What Is a Temperature Calculator?
A temperature calculator converts a temperature reading between the three most common scales: Celsius, Fahrenheit, and Kelvin. The Celsius scale sets water's freezing point at 0 degrees and its boiling point at 100 degrees at standard atmospheric pressure. The Fahrenheit scale, still used primarily in the United States, sets water's freezing point at 32 degrees and boiling point at 212 degrees. The Kelvin scale is the absolute temperature scale used in science, where 0 Kelvin (absolute zero) is the point at which all thermal motion ceases.
The relationship between these scales is fixed by exact formulas. To convert Celsius to Fahrenheit, multiply by 9/5 and add 32. To convert Celsius to Kelvin, add 273.15. These formulas are exact and apply universally. For a dedicated temperature unit converter, see our Temperature Converter.
What This Calculator Does
This temperature calculator converts between Celsius, Fahrenheit, and Kelvin. Enter a value, choose the source scale, and the result appears for the target scale instantly. A full conversion table shows your input in all three scales, along with the exact formulas used.
- Inputs: A numeric temperature value and source scale
- Outputs: Converted result, all three scales, and conversion formulas
How the Conversion Works
The calculator first converts the input to Celsius as an intermediate step, then converts from Celsius to the target scale. For example, converting 98.6 degrees Fahrenheit (body temperature) to Celsius: subtract 32 to get 66.6, multiply by 5/9 to get 37 degrees Celsius. Adding 273.15 gives 310.15 Kelvin. For converting other unit types, try our Unit Converter.
Key Conversion Formulas
- Celsius to Fahrenheit: F = C x 9/5 + 32
- Fahrenheit to Celsius: C = (F - 32) x 5/9
- Celsius to Kelvin: K = C + 273.15
- Kelvin to Celsius: C = K - 273.15
- Fahrenheit to Kelvin: K = (F - 32) x 5/9 + 273.15
How to Use the Calculator
- Enter the temperature value you want to convert
- Select the scale you are converting from
- Select the scale you are converting to
- Read the result and the full conversion table
Real World Scenarios
A traveler from Europe visits the United States and sees a weather forecast of 75 degrees Fahrenheit. Converting to Celsius: (75 - 32) times 5/9 equals approximately 23.9 degrees Celsius, a comfortable warm day. A chemistry student needs to convert a reaction temperature of 25 degrees Celsius to Kelvin for a thermodynamic calculation: 25 plus 273.15 equals 298.15 Kelvin, standard room temperature. For calculating apparent temperature from heat and humidity, see our Heat Index Calculator.