Celsius to Fahrenheit Converter
Type a temperature in Celsius to get Fahrenheit. 25 °C, a warm day, is 77 °F.
25 °C =
77°F
25 degrees Celsius is 77 degrees Fahrenheit.
- In kelvin
- 298.15 K
How this works: Method, 4 sources, Checked against 2 worked examples,
How this works
Method
Multiply the Celsius temperature by 9/5 (that is, 1.8), then add 32. The two steps are needed because the scales differ in two ways: a Fahrenheit degree is smaller (180 of them span freezing to boiling, against 100 Celsius degrees), and the Fahrenheit scale starts its count 32 degrees below the freezing point of water. Full method
Sources
How it’s tested
2 worked examples for this page are checked by automated tests before every release: given the inputs, the tool must show the expected answer.
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Changes
- Ask understands “5 ft 9 in to cm” and “2 cups of flour in grams” and answers at once, and a decimal comma (“2,5”) reads as 2.5.
- First published: 89 everyday units across ten quantities, with 58 pages for common pairs such as cm to inches and Celsius to Fahrenheit.
How to convert Celsius to Fahrenheit
Multiply the Celsius temperature by 9/5 (that is, 1.8), then add 32. The two steps are needed because the scales differ in two ways: a Fahrenheit degree is smaller (180 of them span freezing to boiling, against 100 Celsius degrees), and the Fahrenheit scale starts its count 32 degrees below the freezing point of water.
For a mild 18 °C spring day: 18 × 1.8 = 32.4, and 32.4 + 32 = 64.4 °F. For a moderate oven at 180 °C: 180 × 1.8 = 324, plus 32 gives 356 °F, which recipes round to 350 °F.
The order matters. Adding 32 first and then multiplying is wrong for every temperature: 18 °C would come out as (18 + 32) × 1.8 = 90 °F instead of 64.4. The mistake always lands 25.6 degrees too high.
°F = °C × 9/5 + 32
- NIST gives the relation as t/°F = 1.8 × t/°C + 32, so water freezes at 32 °F and boils at 212 °F at standard atmospheric pressure. Source: NIST, SI units: temperature.
How to estimate Celsius to Fahrenheit in your head
Double the Celsius figure and add 30. For 18 °C: 36 + 30 = 66 °F, against an exact 64.4. The shortcut is spot on at 10 °C (50 °F) and drifts as you move away: about 2 degrees high at 20 °C and 4 degrees high at 30 °C, so it works best for weather.
For cooking temperatures the error grows too large (180 °C would come out as 390 °F instead of 356), so use the real formula or the chart for ovens.
Celsius to Fahrenheit chart
Weather, household and kitchen temperatures. Oven settings are the exact conversions; dials are usually marked in rounder numbers.
| Degrees Celsius (°C) | Degrees Fahrenheit (°F) | Example |
|---|---|---|
| -40 | -40 | both scales agree |
| -18 | -0.4 | home freezer |
| -10 | 14 | |
| 0 | 32 | water freezes |
| 4 | 39.2 | fridge |
| 10 | 50 | |
| 15 | 59 | |
| 20 | 68 | cool room |
| 22 | 71.6 | |
| 25 | 77 |
Show all 21 rowsShow fewer
| 30 | 86 | |
| 35 | 95 | |
| 37 | 98.6 | traditional body temperature |
| 40 | 104 | |
| 60 | 140 | |
| 100 | 212 | water boils (sea level) |
| 160 | 320 | |
| 180 | 356 | moderate oven |
| 200 | 392 | |
| 220 | 428 | hot oven |
| 250 | 482 |
Frequently Asked Questions
What is 25 °C in Fahrenheit?
25 °C is 77 °F: 25 × 1.8 = 45, plus 32. It is a typical comfortable summer afternoon.
Is 37 °C exactly 98.6 °F?
Yes, the arithmetic is exact: 37 × 1.8 + 32 = 98.6. 37 °C / 98.6 °F is the traditional reference value for body temperature; real readings vary from person to person and through the day.
At what temperature are Celsius and Fahrenheit equal?
At −40. Plug −40 into the formula: −40 × 1.8 = −72, and −72 + 32 = −40. It is the only crossing point.