Convert between Celsius, Fahrenheit and Kelvin instantly
| Reference Point | °C | °F | K |
|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 |
| Water Freezes | 0 | 32 | 273.15 |
| Room Temperature | 25 | 77 | 298.15 |
| Body Temperature | 37 | 98.6 | 310.15 |
| Water Boils | 100 | 212 | 373.15 |
| Oven – Medium | 180 | 356 | 453.15 |
A temperature converter is a tool that converts temperature values between the three main scales used globally: Celsius (metric), Fahrenheit (imperial), and Kelvin (scientific). Temperature is a fundamental physical quantity that measures the thermal energy or heat level of a substance or environment. Each scale has its own zero point and interval size.
Calculator Expert's Temperature Converter converts to all three scales simultaneously so you can see all results at once — no need to convert multiple times.
Temperature conversion is needed in cooking (recipes using °F vs °C), travel (weather forecasts in different countries), science (Kelvin for gas law equations), medicine (body temperature in different systems), and HVAC engineering. Scientists exclusively use Kelvin because it starts at absolute zero — the lowest possible temperature.
A quick rough estimate for Celsius to Fahrenheit: double the Celsius value and add 30. For example, 20°C ≈ 70°F (actual: 68°F). For exact results, use the formula (°C × 9/5) + 32. For Kelvin, simply add 273.15 to Celsius — there is no multiplication involved.
The Celsius scale was defined by Anders Celsius in 1742, originally with 0 as boiling and 100 as freezing (later reversed). Fahrenheit was developed in 1724 by Daniel Gabriel Fahrenheit. Kelvin is named after Lord Kelvin (William Thomson) and is used exclusively in science. All three are linearly related — only their zero points and step sizes differ.
Enter your temperature value in the input field, select the unit you are converting from (°C, °F, or K), then click Convert. The tool will instantly display the equivalent value in all three temperature scales simultaneously. This is particularly useful for cooking, travel, and science applications.
Kelvin cannot be negative — values below 0 K are physically impossible (absolute zero). If you enter a value that would result in a negative Kelvin, the result will show as invalid. Rankine and Réaumur scales are not included in this tool. For plasma physics or astrophysics requiring millions of degrees, scientific notation is shown.