Celsius to Fahrenheit Converter

Celsius to Fahrenheit — quick reference

The formula

Fahrenheit and Celsius are two linear scales with different zero points and step sizes, so the conversion is a multiply and an add — not a single factor:

°F = °C × 9/5 + 32

Worked example with the default: 20 × 9/5 + 32 = 36 + 32 = 68.0 °F.

The scales cross at −40, where −40 °C equals −40 °F — the one temperature that reads the same on both. Other anchors: 0 °C = 32 °F (water freezes) and 100 °C = 212 °F (water boils at sea level).

How to use the celsius to fahrenheit converter

Celsius reaches US readers through the weather app for a trip abroad, a hotel thermostat set in metric, or a recipe that gives the oven in degrees C. This converter turns Celsius into the Fahrenheit you read instinctively; Swap goes the other way when you need to enter Fahrenheit.

For weather, a handful of anchor points do most of the work. 0 °C is freezing (32 °F), 20 °C is a pleasant 68 °F, 30 °C is a warm 86 °F, and 37 °C — body temperature — is 98.6 °F. Slot the forecast between those and you’ll know whether to pack a jacket without doing the full arithmetic every time.

Cooking is where the exact number matters more. Metric recipes quote the oven in Celsius, and the conversions aren’t intuitive: a “moderate” 180 °C is 356 °F, and a hot 220 °C is 428 °F. Ovens are marked in 25-degree Fahrenheit steps, so convert and then round to the nearest mark — 356 °F means setting the dial to 350.

The mental shortcut is “double and add 30” — for 20 °C, 40 plus 30 is 70 °F, against the true 68. It’s close for everyday temperatures but drifts as you go up (at 200 °C it’s off by about 30 degrees), so use it for deciding what to wear and the exact formula for anything you’re cooking or setting a thermostat to.

Frequently asked questions