Celsius to Fahrenheit: The Complete Temperature Conversion Guide

Whether following a recipe from an American cookbook, checking weather abroad, or working with scientific data, temperature conversions are something most people need regularly. Our converter handles Celsius, Fahrenheit and Kelvin instantly.

The three temperature scales

Celsius (C) is the standard metric scale used in most countries. Water freezes at 0C and boils at 100C.

Fahrenheit (F) is used primarily in the United States. Water freezes at 32F and boils at 212F.

Kelvin (K) is the scientific standard. Zero Kelvin (absolute zero) is the coldest possible temperature.

The conversion formulas

• Celsius to Fahrenheit: F = (C x 9/5) + 32
• Fahrenheit to Celsius: C = (F minus 32) x 5/9
• Celsius to Kelvin: K = C + 273.15
• Kelvin to Celsius: C = K minus 273.15

How to use the temperature converter

Our converter updates all three scales simultaneously as you type. Enter a temperature in any field and the other two update instantly with no button needed.

Common temperature reference points

• Absolute zero: -273.15C / -459.67F / 0K
• Water freezes: 0C / 32F / 273.15K
• Room temperature: 20-22C / 68-72F
• Body temperature: 37C / 98.6F
• Water boils: 100C / 212F
• Moderate oven: 180C / 356F
• Very hot oven: 230C / 446F

Baking temperature conversions

• Gas Mark 2: 150C / 300F - Low / slow roast
• Gas Mark 4: 180C / 350F - Moderate / cakes
• Gas Mark 6: 200C / 400F - Hot / bread
• Gas Mark 8: 230C / 450F - Very hot / pizza

Quick mental conversions

C to F rough estimate: double the Celsius and add 30. Example: 20C is roughly (20 x 2) + 30 = 70F (exact is 68F).

F to C rough estimate: subtract 30 and halve it. Example: 100F is roughly (100 minus 30) / 2 = 35C (exact is 37.8C).

Frequently asked questions

What temperature is the same in Celsius and Fahrenheit? Minus 40 degrees is the same in both scales. This is the one point where they intersect.

Why does the US still use Fahrenheit? The US is one of only three countries that officially use the imperial system. Multiple attempts to transition to metric have not succeeded.

What is normal room temperature in Celsius? Room temperature is typically 20-22C (68-72F). Air conditioning is commonly set to 21-23C.

Why is 37C normal body temperature? Human core temperature is maintained at approximately 37C by the body's thermoregulation system. This temperature optimises enzyme function. Above 38C typically indicates fever.

How cold is -40C? Extremely cold, colder than most inhabited places ever get. The coldest temperature recorded in South Africa is approximately -18C in the Drakensberg.