Celsius to Fahrenheit Converter
Convert temperatures from Celsius to Fahrenheit, with Kelvin and Rankine alongside. Type a temperature in °C and get °F instantly, or swap the units to go from Fahrenheit to Celsius. It shows the formula so you can check it by hand.
Celsius to Fahrenheit converter
How to use the celsius to fahrenheit converter
- Enter the degrees Celsius. Type the number of degrees Celsius you want to convert. Decimals work, and so do fractions entered as decimals.
- Check the units. The converter starts as degrees Celsius to degrees Fahrenheit. Use the From and To menus to change either unit, or press Swap to reverse them.
- Read the result. The answer appears at the top, with the conversion factor and the same value in other common units underneath.
- Copy or print. Copy the result to paste into a message, or print a clean summary to keep with your plans.
How to convert degrees Celsius to degrees Fahrenheit
°F = °C × 9/5 + 32
°C = (°F − 32) × 5/9
K = °C + 273.15
The two scales have different zero points and different degree sizes: a Celsius degree is 1.8 times a Fahrenheit degree, and 0 °C is 32 °F. So you multiply by 1.8 and add 32, not just multiply. The scales meet at −40, where −40 °C equals −40 °F.
Worked examples
Water. Freezing is 0 °C = 32 °F and boiling at sea level is 100 °C = 212 °F.
Weather. 25 °C is 77 °F, a warm day, while 30 °C is 86 °F and 35 °C is 95 °F.
An oven. 180 °C is 356 °F, 200 °C is 392 °F and 220 °C is 428 °F, usually written as 350, 400 and 425 °F on recipes.
Body temperature. 37 °C is 98.6 °F, the traditional average, and 38 °C is 100.4 °F.
Celsius to Fahrenheit chart
| Celsius | Fahrenheit | Kelvin |
|---|---|---|
| -40 °C | -40 °F | 233.15 K |
| -20 °C | -4 °F | 253.15 K |
| -10 °C | 14 °F | 263.15 K |
| 0 °C | 32 °F | 273.15 K |
| 5 °C | 41 °F | 278.15 K |
| 10 °C | 50 °F | 283.15 K |
| 15 °C | 59 °F | 288.15 K |
| 20 °C | 68 °F | 293.15 K |
| 25 °C | 77 °F | 298.15 K |
| 30 °C | 86 °F | 303.15 K |
| 37 °C | 98.6 °F | 310.15 K |
| 40 °C | 104 °F | 313.15 K |
| 100 °C | 212 °F | 373.15 K |
| 180 °C | 356 °F | 453.15 K |
| 200 °C | 392 °F | 473.15 K |
| 220 °C | 428 °F | 493.15 K |
A quick mental trick
For a rough estimate, double the Celsius value and add 30. It is close at everyday temperatures (20 °C gives 70 °F against an exact 68 °F) but drifts when it is very hot or cold. For cooking and science, use the exact formula. Cooking temperatures are often rounded in recipes: 180 °C is 356 °F exactly, but recipes say 350 °F, and fan ovens run about 20 °C cooler than conventional ones. Absolute zero is 0 K, −273.15 °C or −459.67 °F, so the calculator rejects anything lower.
Features
- Convert degrees Celsius to degrees Fahrenheit and back, with a Swap button.
- Other common units shown at once, so you rarely need a second conversion.
- Exact definitions from NIST, with 8 significant digits.
- Copy result, reset and a printable report in five themes on A4 or Letter.
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Frequently asked questions
How do you convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8), then add 32. For 20 °C, 20 × 1.8 + 32 = 68 °F.
How do you convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. For 98.6 °F, (98.6 − 32) × 5/9 = 37 °C.
What temperature are Celsius and Fahrenheit equal?
At −40. Both scales read −40 at that temperature, so −40 °C is −40 °F.
What is 180 °C in Fahrenheit?
180 °C is 356 °F, though recipes usually give 350 °F for gas mark 4.
What is the easy way to estimate °F from °C?
Double the Celsius and add 30. It is rough: 25 °C gives 80 °F against an exact 77 °F.
How many kelvins is 0 °C?
Zero degrees Celsius is 273.15 K. A kelvin is the same size as a degree Celsius, so you only add 273.15.
What is absolute zero in Fahrenheit?
Absolute zero is −273.15 °C, which is −459.67 °F, or 0 K and 0 °R.
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Sources and references
About this calculator
Written and maintained by Rashid Mehmood, founder of CalcTen. The formulas are unit-tested against hand-worked examples, and the content is reviewed whenever product sizes or guidance change. Last updated 14 November 2026. See our editorial policy.
Conversion factors come from NIST and other standards bodies, and results are rounded for display. For safety-critical work such as medicines, engineering or navigation, verify with an authoritative source. Read the disclaimer.