Temperature Converter: Celsius, Fahrenheit, Kelvin

A recipe in Celsius, a thermostat in Fahrenheit, a science problem in Kelvin — temperature scales are everywhere, and converting them in your head is easy to get wrong. This guide explains the exact formulas behind each scale, walks you through a worked example, and shows how to get an instant answer with the Temperature Converter. It is free, accurate, and runs entirely in your browser, so you can convert C to F, F to C or anything in between in a single tap.

How temperature conversion works

Three scales cover almost everything you will meet. Celsius (C) sets water's freezing point at 0 and boiling at 100. Fahrenheit (F) sets them at 32 and 212. Kelvin (K) starts at absolute zero, the coldest possible temperature, and uses the same step size as Celsius.

The core formulas are:

• Celsius to Fahrenheit: F = C times 9/5 + 32
• Fahrenheit to Celsius: C = (F minus 32) times 5/9
• Celsius to Kelvin: K = C + 273.15
• Kelvin to Celsius: C = K minus 273.15

The 9/5 factor reflects that one Celsius degree is 1.8 Fahrenheit degrees, and the +32 shifts the starting point.

How to use the Temperature Converter

Getting an answer takes seconds:

1. Open the Temperature Converter.
2. Type your value into the field — for example 37.
3. Pick the unit you are starting from (Celsius, Fahrenheit or Kelvin).
4. Read the converted result in all the other scales at once.
5. Change the number to instantly recalculate.

There is nothing to install and no sign-up. The conversion updates live as you type.

Worked example: 37 C to Fahrenheit

Say you want to convert normal body temperature, 37 C, to Fahrenheit.

Apply F = C times 9/5 + 32:

• 37 times 9/5 = 66.6
• 66.6 + 32 = 98.6

So 37 C equals 98.6 F — the familiar body-temperature reading. To go the other way, take 98.6 F: subtract 32 to get 66.6, then multiply by 5/9 to land back on 37 C. The converter does this rounding cleanly for you.

Quick reference table

Common temperatures across all three scales:

The last row is a typical oven baking temperature, handy when a recipe uses the other scale.

When you will need it

Temperature conversion shows up constantly: following an overseas recipe, checking a weather forecast while travelling, doing physics or chemistry homework that demands Kelvin, setting a thermostat installed in the wrong unit, or interpreting a fever reading from an imported thermometer. Anyone working across the metric and imperial worlds reaches for this regularly, and a quick converter beats memorising formulas every time.

Tips and common mistakes

A few things trip people up:

• Do not forget the +32 offset. Multiplying by 9/5 alone is the most common error.
• Kelvin uses 273.15, not 273, when you need precision.
• Negative Celsius values are fine — they convert normally — but you cannot go below 0 K, which is absolute zero.
• For a rough mental estimate of C to F, double the Celsius value and add 30. It is close enough for weather, though the tool is exact.

For other quick conversions, try the Unit Converter for length, weight and volume, or browse all the free calculators.

Is it private?

Yes. The Temperature Converter runs entirely in your browser using simple arithmetic. Nothing you type is uploaded to a server or stored, so it works offline once the page loads and keeps your inputs completely private. You can also explore the rest of the free tools the same way — no account, no tracking of your values.