Celsius to Fahrenheit Converter

How to convert Celsius to Fahrenheit

°F = °C × 1.8 + 32        (equivalently: °C × 9/5 + 32)

The 1.8 and the 32 both come from how the scales were built. Water freezes at 0 °C and 32 °F, and boils at 100 °C and 212 °F at sea level — so 100 Celsius degrees span 180 Fahrenheit degrees, which is 1.8 °F per °C, and the freezing points sit 32 °F apart. That makes the conversion a definition, not an approximation.

Worked example, 20 °C: 20 × 1.8 = 36, + 32 = 68 °F — room temperature, and the default value on this page.

The mental shortcut, and where it breaks

Everyone learns °F ≈ °C × 2 + 30, and for weather it's good enough: at 10 °C it lands exactly on 50 °F, and at 20 °C it gives 70 °F against the true 68 °F — two degrees off, which tells you the same thing about whether to take a jacket.

It drifts as you leave that range. At 30 °C you're 4 °F high, at body temperature 5.4 °F high, and at boiling it gives 230 °F against 212 °F — 18 °F of error, which is the difference between a simmer and a hard boil. Use it for weather; use the exact formula for ovens, fevers, and anything with a threshold.

How to use this converter

1. Type the temperature in Celsius (20 °C is filled in, so the page shows a result immediately).
2. Read the Fahrenheit line — the whole-degree value is what a thermostat or recipe wants.
3. Check the shortcut line to see how far the mental math would have been off.
4. Open the chart for the temperatures people actually look up: freezing, room, body, oven.

Frequently asked questions

What is 0 °C in Fahrenheit?

32 °F — the temperature water freezes at.

What is 37 °C in Fahrenheit?

98.6 °F, normal body temperature. Round to 99 °F if you're reading a thermometer that only shows whole degrees.

Is 30 °C hot?

86 °F — hot by any standard, and hot enough that the mental shortcut starts lying to you (it says 90 °F).

How do I convert Fahrenheit back to Celsius?

Subtract 32, then divide by 1.8: (68 − 32) ÷ 1.8 = 20 °C. Same arithmetic run backwards.

At what temperature are Celsius and Fahrenheit equal?

−40 degrees. It's the one point where the two scales cross, and a useful check: if a conversion ever gives you the same number at a different temperature, something's wrong.

Data sources: The conversion is a definition, not an approximation — both scales are fixed by the freezing and boiling points of water, and that boiling point falls with altitude, so high-elevation cooking times differ even when the number on the dial is right. Every figure on this page was produced by the converter using °F = °C × 1.8 + 32 and can be reproduced by entering the same Celsius value. Related tools: inches to cm converter, percentage calculator, all math calculators.