Free Celsius Converter
Quick Reference
°F = °C × 9/5 + 32K = °C + 273.15
°R = (°C + 273.15) × 9/5
°Ré = °C × 4/5
0°C = 32°F = 273.15 K
0°C = 491.67°R = 0°Ré
Enter a value for instant conversion
The Celsius Converter is a free online temperature conversion calculator that lets you instantly convert temperatures from Celsius to Fahrenheit, Celsius to Kelvin, and any other common scale—as well as perform the reverse conversion. It serves as a versatile online thermometer converter for everyday use.
What Is the Celsius Scale?
The Celsius scale, also known as the centigrade scale, was introduced by Swedish astronomer Anders Celsius in 1742. It defines the freezing point of water at 0 °C and the boiling point at 100 °C under standard atmospheric conditions. The interval between these two points is divided into 100 equal parts, giving it the name “centigrade.” This scale is widely used in daily life and scientific contexts around the world.
Conversion Formulas
The Celsius Converter applies simple linear formulas to convert temperatures between Celsius and other major scales. Below are the equations you need for common conversions.
| Conversion | Formula |
|---|---|
| Celsius to Kelvin | |
| Celsius to Fahrenheit | |
| Celsius to Rankine | |
| Celsius to Delisle | |
| Celsius to Newton | |
| Celsius to Réaumur | |
| Celsius to Rømer |
Note: represents the temperature in degrees Celsius; analogous notation is used for other scales.
Built into the converter, these formulas mean you never have to do the math manually.
How to Use the Celsius Converter
Using this free online temperature conversion calculator is straightforward:
- Enter a value in the Celsius input field.
- The tool instantly displays the equivalent temperatures in Fahrenheit, Kelvin, Rankine, Delisle, Newton, Réaumur, and Rømer—all at once.
- Alternatively, you can input a temperature in any of the other supported scales, and the converter will return the corresponding value in degrees Celsius.
No downloads or sign‑ups are required. The online thermometer converter works directly in your browser.
Example Conversions
To help you see the tool in action, here are some common temperature conversions using the formulas above:
- Boiling point of water: 100 °C = 212 °F = 373.15 K
- Freezing point of water: 0 °C = 32 °F = 273.15 K
- Room temperature: Approximately 20 °C, which equals 68 °F and 293.15 K.
Why Use This Tool?
- Zero cost – it’s completely free.
- Fast and accurate – conversions are calculated in real time using the precise formulas above.
- Two‑way conversion – convert to or from Celsius with equal ease.
- All major scales – covers everything from Kelvin to the less common Rømer scale.
Whether you’re a student learning about temperature scales, a scientist handling data, or someone who just needs a quick conversion for cooking or travel, the Celsius Converter has you covered.
FAQ
1. How do I convert Celsius to Fahrenheit manually?
Multiply the Celsius value by 9/5 (or 1.8) and then add 32. For example, 100°C becomes 212°F.
2. What is 100°C in Kelvin?
Add 273.15 to the Celsius value: 100°C + 273.15 = 373.15 K.
3. Which temperature scales does the Celsius Converter support?
It supports seven scales: Kelvin, Fahrenheit, Rankine, Delisle, Newton, Réaumur, and Rømer. You can convert both from Celsius to these scales and vice versa.
4. Is the Celsius Converter free to use?
Yes, the tool is completely free to use online with no downloads or fees required.
How to Use
- Enter a numeric value in the input field and select the temperature unit you want to convert from.
- All equivalent values in other temperature units will be displayed instantly.
- Use the result for your scientific calculations, cooking recipes, weather data, or academic needs.