Temperature ConverterFree online other calculator — instant results, no sign-up
Convert Celsius, Fahrenheit and Kelvin.
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About the Temperature Converter
The Temperature Converter converts a temperature between Celsius, Fahrenheit and Kelvin. Select the starting and target scales to express the same temperature in different units. With the default settings, it converts 20 Celsius to 68 Fahrenheit.
- Temperature
- The temperature value to convert, measured in the scale selected under From, with a default of 20.
- From
- The input temperature scale—Celsius (°C), Fahrenheit (°F) or Kelvin (K)—with Celsius selected by default.
- To
- The output temperature scale—Fahrenheit (°F), Celsius (°C) or Kelvin (K)—with Fahrenheit selected by default.
Formula and method
For the default Celsius-to-Fahrenheit conversion: F = C × 9/5 + 32, so F = 20 × 9/5 + 32 = 68. Other conversion relationships are C = (F − 32) × 5/9, K = C + 273.15 and C = K − 273.15.
- CTemperature expressed in degrees Celsius (°C).
- FTemperature expressed in degrees Fahrenheit (°F).
- KTemperature expressed in kelvins (K), written without a degree symbol.
Use the selected source and target scales to choose the conversion relationship. Celsius and Fahrenheit require both a scale factor and an offset; Celsius and Kelvin differ only by an offset. Fahrenheit-to-Kelvin and Kelvin-to-Fahrenheit conversions can pass through Celsius. For the default inputs, multiply 20 by 9/5 and add 32 to obtain 68 Fahrenheit. Selecting the same source and target scale leaves the value unchanged.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Temperature20
- FromCelsius
- ToFahrenheit
Results
- Result68 Fahrenheit
How to use the Temperature Converter
- 1Enter 20 in Temperature to follow the default example.
- 2Select Celsius under From to identify the input as degrees Celsius.
- 3Select Fahrenheit under To to choose the output scale.
- 4Read the Result: 68 Fahrenheit, equivalent to 20 Celsius.
Reading your result
The Result row gives the converted temperature followed by the target scale. In the default example, Result = 68 Fahrenheit means 68 °F, which represents the same temperature as 20 °C—not a temperature increase. Always read the number together with its scale.
Limitations
These formulas convert temperature readings, not temperature differences; differences must be converted without the additive offsets. The conversion does not improve the accuracy of the original measurement, and displayed decimals may be rounded. For ordinary physical temperatures, values below absolute zero—0 K, −273.15 °C or −459.67 °F—are not valid; do not assume the tool rejects such inputs.
Common questions
Why does 20 Celsius become 68 Fahrenheit?+
The Fahrenheit scale has a different degree size and zero point. Applying F = C × 9/5 + 32 gives 20 × 9/5 + 32 = 68 °F.
How does the calculator convert Fahrenheit to Kelvin?+
First convert Fahrenheit to Celsius, then add 273.15: K = (F − 32) × 5/9 + 273.15.
Should Kelvin results include a degree symbol?+
No. The unit is the kelvin, written K, whereas Celsius and Fahrenheit use °C and °F.
Can I use this converter for a temperature change rather than a reading?+
Not directly when the conversion applies an offset. For a temperature change, multiply a Celsius difference by 9/5 to get a Fahrenheit difference, or multiply a Fahrenheit difference by 5/9 to get a Celsius difference. Celsius and Kelvin differences have the same numerical value.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.