Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, and Rankine temperatures.
Convert temperature
Converted value
0 °C equals 32 °F.
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Convert temperature scales
Enter a temperature and select its current and desired scales. The converter supports Celsius and Fahrenheit for everyday use, Kelvin for SI and scientific work, and Rankine for absolute-temperature calculations using Fahrenheit-sized intervals.
The tool accepts negative values where the selected scale permits them, but it rejects temperatures below absolute zero.
Conversion model
Temperature scales cannot be converted with a single multiplication factor because their zero points differ. The shared converter represents every scale with a scale and offset relative to Celsius, then converts from that common baseline.
For example, Fahrenheit to Celsius subtracts 32 and multiplies by five-ninths. Celsius to Fahrenheit multiplies by nine-fifths and adds 32. Kelvin differs from Celsius by exactly 273.15.
Absolute temperature
Absolute zero is the theoretical lower limit of thermodynamic temperature. It is 0 kelvin, 0 degrees Rankine, −273.15 degrees Celsius, or −459.67 degrees Fahrenheit.
The calculator enforces that boundary after translating the input into the common base scale. This prevents a value from bypassing the check merely by choosing a different input unit.
Precision
Results display up to 12 significant digits. For measurements from a household thermometer or weather report, fewer digits are usually appropriate. Scientific work should follow the uncertainty and significant-figure rules of the source measurement.
Frequently asked questions
What temperature is the same in Celsius and Fahrenheit?
Negative 40 degrees is the same on both scales, so −40 °C equals −40 °F.
What is absolute zero on each temperature scale?
Absolute zero is −273.15 °C, −459.67 °F, 0 K, and 0 °R. The converter rejects values below that physical limit.
Why does temperature conversion use addition as well as multiplication?
Celsius and Fahrenheit have different interval sizes and different zero points. Converting between them therefore requires both scaling and an offset.
Should Kelvin temperatures include a degree symbol?
No. The SI unit name and symbol are kelvin and K, without the word degree or a degree symbol.