Celsius to Fahrenheit Converter
To convert Celsius to Fahrenheit, multiply by 9/5 and add 32. 24 °C = 75.2 °F.
Sources: NIST SP 811, BIPM SI Brochure Updated
Result
20 °C = 68 °F
How to convert Celsius to Fahrenheit
°F = (°C × 9/5) + 32
The numbers in the formula are exact. Both scales are defined through the kelvin: a Celsius temperature is the kelvin temperature minus 273.15, and a Fahrenheit degree is 5/9 of a Celsius degree with 32 °F at 0 °C.
Worked example: 24 °C
- Start with the temperature in Celsius: 24 °C.
- Multiply by 9/5 (or 1.8): 24 × 9/5 = 43.2.
- Add 32: 43.2 + 32 = 75.2 °F.
Celsius and Fahrenheit side by side
Celsius to Fahrenheit chart
Degrees Celsius from −40 to 260 converted to degrees Fahrenheit with the exact formula, shown to five significant digits.
| °C | °F |
|---|---|
| −40 | −40 |
| −35 | −31 |
| −30 | −22 |
| −25 | −13 |
| −20 | −4 |
| −15 | 5 |
| −10 | 14 |
| −5 | 23 |
| 0 | 32 |
| 5 | 41 |
| 10 | 50 |
| 15 | 59 |
| 20 | 68 |
| 25 | 77 |
| 30 | 86 |
| 35 | 95 |
| 40 | 104 |
| 45 | 113 |
| 50 | 122 |
| 60 | 140 |
| °C | °F |
|---|---|
| 70 | 158 |
| 80 | 176 |
| 90 | 194 |
| 100 | 212 |
| 110 | 230 |
| 120 | 248 |
| 130 | 266 |
| 140 | 284 |
| 150 | 302 |
| 160 | 320 |
| 170 | 338 |
| 180 | 356 |
| 190 | 374 |
| 200 | 392 |
| 210 | 410 |
| 220 | 428 |
| 230 | 446 |
| 240 | 464 |
| 250 | 482 |
| 260 | 500 |
°F = (°C × 9/5) + 32. Factors: NIST SP 811, BIPM SI Brochure. unitcheck.net/temperature/celsius-to-fahrenheit/
Common values
| Celsius | Fahrenheit | What it is |
|---|---|---|
| −273.15 °C | −459.67 °F | absolute zero |
| −40 °C | −40 °F | the only temperature where both scales read the same |
| −18 °C | −0.4 °F | |
| 0 °C | 32 °F | freezing point of water |
| 20 °C | 68 °F | |
| 37 °C | 98.6 °F | conventional figure for normal body temperature |
| 100 °C | 212 °F | boiling point of water at standard pressure, to the nearest degree |
| 180 °C | 356 °F | |
| 200 °C | 392 °F | |
| 220 °C | 428 °F |
Why “double it and add 30” drifts
The shortcut replaces 9/5 with 2 and 32 with 30. At 10 °C it is exactly right (50 °F). At 20 °C it gives 70 °F instead of 68 °F, at 30 °C it gives 90 °F instead of 86 °F, and at an oven setting of 180 °C it gives 390 °F instead of 356 °F. Use it for the weather, not for cooking.
Going the other way? Use the Fahrenheit to Celsius converter.
Frequently asked questions
What is the formula for Celsius to Fahrenheit?
°F = (°C × 9/5) + 32. In words: multiply by 9/5 and add 32. Example: 24 °C = 75.2 °F.
At what temperature are Celsius and Fahrenheit equal?
At −40. Put −40 into either formula and the same number comes out: −40 °C = −40 °F. Above that point the Fahrenheit number is always the larger one.
What is 180 °C in Fahrenheit for an oven?
180 °C is exactly 356 °F; the nearest common Fahrenheit oven setting is 350 °F. Likewise 200 °C is 392 °F (nearest setting 400 °F) and 220 °C is 428 °F (425 °F). The chart on this page covers oven temperatures up to 260 °C.
Is there a quick way to estimate it?
Double the Celsius number and add 30. It is exact at 10 °C and within about 2 °F between 0 and 20 °C, but the error grows as you move away: at 100 °C it says 230 °F instead of 212 °F.
Is the conversion exact?
Yes. The factor 9/5 and the offset 32 are exact by definition, so the only rounding is in the number of decimals you display.
Sources
- NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B.8: Factors for Units Listed Alphabetically — exact factors are printed in bold in the NIST table (checked October 12, 2026)
- BIPM, The International System of Units (SI Brochure), 9th edition — defines the SI units, the prefixes and the units accepted for use with the SI