Temperature Converter

Multiply the Celsius value by 9, divide by 5, and add 32. For example, 50 °C becomes 50 × 9/5 + 32 = 122 °F. Other handy reference points: 0 °C is 32 °F, 100 °C is 212 °F, and a normal body temperature of 37 °C is 98.6 °F. This converter applies the formula instantly for any value you enter.

Subtract 32 from the Fahrenheit value, multiply by 5, and divide by 9. So 68 °F becomes (68 − 32) × 5/9 = 20 °C. Common anchors: 32 °F is 0 °C, 212 °F is 100 °C, and 98.6 °F is 37 °C. Enter any Fahrenheit value above and pick Celsius as the target to get the exact result.

Kelvin is the absolute temperature scale used in science: 0 K is absolute zero, where molecular motion stops. Kelvin uses the same degree size as Celsius, so K = °C + 273.15 and 0 °C equals 273.15 K. In Fahrenheit, absolute zero is −459.67 °F. Water boils at 373.15 K, and negative Kelvin temperatures do not exist.

Rankine (°R) is Fahrenheit-based but starts at absolute zero, so °R = °F + 459.67; it still appears in some US engineering thermodynamics work. Réaumur (°Ré) sets water's freezing point at 0 and its boiling point at 80, so °Ré = °C × 4/5; it survives mainly in European cheese making and sugar-syrup production. This converter supports both.

Absolute zero — 0 K, −273.15 °C, −459.67 °F, or 0 °R — is the lower limit of temperature, where thermal motion reaches its minimum. It cannot be physically reached or undercut. If you enter a value below absolute zero, this converter shows an explicit error instead of a meaningless number.

−40 is the one point where the two scales meet. Solving x = x × 9/5 + 32 gives x = −40, so −40 °C equals −40 °F exactly. It is a handy sanity check: if a thermometer shows −40 in both scales, both readings agree. Everywhere else the scales differ, which is why using the exact formulas matters.