Depending on where you live in the world, you either use the Fahrenheit or the Celsius temperature scale. Converting between the two is easier than you may expect. A couple of simple formulas can help you estimate or exactly convert between the temperature scales.

If you’re living in the United States, you’re probably accustomed to reading temperatures in Fahrenheit. On a summer day with the sun beating down on you, it may feel like almost 100 degrees, while a winter day may feel closer to 40 degrees. Yet, if you were living in almost any other country in the world, you’re likely used to reading temperatures in Celsius. In this case, 40 degrees describes a hot summer day, while zero degrees would be more typical of a winter day.

The Fahrenheit scale was created by Daniel Gabriel Fahrenheit in 1724. He originally created the scale to measure temperature using mercury thermometers, which he also invented. The Celsius scale was created by Anders Celsius in 1742. But when the scale was first introduced, Celsius used the reverse of today’s scale. He labeled 0 as the boiling point of water and 100 as the freezing point. After Celsius’ death, Swedish taxonomist Carl Linnaeus flipped the Celsius scale into what it is today, making 100 represent boiling temperature and 0 as the freezing point.