Private by design: this tool runs in your browser. ToolSyn does not receive the values, text or files you process here.
About this tool
Enter a temperature and select the source and target scale. The converter updates immediately and warns if the value is below physical absolute zero.
How to use it
- Enter a temperature value.
- Choose the source and target scales.
- Read the converted result or swap the scales.
Temperature formulas
°F = (°C × 9 ÷ 5) + 32
°C = (°F − 32) × 5 ÷ 9
K = °C + 273.15
Worked example
Example: 0°C equals 32°F and 273.15 K.
Good to know
Kelvin is written without a degree symbol. Absolute zero is 0 K, equal to −273.15°C.
Need more explanation or examples?
Browse more ToolSyn guides →Frequently asked questions
At what value are Celsius and Fahrenheit equal?
They are equal at −40.
Does Kelvin use a degree symbol?
No. It is written K.
Can temperature be below absolute zero?
The calculator can show the mathematical conversion but displays a physical warning.
Tool logic and explanatory wording reviewed on July 19, 2026.