Temperature Converter

Type a temperature in Celsius, Fahrenheit or Kelvin and see it on the other scales immediately. The converter shows the formula it uses, so you can check the arithmetic or do it by hand next time.

Use it for weather forecasts when travelling, oven settings in foreign recipes, body temperature readings, science homework and lab work. Negative temperatures are supported, down to absolute zero.

How to use the Temperature Converter tool

1. Type the number you want to convert in the Value box, for example 25 with Celsius selected.
2. Pick the unit you have in From and the unit you need in To.
3. Read the result instantly in large type, with the exact formula used shown underneath.
4. Open All temperature units to see the same value in every unit at once, or press ⇄ to swap the direction.
5. Use Copy result to paste the converted number into a document, spreadsheet or message.

Why use ToolOrca Temperature Converter

• Celsius, Fahrenheit and Kelvin
• Correct offset formulas, not just a factor
• Negative and below-zero values
• Formula shown for every direction
• All three scales in one table
• Instant, free and offline

Temperature conversion formulas

Unlike most units, temperature scales have different zero points, so converting needs an offset as well as a factor. The Fahrenheit scale puts the freezing point of water at 32 °F and boiling at 212 °F, a span of 180 degrees, while Celsius uses 0 °C and 100 °C. That gives the factor 180/100 = 9/5.

°F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9. Kelvin uses Celsius-sized degrees starting at absolute zero: K = °C + 273.15.

Worked example: 25 °C × 9/5 = 45, and 45 + 32 = 77 °F. Going back, (77 − 32) × 5/9 = 25 °C.

Useful reference temperatures

Water freezes at 0 °C (32 °F, 273.15 K) and boils at 100 °C (212 °F) at sea level. Normal body temperature is about 37 °C (98.6 °F). A comfortable room is 20–22 °C (68–72 °F). −40 is the one temperature that reads the same in Celsius and Fahrenheit.