How do you convert Celsius to Fahrenheit?

Multiply by 9/5 and add 32. Formula: °F = (°C × 9/5) + 32. For example, 20°C = (20 × 1.8) + 32 = 68°F.

What is 0 Kelvin in Celsius?

0 K = −273.15°C, which is absolute zero — the lowest possible temperature. Nothing can be colder than absolute zero.

What temperature is the same in Celsius and Fahrenheit?

−40 degrees is the same in both Celsius and Fahrenheit. At −40°C = −40°F, the two scales intersect.

Temperature Converter

How to Use the Temperature Converter

Enter your temperature value in the Value field and select the scale you are converting from. The converter immediately shows the equivalent temperature in all four scales. The source scale is highlighted in blue.

Click Reset to clear the input and start a new conversion.

Temperature Conversion Formulas

Celsius ↔ Fahrenheit

°F = (°C × 9/5) + 32 | °C = (°F − 32) × 5/9

Example: 100°C = (100 × 1.8) + 32 = 212°F (boiling point of water at sea level).

Celsius ↔ Kelvin

K = °C + 273.15 | °C = K − 273.15

Example: 0°C = 273.15 K (freezing point of water).

Celsius ↔ Rankine

°R = (°C + 273.15) × 9/5 | °C = (°R − 491.67) × 5/9

Rankine is used in some engineering fields in the United States. Absolute zero = 0 °R = 0 K.

Temperature Scale Overview

Celsius (°C) — based on water: 0°C = freezing, 100°C = boiling. Used worldwide in everyday life and science.
Fahrenheit (°F) — used in the United States. Water freezes at 32°F, boils at 212°F. Body temperature ~98.6°F.
Kelvin (K) — SI unit of temperature. Starts at absolute zero (0 K = −273.15°C). Used in physics and chemistry.
Rankine (°R) — Fahrenheit equivalent of Kelvin. 0°R = absolute zero, degree size equals 1°F. Used in some US engineering standards.

Worked Examples

Body temperature

Normal body temperature 37°C = (37 × 1.8) + 32 = 98.6°F = 37 + 273.15 = 310.15 K.

Oven temperature

An oven set to 180°C: °F = (180 × 1.8) + 32 = 356°F. Kelvin: 180 + 273.15 = 453.15 K.

Extremely cold: liquid nitrogen

Liquid nitrogen boils at −195.79°C = −320.42°F = 77.36 K.

The −40 crossover point

−40°C = −40°F. This is the only temperature where Celsius and Fahrenheit give the same numerical value. In Kelvin: −40 + 273.15 = 233.15 K.

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?

Multiply by 1.8 (or 9/5) and add 32. Example: 25°C × 1.8 + 32 = 77°F.

What is absolute zero?

Absolute zero is 0 K = −273.15°C = −459.67°F. It is the lowest possible temperature, where particles have minimum thermodynamic energy.

Why does the US use Fahrenheit?

The US adopted the Fahrenheit scale in the 18th century and never switched to Celsius. Most other countries use Celsius as part of the metric system.

At what temperature do Celsius and Fahrenheit read the same?

At −40 degrees. Both scales intersect at −40°C = −40°F.