more than one step. Here are more conversion examples: