Celsius to Fahrenheit

The exact conversion

Celsius to Fahrenheit is the weather and kitchen conversion for anyone reading a US forecast or a US oven dial. The scales do not share a zero, so you cannot multiply by a single factor. The definition is °F = °C × 9/5 + 32, which is the same as multiplying by 1.8 and then adding 32. Zero degrees Celsius, the freezing point of water, is 32 °F. One hundred degrees Celsius, boiling at ordinary pressure, is 212 °F. The gap between those two points is 100 Celsius degrees and 180 Fahrenheit degrees.

The formula used above is °F = °C × 9/5 + 32. Both boxes stay in step, so you can start from either unit. Results are rounded for display; the factor itself is the legal definition, not a rounded shortcut.

Worked examples

Each line is the same formula with a new starting number. You can match it against the converter by typing the value on the left.

• 0 °C: 0 × 9/5 + 32 = 32 °F.
• 20 °C: 20 × 9/5 + 32 = 68 °F.
• 180 °C: 180 × 9/5 + 32 = 356 °F.

Where the rounding matters

A room at 20 °C is 68 °F. A warm day at 30 °C is 86 °F. Normal body temperature, 37 °C, is 98.6 °F. An oven at 180 °C is 356 °F, and 200 °C is 392 °F. The two scales meet at −40: −40 °C is −40 °F, which is a useful check if a result looks impossible. A shortcut for weather is to double the Celsius figure and add 30. For 20 °C that gives 70 °F, two degrees above the real 68 °F. Use the full formula for an oven or a fever.

Adding 32 without scaling is the usual mistake, and it is far off: 20 + 32 = 52, not 68. The 9/5 has to happen first. You can also go the other way on this page by typing in the Fahrenheit box. The dedicated Fahrenheit to Celsius page explains that direction with its own examples.

Conversion table: celsius to fahrenheit