Temperature converter
Convert Celsius, Fahrenheit, and Kelvin with the exact formulas shown.
What this calculator covers
Use this temperature converter when you need the exact relationship between Celsius, Fahrenheit, and Kelvin instead of a rounded shortcut.
The walkthrough normalizes the source value into Kelvin first, then converts that Kelvin value into the target scale so the offset-based formulas stay visible.
Frequently asked questions
- What is absolute zero and why can't you go below it?
- Absolute zero (0 K, or about −273.15 °C / −459.67 °F) is the lowest theoretically possible temperature, where molecular motion reaches its minimum. No physical system can be cooled below it, so the calculator rejects any input that would produce a sub-zero Kelvin result.
- Why does converting between Celsius and Fahrenheit require an offset, not just multiplication?
- The two scales have different zero points. Celsius places zero at the freezing point of water, while Fahrenheit places it at a different reference entirely. That offset (32°F) must be added or subtracted before the 9/5 ratio is applied, which is why a simple multiplication alone gives the wrong answer.
- What is Kelvin used for?
- Kelvin is the SI base unit for thermodynamic temperature and is used in scientific and engineering contexts where calculations require an absolute scale — including gas laws, thermodynamics, and astrophysics. Unlike Celsius and Fahrenheit, Kelvin has no negative values under normal physical conditions.
- Is the conversion exact or rounded?
- The conversion is exact — the calculator uses the defined relationships between scales (0 °C = 273.15 K, 0 °F = 255.372… K) without approximation, and rounds only the displayed output.
Tool
Run the calculation
Result
RESULT · CONVERTED TEMP
â„–123
Primary result
22.222222 C
72 F converts to 22.222222 C using Kelvin as the shared base unit.
- Input
- 72 F (Fahrenheit)
- Kelvin value
- 295.372222 K
- Converted value
- 22.222222 C (Celsius)
Step-by-step solution
- 1.Start with 72 F in Fahrenheit.
- 2.Normalize it to Kelvin: ((72 - 32) x 5 / 9) + 273.15 = 295.372222 K.
- 3.Convert the kelvin value into Celsius: 295.372222 - 273.15 = 22.222222 C.
Walkthrough
Visual walkthrough
temperature conversions normalize the source value into one shared base unit before expressing that same quantity in the target unit.
01
Read the source temperature
The calculator starts from 72 F in Fahrenheit.
72 F
02
Normalize to Kelvin
((72 - 32) x 5 / 9) + 273.15 = 295.372222 K
Using kelvin as the common base keeps every supported temperature on one exact path.
03
Express the result in Celsius
295.372222 - 273.15 = 22.222222 C
The exact formula preserves scale offsets without approximation.
22.222222 C