Temperature Converter
Convert celsius to fahrenheit, fahrenheit to celsius and kelvin in either direction. The answer updates as you type, negative values included. It runs in your browser with nothing to install and no sign up.
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Quick answer
To convert celsius to fahrenheit, multiply by 1.8 and add 32. So 20 degrees celsius is 68 fahrenheit. Type your figure above and the answer appears immediately, and the same tool handles fahrenheit to celsius and kelvin in either direction.
Converting temperature in three steps
Enter the temperature
Type into the left box. Negative numbers work exactly as you would expect.
Pick the two scales
Celsius and Fahrenheit are preset. Switch either dropdown for Kelvin.
Read or swap
The answer is on the right. Press the swap arrows to reverse the direction.
°F = (°C × 1.8) + 32Reverse it with °C = (°F − 32) ÷ 1.8. Kelvin is °C + 273.15.
celsius to fahrenheit needs a multiply and an add
Unlike length or weight, temperature scales do not share a zero point. Water freezes at 0 celsius but 32 fahrenheit, which is why converting celsius to fahrenheit needs both a multiplication by 1.8 and an addition of 32. Skip the addition and every answer will be 32 degrees too low. That single quirk is the reason people reach for a converter rather than doing it in their head.
fahrenheit to celsius, subtract before you divide
Going from fahrenheit to celsius the order flips: subtract 32 first, then divide by 1.8. Doing it the other way round gives a wrong answer, which is the most common mistake with this pair. A useful anchor is that the two scales cross at minus 40, where both read the same number. Body temperature is another one worth memorising: 37 celsius is 98.6 fahrenheit.
kelvin to celsius is a straight subtraction
Kelvin uses the same degree size as celsius but starts at absolute zero, so kelvin to celsius is simply a subtraction of 273.15. There are no negative kelvin values, and the scale is written without a degree symbol. It turns up in physics, chemistry and lighting, where a bulb described as 4000K is telling you its colour temperature rather than how hot it gets.
celsius to kelvin for lab and lighting work
Converting celsius to kelvin means adding 273.15, so room temperature at 20 celsius is 293.15 K. Because the degree size is identical, a change of one celsius is a change of one kelvin, which makes the two interchangeable when you are talking about differences rather than absolute readings.
Common temperature conversions
| Celsius | Fahrenheit | Kelvin |
|---|---|---|
| -40 °C | -40 °F | 233.15 K |
| 0 °C | 32 °F | 273.15 K |
| 10 °C | 50 °F | 283.15 K |
| 20 °C | 68 °F | 293.15 K |
| 25 °C | 77 °F | 298.15 K |
| 37 °C | 98.6 °F | 310.15 K |
| 100 °C | 212 °F | 373.15 K |
| 180 °C | 356 °F | 453.15 K |
| 200 °C | 392 °F | 473.15 K |
Why choose our temperature converter
Free and unlimited
No account, no sign up, no daily cap.
Runs in your browser
Nothing is sent to a server, so it works offline once loaded.
Every unit in one place
Swap either side and the whole category is in the dropdowns.
Instant on mobile
Results update as you type, with no page reload.
Temperature questions
What is the quickest mental estimate?+
At what point do the two scales meet?+
Does kelvin use a degree symbol?+
What oven temperature is 350 F?+
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