Instantly convert between Celsius, Fahrenheit, Kelvin, Rankine and Réaumur. Get live results, a full conversion table, batch conversion for multiple values, and a dedicated tool for converting temperature differences — not just absolute readings.
This value is below absolute zero (0 K / -273.15 °C), which is not physically possible.
This calculator converts temperature instantly between Celsius, Fahrenheit, Kelvin, Rankine and Réaumur. Results update live as you type, and the table below shows the same reading converted into every supported scale at once. The calculator also flags any input that falls below absolute zero.
Your entered value converted into every supported temperature scale. Click a row to set it as your target scale.
| Scale | Symbol | Converted Value |
|---|
Convert a whole list of readings at once. Enter one value per line — useful for weather logs, lab data, or recipe temperatures.
Converting a change in temperature (like "the oven rose by 15°C") is not the same as converting an absolute reading, because Fahrenheit and Rankine use a different-sized degree than Celsius and Kelvin. Use this tool when you're converting an interval, not a point reading.
| Conversion | Formula |
|---|---|
| Celsius → Fahrenheit | °F = (°C × 9/5) + 32 |
| Fahrenheit → Celsius | °C = (°F − 32) × 5/9 |
| Celsius → Kelvin | K = °C + 273.15 |
| Kelvin → Celsius | °C = K − 273.15 |
| Fahrenheit → Kelvin | K = (°F − 32) × 5/9 + 273.15 |
| Kelvin → Rankine | °R = K × 9/5 |
| Celsius → Réaumur | °Ré = °C × 4/5 |
| Réaumur → Celsius | °C = °Ré × 5/4 |
Common temperature conversions people search for most often:
| Conversion | Result |
|---|---|
| 0 °C | 32 °F / 273.15 K |
| 100 °C | 212 °F / 373.15 K |
| 37 °C (body temp) | 98.6 °F / 310.15 K |
| -40 °C | -40 °F / 233.15 K |
| 20 °C (room temp) | 68 °F / 293.15 K |
| -273.15 °C (absolute zero) | -459.67 °F / 0 K |
| Reference Point | °C | °F | K |
|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 |
| Water Freezes | 0 | 32 | 273.15 |
| Average Room Temperature | 20–22 | 68–72 | 293–295 |
| Normal Human Body Temperature | 37 | 98.6 | 310.15 |
| Water Boils (sea level) | 100 | 212 | 373.15 |
| Surface of the Sun (approx.) | 5,500 | 9,932 | 5,773 |
| Scale | Symbol | Type | Common Use |
|---|---|---|---|
| Celsius | °C | Relative | Most of the world, science, weather |
| Fahrenheit | °F | Relative | United States, weather, cooking |
| Kelvin | K | Absolute | Science, physics, astronomy |
| Rankine | °R | Absolute | Engineering, thermodynamics (US) |
| Réaumur | °Ré | Relative | Historical use in Europe (largely obsolete) |
Celsius and Fahrenheit are relative scales, meaning their zero points are arbitrary (the freezing point of water, and a brine mixture, respectively). Kelvin and Rankine are absolute scales, with zero set at absolute zero — the theoretical point where all molecular motion stops — which is why they're preferred in physics and engineering.
Type the temperature you want to convert into the value field.
Select the scale you're converting from and the scale you want to convert to.
The converted value updates instantly as you type or change scales.
View your value converted into all 5 supported scales, or convert a whole list with the batch tool.
From Celsius to Fahrenheit and Kelvin to Rankine, get accurate conversions in seconds — plus a dedicated tool for converting temperature changes. Explore our full library of free conversion calculators.