Calculator guide
Convert a temperature change or difference between Celsius, kelvin, Fahrenheit and Rankine intervals. Use this for a rise or fall in temperature, not for the thermometer reading itself.
Formula or method
Output = input × source interval factor ÷ destination interval factor. ΔK = Δ°C; Δ°C = Δ°F × 5/9; Δ°F = Δ°C × 9/5. Rankine and Fahrenheit intervals are equal in size. Do not add 32 or 273.15 to a temperature difference.
How to use this calculator
- Enter the Value to convert. The interface starts with 1; replace it with your measurement or quantity. Blank, nonnumeric and out-of-range values cannot produce a result.
- Select From unit for the source unit. Match the complete label, including square/cubic units, decimal/binary prefixes or the gallon system when applicable.
- Select To unit for the destination unit, then read Converted value with its unit label.
- Try the worked example with its stated source and destination units. Results show at most eight fractional digits; very small nonzero values use scientific notation. Check the page limitations before interpreting the output.
Worked example
Select degree Fahrenheit interval (°F) → degree Celsius interval (°C), then enter 18. Compute 18 × 5/9 = 10°C of change, also 10 K. An input of −18°F gives −10°C of change.
Understanding the result
A positive interval is a rise and a negative interval is a fall. A change of 18°F is 10°C, but an absolute reading of 18°F is not 10°C.
Limitations and assumptions
- Signed temperature differences and zero are accepted. Negative intervals are not rejected using absolute-zero temperature rules.
- Absolute temperatures require offsets and belong in the Temperature Converter. This tool does not infer a heat quantity, heat capacity or safe operating temperature.
Frequently asked questions
Why is there no +32?
The Fahrenheit zero-point offset cancels when subtracting two temperatures; only the interval scale remains.
Is a 1 K change equal to a 1°C change?
Yes. Their interval sizes are equal even though their absolute zero points differ.
Can I convert an oven setting here?
No. An oven setting is an absolute temperature reading, not an interval.
Sources
Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.