How to Convert Celsius to Fahrenheit
To convert a temperature from Celsius to Fahrenheit, multiply the Celsius value by 9, divide by 5, and add 32. In short, the formula is °F = (°C × 9/5) + 32. The converter above does it instantly — type a Celsius value, press Convert, and you get the Fahrenheit result — but the formula is easy enough to use by hand once you have seen it a few times.
The Celsius to Fahrenheit Formula
The two scales differ in two ways: their zero points and the size of each degree. Water freezes at 0 °C but 32 °F, which is why we add 32. And a Celsius degree is 1.8 times larger than a Fahrenheit degree, which is where the 9/5 (1.8) multiplier comes from. Put together, multiplying by 1.8 and adding 32 lines the two scales up exactly.
Worked Examples
Body temperature of 37 °C: 37 × 1.8 = 66.6, plus 32 = 98.6 °F. A warm 25 °C day: 25 × 1.8 = 45, plus 32 = 77 °F. Boiling water at 100 °C: 100 × 1.8 = 180, plus 32 = 212 °F. Freezing at 0 °C is 32 °F, and a chilly −10 °C is 14 °F. Notice the two scales read the same at −40°, where −40 °C equals −40 °F.
Common Celsius to Fahrenheit Values
For quick reference: 10 °C is 50 °F, 20 °C is 68 °F, 30 °C is 86 °F, and 40 °C is 104 °F. Room temperature is usually around 20–22 °C (68–72 °F), a fever starts near 38 °C (100.4 °F), and a hot summer day of 35 °C is a sweltering 95 °F. Oven temperatures convert the same way: 180 °C is about 356 °F.
Why Two Temperature Scales?
Most of the world uses Celsius, which is part of the metric system and pegs 0° and 100° to the freezing and boiling points of water. The United States and a few other regions use Fahrenheit for everyday weather and cooking. Because recipes, weather reports, thermostats, and medical readings move between the two, a quick Celsius to Fahrenheit conversion is something almost everyone needs at some point — whether you are following an American recipe, reading an overseas forecast, or checking a temperature on a device set to the other scale.
Frequently Asked Questions
What is the formula for Celsius to Fahrenheit?
°F = (°C × 9/5) + 32. Multiply the Celsius value by 1.8 and add 32.
What is 37 °C in Fahrenheit?
37 °C equals 98.6 °F, the average normal human body temperature.
At what temperature are Celsius and Fahrenheit equal?
At −40°. −40 °C is exactly −40 °F.
A Little History of the Two Scales
The Celsius scale was proposed by Swedish astronomer Anders Celsius in 1742 and sets 0° at the freezing point of water and 100° at its boiling point, which makes it clean and intuitive for science and everyday metric use. The Fahrenheit scale, devised by Daniel Gabriel Fahrenheit in 1724, places freezing at 32° and boiling at 212°, giving 180 degrees between the two points. Because Fahrenheit degrees are smaller, the scale offers finer resolution for describing air temperature without decimals, which is one reason it stuck for weather in the United States.
Cooking and Oven Temperatures
Recipes are a frequent reason to convert. A moderate oven of 180 °C is 356 °F (usually rounded to 350 °F), 200 °C is 392 °F (about 400 °F), and 220 °C is 428 °F. If you follow recipes from both metric and US sources, converting the oven temperature first prevents undercooked or burnt results. The same applies to candy and meat thermometers, where a few degrees genuinely matter.
Reading the Weather
For everyday weather, a few anchors help the numbers feel natural: 0 °C (32 °F) is freezing, 10 °C is a cool 50 °F, 20 °C is a mild 68 °F, 30 °C is a hot 86 °F, and 40 °C is a dangerous 104 °F. Once you know your own comfort range in both scales, foreign forecasts stop being a mystery. And remember the handy fixed point: −40 °C and −40 °F are the same temperature.