Different temperature scales are used for different purposes. Celsius and Fahrenheit are commonly used in everyday measurements, while Kelvin and Rankine are used in scientific and engineering contexts. Réaumur is an older scale still referenced in some historical or academic material.

This calculator makes it easy to move between these scales without manual calculation.

Celsius (°C): The standard metric temperature scale used by most of the world. It is based on the freezing point of water (0°C) and the boiling point of water (100°C).

Fahrenheit (°F): The standard scale used primarily in the United States and a few other territories. In this system, water freezes at 32°F and boils at 212°F.

Kelvin (K): A scientific scale used heavily in physics and engineering. It begins at “absolute zero” (0 K), which is the theoretical lowest possible temperature where all molecular movement stops. It does not use degrees.

Rankine (°R) & Réaumur (°Re): Older, specialized scales. Rankine is sometimes used in aerospace engineering, while Réaumur is a historical European scale still occasionally referenced in artisan cheese and syrup manufacturing.

Example 1: Holiday Planning & Weather (Fahrenheit to Celsius)

If you are traveling from the UK to the United States, you will notice weather forecasts use Fahrenheit. If a local forecast predicts a summer high of 90°F, inputting this into the calculator reveals it is roughly 32.2°C.

This quickly helps you understand that you need to pack for a very hot day rather than a mild one.

Example 2: Following Foreign Recipes (Fahrenheit to Celsius)

Many American baking blogs list oven temperatures in Fahrenheit. If a recipe asks you to bake a cake at 350°F. The calculator will show this converts to 176.6°C (which you would typically round to 180°C or 160°C for a fan-assisted UK oven).

If you need to convert recipe volumes, check out our Cooking Conversion Calculator.