Unit Converter
Temperature
Fahrenheit
degrees Fahrenheit
This Celsius to Fahrenheit calculator converts any temperature instantly, with the exact formula shown alongside every result. Type a value, pick your direction, and press Convert. It works both ways: Celsius to Fahrenheit and Fahrenheit to Celsius.
Below you will find the exact conversion formula, a reference table for common temperatures, practical examples for cooking, weather, travel, and medicine, and answers to the questions people ask most.
The Celsius to Fahrenheit Formula
To convert Celsius to Fahrenheit, multiply the Celsius value by 9/5, then add 32.
°F = (°C × 9/5) + 32
Example: 25°C = (25 × 1.8) + 32 = 45 + 32 = 77°F
To go the other direction, from Fahrenheit to Celsius, subtract 32 first, then multiply by 5/9.
°C = (°F − 32) × 5/9
Example: 98.6°F = (98.6 − 32) × 0.5556 = 66.6 × 0.5556 = 37°C
The reason this is not a simple multiplication is that the two scales start at different zero points. Water freezes at 0°C but at 32°F. On top of that, one degree Celsius equals 1.8 degrees Fahrenheit, so the gap between readings widens as the temperature rises.
How to Use the Calculator
Enter a number in the input field. Select C to F if you are converting Celsius to Fahrenheit, or F to C if you are going the other direction. Press the Convert button or hit Enter on your keyboard. The result appears below the button with the formula that produced it.
The tool accepts decimals, negative numbers, and large values. It works for everyday temperatures like weather and cooking, and for scientific or industrial ranges too.
Quick Reference Conversion Table
These are the temperatures people look up most often. Bookmark this page and come back whenever you need a fast answer.
| Description | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Absolute zero | -273.15 | -459.67 |
| Extremely cold winter day | -40 | -40 |
| Very cold weather | -20 | -4 |
| Cold winter day | -10 | 14 |
| Freezing point of water | 0 | 32 |
| Cold day | 10 | 50 |
| Mild spring weather | 15 | 59 |
| Room temperature | 20 | 68 |
| Warm summer day | 25 | 77 |
| Hot day | 30 | 86 |
| Very hot day | 35 | 95 |
| Normal body temperature | 37 | 98.6 |
| Extreme heat | 40 | 104 |
| Pasteurisation temperature | 72 | 161.6 |
| Boiling point of water (sea level) | 100 | 212 |
| Oven: low heat | 150 | 302 |
| Oven: medium heat | 180 | 356 |
| Oven: high heat | 220 | 428 |
Useful fact -40 is the only temperature that reads the same on both scales. At that point, the two scales cross. Colder than that, Celsius reads a lower number than Fahrenheit. Warmer than that, Fahrenheit reads higher.
Mental Math Shortcut
If you need a rough answer without a calculator, double the Celsius value and add 30. This works well for typical weather temperatures between -10°C and 40°C, giving you an answer within a few degrees.
Quick estimate: °F ≈ (°C × 2) + 30
Example: 22°C ≈ (22 × 2) + 30 = 74°F (actual: 71.6°F)
For oven temperatures or medical readings, use the exact formula or this calculator. The shortcut loses accuracy above 40°C or below -10°C.
When You Need to Convert Temperatures
Cooking and Baking
American recipes almost always list oven temperatures in Fahrenheit. Most of the rest of the world uses Celsius. If you follow a recipe from a US cookbook, a 350°F oven is 177°C. A 425°F oven is 218°C. Getting this wrong by even 20 degrees changes how bread browns, how a cake sets, or whether a roast reaches a safe internal temperature.
Food safety depends on reaching the right internal temperature. Chicken needs to reach 74°C (165°F) to destroy harmful bacteria. Pork is safe at 63°C (145°F). Ground beef requires 71°C (160°F). These numbers come from health authorities and do not change based on region, so cooks who work across recipe sources need to convert accurately.
Weather and Travel
The United States reports weather in Fahrenheit. If you travel there from a country that uses Celsius, a forecast of 95°F sounds extreme until you convert it to 35°C, which is a hot but recognisable summer day. Going the other direction, a European forecast of 38°C in a heatwave translates to 100.4°F for American audiences.
If you use a weather app set to the wrong unit, packing clothes for a trip becomes guesswork. A 20°C day is a jacket-optional spring afternoon. A 20°F day is well below freezing and requires a heavy coat.
Medical Use
Normal human body temperature is 37°C, which equals 98.6°F. A fever starts at 38°C (100.4°F). A temperature of 39°C (102.2°F) warrants medical attention if it persists. Doctors, nurses, and patients in different countries use different scales on thermometers, so knowing both values helps when comparing readings or following international medical guidance.
Science and Engineering
Laboratory work and engineering projects often cross borders. A specification written in one scale needs to convert cleanly to the other. Steel hardening, for example, requires heating to 800 to 900°C, which is 1,472 to 1,652°F. Industrial equipment, chemical processes, and manufacturing all depend on accurate temperature conversion to match international standards.
History of the Two Scales
Daniel Gabriel Fahrenheit, a German physicist working in the Netherlands, created his temperature scale in 1724. He set zero degrees at the lowest temperature he could reproduce in his lab using a mixture of ice, water, and ammonium chloride. He set 96 degrees at what he believed was human body temperature. Water ended up freezing at 32°F and boiling at 212°F on this scale.
Anders Celsius, a Swedish astronomer, proposed his scale in 1742. He placed zero at the boiling point of water and 100 at the freezing point. After his death, the scale was reversed to its current form, with 0°C as the freezing point and 100°C as the boiling point. This 100-degree interval between two reliable reference points made Celsius easier to use in science.
The Celsius scale was adopted as part of the metric system and spread across most of the world during the 19th and 20th centuries. The United Kingdom switched officially in the 1960s. Most other countries followed during their transitions to the metric system. The United States passed the Metric Conversion Act in 1975 but made adoption voluntary, so Fahrenheit remains the everyday standard there today.
Which Countries Use Fahrenheit
As of 2026, the countries that use Fahrenheit as their primary scale for everyday temperature are the United States, the Bahamas, the Cayman Islands, Palau, the Federated States of Micronesia, and the Marshall Islands. Several British territories, including Bermuda, Anguilla, and the British Virgin Islands, use both scales.
Canada officially uses Celsius for weather and public life, but Fahrenheit still appears on oven dials, in some news broadcasts near the US border, and among older generations. The United Kingdom is similar: the official standard is Celsius, but British tabloids will sometimes report a summer heatwave in Fahrenheit because 106°F feels more alarming than 41°C to readers who grew up with both scales.
Scientists, engineers, and medical professionals worldwide use Celsius or Kelvin for all technical work, regardless of what their country uses for everyday temperatures. Fahrenheit does not appear in scientific literature.
Frequently Asked Questions
What is the formula to convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (or 1.8), then add 32. The formula written out is: °F = (°C × 9/5) + 32. For 25°C: (25 × 1.8) + 32 = 77°F.
What is 100 degrees Celsius in Fahrenheit?
100°C is 212°F. This is the boiling point of water at sea level under standard atmospheric pressure. At higher altitudes, water boils at a lower temperature because atmospheric pressure is reduced.
What is normal body temperature in both scales?
Normal body temperature is 37°C or 98.6°F when measured orally. A fever starts at 38°C (100.4°F). Temperatures above 39°C (102.2°F) that persist for more than a day usually require medical attention.
Is there a temperature where Celsius and Fahrenheit show the same number?
Yes. Both scales read -40 at the same temperature. Below that point, Celsius values are numerically lower than Fahrenheit values. Above it, Fahrenheit values are always higher than Celsius values for the same temperature.
What is 37 degrees Celsius in Fahrenheit?
37°C equals 98.6°F. This is normal human body temperature. It comes up often in medical contexts when comparing thermometer readings between countries that use different scales.
How do I quickly convert Celsius to Fahrenheit in my head?
Double the Celsius value and add 30. This gives a rough answer fast. For 20°C: (20 × 2) + 30 = 70°F. The exact answer is 68°F. The shortcut works well for weather temperatures but loses accuracy at extremes. Use the calculator above for anything where precision matters.
Why does the United States still use Fahrenheit?
Mostly because the 1975 Metric Conversion Act made the switch to metric units voluntary rather than mandatory. Industries chose not to retrain staff or retool equipment. The scale has been in daily use for over 250 years in the US, and changing it would require updating weather broadcasts, thermostats, ovens, and everyday language simultaneously. Other countries made the switch mandatory, which is why the transition stuck.
What is 0 degrees Celsius in Fahrenheit?
0°C is 32°F. This is the freezing point of water at standard atmospheric pressure. Below 0°C (32°F), standing water will freeze. Above it, ice will melt.
