Temperature Converter

Instantly convert between Celsius (℃), Fahrenheit (℉), Kelvin (K), and Rankine (°R), and see the step-by-step conversion formulas.

Enter a value in any field and the other units will convert instantly.

Conversion Formulas

Reference Points

Click "Apply" to fill the temperature into the fields above.

Reference Point℃℉K°R

Kelvin (K) and Rankine (°R) are absolute temperature scales, starting from absolute zero, so they cannot be negative. Absolute zero is -273.15℃ = -459.67℉ = 0K = 0°R. Entering a temperature lower than this will display a warning.

What is the Temperature Converter?

Ever get stuck converting between Celsius and Fahrenheit for a weather forecast, a recipe, or a science project? This temperature converter instantly calculates between Celsius (℃), Fahrenheit (℉), Kelvin (K), and Rankine (°R). Just type a value in one field and all others update in real time. Unlike other converters, this tool also shows you the exact formulas and step-by-step calculations used for your specific numbers, making it perfect for students and professionals. You can also apply common reference points like 'Human Body Temperature' or 'Oven Baking Temperature' with a single click and adjust the decimal precision for your results.

How to use

  1. Enter a temperature into any of the four fields: 'Celsius ℃', 'Fahrenheit ℉', 'Kelvin K', or 'Rankine °R'.
  2. All other fields update automatically as you type, showing the converted values.
  3. Below the inputs, review the 'Conversion Formulas' section to see the exact calculations for your entry.
  4. To use a preset, scroll to the 'Reference Points' table and click 'Apply' on an entry like 'Water Boiling Point'.
  5. Use the 'Decimal Places' dropdown to control the rounding of the results, from an integer to no rounding at all.
  6. Click 'Clear' to reset all fields, or 'Example' to see a sample conversion for human body temperature.

Frequently asked questions

What is Kelvin (K) used for?

Kelvin is the standard for scientific temperature measurement. Its scale starts at absolute zero (0K), the coldest possible temperature, which simplifies calculations in physics and chemistry. The size of a kelvin is the same as a degree Celsius.

What is the Rankine (°R) scale?

Rankine is an absolute temperature scale that uses Fahrenheit degrees. Just as Kelvin is the absolute version of Celsius (starting at 0), Rankine is the absolute version of Fahrenheit. It is sometimes used in specific engineering fields in the US.

Why does the tool show the conversion formulas?

Displaying the formulas provides transparency and helps with learning. It allows students to understand the conversion process and lets professionals easily verify and cite the calculations for reports or documentation.

I see a warning about a temperature being 'below absolute zero'. What does that mean?

Absolute zero (0K or -273.15°C) is the lowest physically possible temperature. The tool warns you if you enter a value below this because it's a theoretical impossibility. By definition, the Kelvin and Rankine scales cannot be negative.

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