Free Celsius to Fahrenheit Converter

What is a degree Celsius? What is a degree Fahrenheit?

The degree Celsius (°C) is the everyday temperature unit across Europe and almost everywhere else in the world. It was set out by the Swedish astronomer Anders Celsius in 1742, and it is built around water: 0 °C is the freezing point of water and 100 °C is its boiling point at standard atmospheric pressure. That round 100-degree span is what makes Celsius easy to picture — 20 °C is a comfortable room, 30 °C is a hot day, and anything below 0 °C means ice. Today the scale is formally defined through the kelvin: 0 °C equals exactly 273.15 K.

The degree Fahrenheit (°F) is the everyday temperature unit in the United States. Daniel Gabriel Fahrenheit set it out in the early 1700s, and on his scale water freezes at 32 °F and boils at 212 °F — a 180-degree span for the same change that Celsius covers in 100 degrees. That means one Celsius degree is a bigger step than one Fahrenheit degree: 1 °C equals a step of 1.8 °F. A Fahrenheit degree is finer-grained, which is why US weather forecasts can say 72 °F where a European forecast says 22 °C and both mean the same pleasant afternoon.

Because the two scales start at different zero points, converting is not just a multiplication: you must also shift by 32. That shift is the only reason the formula has a plus 32 in it, and it is also why minus 40 is the same number on both scales.

How to use

1. Type a temperature in Celsius in the left box — the Fahrenheit value appears instantly on the right, with no button to press.
2. Or type in the Fahrenheit box instead: both boxes are editable, and typing in either one updates the other at once.
3. Press Swap to flip the direction. The converted value carries over as the new starting number, so you can keep converting back and forth.
4. Negative numbers work normally — type -10 for a freezing day and you will get 14 °F. The reference table below covers freezing, body temperature, boiling, and oven settings.

Celsius to Fahrenheit formula

To go from Celsius to Fahrenheit, scale up by 9/5 and then shift by 32:

°F = (°C × 9 ÷ 5) + 32

And the reverse direction undoes both steps, in the opposite order:

°C = (°F − 32) × 5 ÷ 9

• °C — temperature in degrees Celsius
• °F — temperature in degrees Fahrenheit
• 9 ÷ 5 (1.8) — the ratio of the size of one Celsius degree to one Fahrenheit degree
• 32 — the offset: water freezes at 0 °C but at 32 °F

A quick mental check: double the Celsius figure, subtract 10 percent, then add 32. For 20 °C that gives 40, minus 4, plus 32 — exactly 68 °F. If you need other units in one place, the general unit converter covers more units than any single page here.

Worked example

Celsius to Fahrenheit conversion table

Every value is computed from the exact formula °F = (°C × 9 ÷ 5) + 32. Note how minus 40 is the same on both scales.

Reference points: weather, oven, and body

These are the numbers worth memorising, so a forecast or a recipe in either scale makes sense at a glance:

• Weather — below 0 °C (32 °F) is freezing; 0–10 °C (32–50 °F) is cold; 10–20 °C (50–68 °F) runs cool to mild; 20–25 °C (68–77 °F) is comfortable; 25–30 °C (77–86 °F) is warm; above 30 °C (86 °F) is hot.
• Oven settings — a slow oven at 160 °C is 320 °F; a moderate oven at 180 °C is 356 °F; a hot oven at 200 °C is 392 °F; a very hot oven at 220 °C is 428 °F.
• Fridge and freezer — a fridge should sit near 4 °C (39.2 °F); a freezer near −18 °C (−0.4 °F).
• Body temperature — normal is 37 °C (98.6 °F); 38 °C (100.4 °F) is generally treated as a fever.
• Hot water — a comfortable bath is about 37–40 °C (98.6–104 °F); water above 60 °C (140 °F) scalds quickly.

For the background on why Europe and the US ended up with different systems, read the metric vs imperial conversion guide for Europe.

Frequently asked questions

How do I convert Celsius to Fahrenheit?

Multiply the Celsius temperature by 9, divide by 5, then add 32. For example, 20 degrees Celsius times 9 divided by 5 is 36, plus 32 gives 68 degrees Fahrenheit.

What is 20 degrees Celsius in Fahrenheit?

20 degrees Celsius is 68 degrees Fahrenheit. Twenty degrees is a comfortable room temperature, and 68 Fahrenheit is the matching setting on a US thermostat.

What is 0 degrees Celsius in Fahrenheit?

0 degrees Celsius is 32 degrees Fahrenheit. Zero Celsius is the freezing point of water, and 32 Fahrenheit is the same point on the Fahrenheit scale.

What is 37 degrees Celsius in Fahrenheit?

37 degrees Celsius is 98.6 degrees Fahrenheit, the usual figure quoted for normal human body temperature. A reading of 38 degrees Celsius, or 100.4 Fahrenheit, is generally treated as a fever.

What is 100 degrees Celsius in Fahrenheit?

100 degrees Celsius is 212 degrees Fahrenheit, the boiling point of water at sea level. Both scales agree that water boils at this temperature, they just number it differently.

Can Celsius temperatures be negative?

Yes. Negative Celsius values are normal winter temperatures in much of Europe and North America: minus 10 Celsius is 14 Fahrenheit, and minus 40 is the point where both scales read the same number.

What Celsius temperature is 350 degrees Fahrenheit for baking?

350 degrees Fahrenheit is about 177 degrees Celsius, usually rounded to 180 degrees in European recipes. Many cooks set a fan oven about 20 degrees lower than a conventional oven, so 160 degrees fan is a common equivalent.

Why does the US use Fahrenheit?

The Fahrenheit scale was set out by Daniel Gabriel Fahrenheit in the early 1700s and stayed in everyday use in the United States, while most of the world moved to Celsius. Weather, cooking, and body temperature in the US are still given in Fahrenheit, which is why this converter is useful when reading American sources.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units (SI), including Celsius and Fahrenheit definitions.
• BIPM SI Brochure — The International System of Units, including the kelvin definition behind the Celsius scale (0 °C = 273.15 K).
• International Temperature Scale of 1990 (ITS-90) — the practical scale used to realise temperature measurements.

Disclaimer: Temperature conversions are exact arithmetic; oven dials and thermometers vary, so trust the thermometer, not the dial, for food safety.

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