Result
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Facts and limits of this method
| Celsius → Fahrenheit formula | F = C × 9/5 + 32 |
|---|---|
| Celsius → Kelvin formula | K = C + 273.15 |
| Celsius → Rankine formula | °R = (C + 273.15) × 9/5 |
| Absolute zero | 0 K = −273.15 °C = −459.67 °F = 0 °R |
When it misleads you
- Unlike most other unit converters, temperature scales aren't related by simple multiplication but by offset formulas (except the Kelvin–Rankine pair, which is proportional) — the calculation handles this automatically; you can't manually multiply a value by a "factor".
- Kelvin and Rankine are absolute scales (no negative values are physically meaningful), while Celsius and Fahrenheit allow negative temperatures; the converter doesn't block entering values below absolute zero, but the result has no physical meaning in that case.
- The word "degree" isn't used with Kelvin — it's correctly written just as "kelvins" (K, no ° sign), though interfaces sometimes simplify this for consistency.
- Rounding is applied only to the displayed result — internal calculations use the full precision of JavaScript floating-point numbers.
How it is calculated
The entered value is first converted to degrees Celsius — for example, from Fahrenheit using C = (F − 32) × 5/9, from Kelvin using C = K − 273.15.
If the "from" unit is already Celsius, this step leaves the number unchanged.
The Celsius value is then converted to the target unit using the inverse formula — for example, to Fahrenheit using F = C × 9/5 + 32.
The result is rounded to the chosen number of decimal places and updates instantly whenever the value, units or precision change.
Questions and answers
Why can't I just multiply the temperature by a factor, like with length or mass?
Because the Celsius, Fahrenheit and Kelvin scales have different zero points — for example, 0 °C corresponds to 32 °F, not 0 °F, so an offset formula is needed instead of a single multiplication.
What is the Rankine scale?
An absolute temperature scale with a degree the same size as a Fahrenheit degree, but with zero at absolute zero — used mainly in US engineering calculations.
Can the result be below absolute zero?
Mathematically the converter doesn't prevent it, but such a result has no physical meaning — absolute zero (0 K = −273.15 °C) is the lower bound of possible temperature.
Is my data sent anywhere?
No, the whole calculation runs in your browser.