Fahrenheit to Celsius, Celsius to Fahrenheit and kelvin
To change Fahrenheit to Celsius, subtract 32 and multiply by 5/9. To change Celsius to Fahrenheit, multiply by 9/5 and add 32. So 350 °F is about 176.7 °C and 20 °C is exactly 68 °F.
Inputs used by this calculator
Temperature Converter uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Temperature | 20 | Any finite number supported by the formula | Supplies the temperature quantity used by the published equation or result breakdown. |
| From | Celsius | Celsius · Fahrenheit · Kelvin | Selects the unit or conversion path used by Temperature Converter. |
| To | Fahrenheit | Celsius · Fahrenheit · Kelvin | Selects the unit or conversion path used by Temperature Converter. |
The two formulas
Water freezes at 32 °F and 0 °C and boils at 212 °F and 100 °C at sea level. The Fahrenheit scale puts 180 degrees between those points and Celsius puts 100, so one Celsius degree is 1.8 Fahrenheit degrees. That is why the formulas multiply by 9/5 or 5/9 and also shift by 32.
°C = (°F − 32) × 5/9°F = °C × 9/5 + 32K = °C + 273.15A quick estimate in your head
For weather, doubling the Celsius value and adding 30 gets close: 15 °C becomes about 60 °F against an exact 59 °F. Going the other way, subtract 30 from Fahrenheit and halve it. The shortcut drifts as temperatures move away from about 10 °C, so use the calculator for cooking, medicine or anything precise.
Oven temperatures
American recipes use Fahrenheit, and many recipes from elsewhere use Celsius rounded to the nearest 5 or 10 degrees. 350 °F is 176.7 °C and usually appears as 175 or 180 °C; 425 °F is 218.3 °C, often written 220 °C. Many recipes also suggest a lower setting for convection or fan ovens, so check the recipe's own note.
Body temperature readings
98.6 °F is the traditional reference for body temperature and converts to 37 °C. Readings vary from person to person, through the day and with the place the thermometer is used. For fever guidance, follow your clinician or the instructions that came with the thermometer rather than a single conversion.
Kelvin and absolute zero
Kelvin is the SI unit of temperature. It uses the same degree size as Celsius but starts at absolute zero, so 0 K is −273.15 °C and −459.67 °F. Kelvin is written without a degree sign: 293.15 K, not 293.15 °K. The calculator rejects any value colder than absolute zero.
Where the scales meet
At −40 the two scales read the same number, so −40 °F equals −40 °C. Above that point the Fahrenheit number is always larger. U.S. forecasts from the National Weather Service use Fahrenheit, while most other countries and science use Celsius.
Common temperatures in three scales
| Reference | Fahrenheit | Celsius | Kelvin |
|---|---|---|---|
| Absolute zero | -459.67 °F | -273.2 °C | 0 K |
| Fahrenheit and Celsius meet | -40 °F | -40 °C | 233.15 K |
| Home freezer | 0 °F | -17.8 °C | 255.37 K |
| Water freezes | 32 °F | 0 °C | 273.15 K |
| Refrigerator | 38 °F | 3.3 °C | 276.48 K |
| Room temperature | 68 °F | 20 °C | 293.15 K |
| Warm summer day | 86 °F | 30 °C | 303.15 K |
| Traditional body temperature | 98.6 °F | 37 °C | 310.15 K |
| Hot day | 100 °F | 37.8 °C | 310.93 K |
| Water boils (sea level) | 212 °F | 100 °C | 373.15 K |
| Oven: moderate | 350 °F | 176.7 °C | 449.82 K |
| Oven: hot | 425 °F | 218.3 °C | 491.48 K |
Frequently asked questions
What is 350 °F in Celsius?
176.7 °C. Recipes usually round it to 175 or 180 °C.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. For 68 °F: (68 − 32) × 5/9 = 20 °C.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For 25 °C: 25 × 1.8 + 32 = 77 °F.
What is 100 °F in Celsius?
About 37.8 °C.
When are Fahrenheit and Celsius equal?
At −40, where −40 °F and −40 °C are the same temperature.
Is 0 °C the same as 32 °F?
Yes. Both are the freezing point of water at standard pressure.
Why is kelvin written without a degree sign?
Kelvin is an absolute SI unit, so the value is written as a number of kelvins, such as 300 K.
What to keep in mind
Temperatures below absolute zero are rejected: −273.15 °C, −459.67 °F and 0 K describe the same lower boundary.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.