Temperature Converter

Enter a temperature in the input field.

Select the scale of your original value: Celsius, Fahrenheit, Kelvin, or Rankine.

Select the scale you want to convert to.

Read the result, which updates automatically as you change the value or selected scales.

Use the swap control to reverse the selected scales.

Adjust decimal precision to show more or fewer digits after the decimal point.

Copy the converted value or an equivalent value from the available results.

You can also select a preset to load a familiar temperature into the converter.

Convert temperatures between Celsius, Fahrenheit, Kelvin, and Rankine with this free online Temperature Converter. Enter a value, choose the starting and target scales, and see the result update instantly. Compare equivalent values, switch units, adjust decimal precision, and copy the result when needed.

Whether you are checking the weather, following a cooking temperature, studying science, or working with technical measurements, this tool makes temperature conversions straightforward.

Temperature describes how hot or cold something is. It is related to the average kinetic energy of the particles in a substance and is measured using different temperature scales.

The four scales supported by this converter are Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R). They describe the same physical temperature using different reference points and intervals.

Celsius (°C)

The Celsius scale is widely used in everyday life and scientific work. At standard atmospheric pressure, water freezes at 0°C and boils at 100°C.

It is the standard temperature scale in most countries and is commonly used for weather forecasts, cooking, and indoor temperature measurements.

Fahrenheit (°F)

The Fahrenheit scale is mainly used for everyday temperatures in the United States and a few other places. At standard atmospheric pressure, water freezes at 32°F and boils at 212°F.

Weather reports, household thermostats, and some cooking instructions in the United States commonly use Fahrenheit.

Kelvin (K)

Kelvin is the standard SI unit of thermodynamic temperature. It is widely used in physics, chemistry, engineering, and scientific research.

The Kelvin scale begins at absolute zero. Unlike Celsius and Fahrenheit, Kelvin does not use a degree symbol: write 273.15 K, not 273.15°K.

A temperature difference of 1 K is the same size as a difference of 1°C.

Rankine (°R)

Rankine is an absolute temperature scale that uses Fahrenheit-sized intervals. Like Kelvin, it starts at absolute zero, but its degree intervals match Fahrenheit rather than Celsius.

Rankine is encountered in some engineering and thermodynamic calculations, particularly in fields that use US customary units.

The following formulas convert a temperature between the four scales.

You can also convert directly between Celsius and Rankine:

°R = (°C + 273.15) × 9/5

°C = (°R × 5/9) − 273.15

Absolute zero is the lowest possible temperature on the thermodynamic temperature scale. It is defined as 0 K, which is equivalent to −273.15°C, −459.67°F, and 0°R.

A valid temperature cannot be below absolute zero. This converter checks the input against that limit:

Values below these limits are invalid for ordinary thermodynamic temperature conversions. The converter should display a clear validation message instead of returning a misleading result.

These presets provide familiar examples for comparing the four scales.

Water's freezing and boiling points in this table assume standard atmospheric pressure. Room temperature is an illustrative reference, not a fixed standard. Body temperature also varies by person, measurement method, time of day, and other factors; 37°C (98.6°F) is a familiar reference value, not a diagnostic threshold.

Here are some checked examples:

25°C = 77°F

0°C = 273.15 K

100°C = 212°F

68°F = 20°C

300 K = 26.85°C

540°R = 80.18°C

The displayed result may differ slightly depending on the selected decimal precision. Rounding changes how a value is shown, not the underlying conversion.