Temperature Converter
Convert Celsius, Fahrenheit, Kelvin and Rankine. Select the source and target units and the number of decimal places.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
°F = °C × 1.8 + 32
About this calculator
Choose the source and target units and 0, 2, 4 or 6 decimal places. Values below absolute zero (0 K = −273.15 °C = −459.67 °F = 0 °R) show an error.
Worked example
calculated with the default values below
Temperature 25 · From Celsius · Decimal places 4 · To Fahrenheit Result 77 · Celsius 25.00 °C · Fahrenheit 77.00 °F · Kelvin 298.15 K · Rankine 536.67 °R
Method and assumptions
Convert via kelvin with the scale and offset of the selected temperature unit. Absolute temperatures below 0 K are rejected. These are temperatures, not temperature differences.
Data sources
Disclaimer
These calculators give general conversion results. Rounding and the precision of the value you enter both affect the output, so treat displayed decimals as indicative rather than exact.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
°F = °C × 9÷5 + 32; K = °C + 273.15
- °C
- Temperature in Celsius
- °F
- Temperature in Fahrenheit
- K
- Temperature in kelvin
Input is first converted to Celsius: (°F − 32) × 5÷9, or K − 273.15. Rankine = K × 9÷5.
Frequently asked questions
Can I convert a temperature below absolute zero?
No. This converter rejects values below 0 K. At the boundary, −273.15 °C = −459.67 °F = 0 K = 0 °R. The decimal setting controls display rounding; it does not change the conversion.
Why is Celsius converted to kelvin by adding 273.15?
The relationship is exact: K = °C + 273.15. Thus 0 °C is 273.15 K and −273.15 °C is 0 K. The converter uses that fixed offset; it does not depend on a water triple-point measurement for each conversion.
Which inputs and limits apply to Temperature Converter?
Use the units shown beside each field. These are form limits, not recommended settings. Temperature (Celsius): -273.15–10,000; Temperature (Fahrenheit): -459.67–10,000; Temperature (Kelvin): 0–10,000; Temperature (Rankine): 0–10,000 Convert via kelvin with the scale and offset of the selected temperature unit. Absolute temperatures below 0 K are rejected. These are temperatures, not temperature differences.
What is a complete worked example for Temperature = 25; From = Celsius?
Inputs: Temperature = 25; From = Celsius; Decimal places = 4; To = Fahrenheit. Calculation: °F = °C × 9÷5 + 32; K = °C + 273.15. Results: Result = 77 °F; Celsius = 25.00 °C; Kelvin = 298.15 K; Rankine = 536.67 °R.