How to use the Temperature Converter
- Type the temperature you want to convert. Negative numbers are allowed.
- Choose the scale it is in now.
- Choose the scale you want.
- Read the result and use the reference table for common temperatures.
Formula used
°F = °C × 9 ÷ 5 + 32. °C = (°F − 32) × 5 ÷ 9. K = °C + 273.15.
Worked example
Here is the Temperature Converter worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Temperature | 37 |
| From | Celsius (°C) |
| To | Fahrenheit (°F) |
| Result | |
| Converted temperature | 98.6 |
| Formula used | C to F via Celsius |
Quick reference table
Common values converted with the units selected above.
| From | To |
|---|---|
| -40 C | -40 F |
| 0 C | 32 F |
| 25 C | 77 F |
| 37 C | 98.6 F |
| 100 C | 212 F |
The conversion formulas
To convert Celsius to Fahrenheit, multiply by 9, divide by 5 and add 32. To convert Fahrenheit to Celsius, subtract 32, multiply by 5 and divide by 9. To convert Celsius to Kelvin, add 273.15. For example, normal body temperature of 37°C is 37 × 9 ÷ 5 + 32 = 98.6°F.
The two scales meet at −40, where −40°C equals −40°F. Water freezes at 0°C, which is 32°F or 273.15 K, and boils at 100°C at sea level, which is 212°F or 373.15 K.
Temperatures worth remembering
A comfortable room is around 25°C, or 77°F. A fever is usually considered to begin at about 38°C, or 100.4°F, although the exact threshold depends on how the temperature is measured. A hot Indian summer day of 45°C is 113°F.
A typical oven setting of 180°C is 356°F, and 200°C is 392°F. If a recipe from abroad says 350°F, that is about 177°C, so most Indian ovens would be set to around 180°C.
The Kelvin scale
Kelvin is the scale used in physics and chemistry. It starts at absolute zero, the lowest temperature possible, which is −273.15°C. Because of that, Kelvin values are never negative, and the size of one kelvin equals the size of one degree Celsius.
The calculator rejects values below absolute zero, since no object can be that cold.
Mental shortcuts
For a quick Celsius to Fahrenheit estimate, double the number and add 30. For 20°C that gives 70°F, close to the exact 68°F. For Fahrenheit to Celsius, subtract 30 and halve it, so 70°F gives about 20°C. These shortcuts are fine for weather but not for cooking or science.
Use the calculator when accuracy matters, for example for lab work, medicine or food safety.
Reference points worth remembering
Water freezes at 0 °C (32 °F, 273.15 K) and boils at 100 °C (212 °F, 373.15 K) at sea-level pressure. Normal body temperature is about 37 °C (98.6 °F), and a comfortable room is around 20 to 22 °C (68 to 72 °F). The two scales meet at −40, where −40 °C equals −40 °F.
A quick mental shortcut to convert Celsius to Fahrenheit is to double the number and add 30; 20 °C gives about 70 °F, close to the exact 68 °F. Kelvin is used in science and has no negative values: 0 K is absolute zero, equal to −273.15 °C. Do not use these conversions for temperature differences, where 1 °C of change is 1.8 °F of change.
Frequently asked questions
What is 37°C in Fahrenheit?
37°C is 98.6°F, the traditional figure for normal body temperature.
How do I convert Fahrenheit to Celsius?
Subtract 32, multiply by 5 and divide by 9. For 98.6°F, that is 66.6 × 5 ÷ 9 = 37°C.
At what temperature are Celsius and Fahrenheit equal?
At −40. Both scales show the same number there.
What is 0°C in Kelvin?
0°C is 273.15 K.
What is absolute zero?
Absolute zero is 0 K, which is −273.15°C or −459.67°F. It is the lowest possible temperature.
Why does the calculator reject some values?
Any value below absolute zero is not physically possible, so the calculator shows an error instead of a result.
At what temperature are Celsius and Fahrenheit equal?
At −40, where −40 °C equals −40 °F.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.