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Converters

Temperature Converter

Convert Celsius, Fahrenheit, and Kelvin in every direction with the formulas displayed, plus practical reference points.

Celsius (°C)
20
Fahrenheit (°F)
68
Kelvin (K)
293.15

Comfortable room temperature range.

°F = °C × 9/5 + 32 · K = °C + 273.15 · °C = (°F − 32) × 5/9

Exact formulas, no rounding shortcuts. Negative Kelvin is flagged as physically impossible.

When Rounding Matters

Body temperature is where casual rounding bites: 98.6 °F is 37.0 °C, but 37.5 °C is 99.5 °F, not the 99 °F some charts round to — and fever thresholds differ between the scales in everyday use. Weather reports round to whole degrees, which is fine; lab and cooking (sous-vide, sugar work) contexts are not.

Reference Temperatures

  • −40° is the point where Celsius and Fahrenheit read the same — a useful self-check.
  • 0 °C / 32 °F: water freezes. 100 °C / 212 °F: water boils (at sea level).
  • Oven "gas marks" and fan-assisted adjustments have no formulaic conversion to °C — always use the manufacturer chart.
  • Kelvin has no degree symbol: 300 K, not 300 °K, and 0 K (absolute zero) equals −273.15 °C.

Celsius, Fahrenheit and Kelvin

  1. Enter a temperature in any of the three scales.
  2. The other two scales update instantly, with the formula used shown alongside.
  3. Reference markers indicate where the value sits relative to freezing, body temperature, and boiling.
  4. Extreme inputs are handled without breaking — Kelvin never goes negative.
Formula & Technical Standard
°F = °C × 9/5 + 32 · K = °C + 273.15 · °C = (°F − 32) × 5/9

Reference Temperatures

Oven setting
Input: 180 °C
Output: 356 °F
The most common baking conversion when following recipes from another country.
Fever check
Input: 38.5 °C
Output: 101.3 °F
Crossing 38 °C (100.4 °F) is the standard fever threshold — worth knowing in both scales.

Common Questions

Why does Fahrenheit use such odd numbers in the formula?

Fahrenheit fixed 32° at water’s freezing point and 212° at boiling, so the scale is offset by 32 and compressed by 5/9 relative to Celsius.

Can temperature be negative in Kelvin?

No. 0 K is absolute zero; the tool flags negative Kelvin inputs as physically impossible.

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