And this is how you do it. To get the Kelvin temperature, you take the Celsius temperature and you add 273.15 to it. For example, if our Celsius temperature is ten degrees Celsius, I simply add 273.15 and I get 283.15 Kelvin. That's our temperature in Kelvin. So let's think of an example where Charles Law is evident. So suppose it's someone's birthday and it's winter.