Celsius to Fahrenheit Converter
Convert °C to °F instantly — type in either box and the answer appears as you type.
40°C = 104°F
The formula
°F = °C × 9/5 + 32
Example: 40°C converts to 104°F — 40 × 9/5 = 72, 72 + 32 = 104°F.
Celsius to Fahrenheit conversion table
How do you convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 and add 32: °F = °C × 9/5 + 32. For example, 40°C × 9/5 + 32 = 104°F.
What is the fastest way to estimate Celsius to Fahrenheit?
Double the Celsius number and add 30. For 20°C that gives roughly 70°F (the exact answer is 68°F) — handy for weather temperatures.
What is normal body temperature, 37°C, in Fahrenheit?
37°C equals 98.6°F — the classic value for normal human body temperature.
Why does the United States use Fahrenheit?
Fahrenheit was adopted in the 18th century when it was the standard scale in English-speaking countries. Most of the world switched to Celsius in the 1960s–70s, but the US kept Fahrenheit for everyday weather, cooking, and body temperature.