Fahrenheit to Celsius and Celsius to Fahrenheit

Fahrenheit to Celsius and Celsius to Fahrenheit (F to C and C to F) Complete Guide

Fahrenheit to Celsius and Celsius to Fahrenheit conversions look hard until you see that both come from one idea: the two scales start at different points and count in different step sizes. Whether you search F to C for a weather forecast or C to F for a recipe, this guide gives you the exact formulas, a conversion chart, worked examples with negative and decimal values, mental math shortcuts with their real error sizes, and the latest verified temperature statistics for 2026.

If you only need a fast answer, use our free Fahrenheit to Celsius converter or the Celsius to Fahrenheit converter and come back here when you want to understand the method. The relationships below match the ones published by NIST, the U.S. National Institute of Standards and Technology.

What do F to C and C to F mean?

F to C means converting a temperature from degrees Fahrenheit (°F) to degrees Celsius (°C). C to F is the reverse. These two shorthand searches are among the most common unit conversions on the internet, and they rest on two fixed facts. Water freezes at 32°F and 0°C. Water boils at 212°F and 100°C at sea level under standard atmospheric pressure.

Between freezing and boiling there are 180 Fahrenheit degrees but only 100 Celsius degrees. That means one Celsius degree is 1.8 times larger than one Fahrenheit degree, because 180 divided by 100 is 1.8. NIST states the same thing: an interval of one Celsius degree corresponds to an interval of 1.8 Fahrenheit degrees. The other half of the formula, the 32, exists because the Fahrenheit scale puts its zero 32 degrees below the freezing point of water.

Quick definition for reference: the Fahrenheit scale was proposed in 1724 by the German physicist Daniel Gabriel Fahrenheit. The Celsius scale is named after the Swedish astronomer Anders Celsius, and since 2007 it has been defined through the kelvin, the official SI unit of temperature.

How do you convert Fahrenheit to Celsius (F to C)?

The Fahrenheit to Celsius formula in words is simple: subtract 32 from the Fahrenheit value, multiply the result by 5, then divide by 9. A second form, which NIST lists as the same conversion, is to subtract 32 and divide by 1.8. Both give identical answers.

Fahrenheit to Celsius steps

1. Write down the temperature in °F.
2. Subtract 32.
3. Multiply the result by 5.
4. Divide that number by 9.
5. Add the °C label and round to the precision you need.

Worked examples (F to C)

• 98.6°F to Celsius: 98.6 minus 32 is 66.6. Multiply by 5 to get 333, then divide by 9. The answer is 37°C, the traditional body temperature.
• 72°F to Celsius: 72 minus 32 is 40. Multiply by 5 to get 200, then divide by 9. The answer is 22.2°C, a comfortable room.
• 350°F to Celsius: 350 minus 32 is 318. Multiply by 5 to get 1,590, then divide by 9. The answer is 176.7°C, which recipes usually round to 175°C or 180°C.
• 38.3°F to Celsius (a decimal): 38.3 minus 32 is 6.3. Multiply by 5 to get 31.5, then divide by 9. The answer is 3.5°C, a cold but above freezing day.
• Minus 4°F to Celsius (a negative): minus 4 minus 32 is minus 36. Multiply by 5 to get minus 180, then divide by 9. The answer is minus 20°C. Keep the sign through every step.

For more detail on this direction, see our Fahrenheit to Celsius formula and chart guide, or type any value into the Fahrenheit to Celsius calculator to see the steps worked out for you.

How do you convert Celsius to Fahrenheit (C to F)?

The Celsius to Fahrenheit formula in words is: multiply the Celsius value by 9, divide by 5, then add 32. The decimal form is to multiply by 1.8 and then add 32. Because 9 divided by 5 is exactly 1.8, the two methods always agree.

Celsius to Fahrenheit steps

1. Write down the temperature in °C.
2. Multiply it by 1.8 (or multiply by 9 and divide by 5).
3. Add 32 to the result.
4. Add the °F label and round if needed.

Worked examples (C to F)

• 37°C to Fahrenheit: 37 times 1.8 is 66.6. Add 32 and you get 98.6°F.
• 25°C to Fahrenheit: 25 times 1.8 is 45. Add 32 and you get 77°F, a warm spring day.
• 180°C to Fahrenheit: 180 times 1.8 is 324. Add 32 and you get 356°F, the exact value behind the 350°F oven setting.
• 21.5°C to Fahrenheit (a decimal): 21.5 times 1.8 is 38.7. Add 32 and you get 70.7°F.
• Minus 10°C to Fahrenheit (a negative): minus 10 times 1.8 is minus 18. Add 32 and you get 14°F.

The most asked boiling point example has its own page: 100 Celsius to Fahrenheit equals 212°F. If you want the full walkthrough with more practice values, read how to convert Celsius to Fahrenheit, or use the C to F converter for instant results.

Fahrenheit to Celsius chart and Celsius to Fahrenheit chart

Use these two tables when you want a value at a glance. Results are rounded to one decimal place. Negative values are written with the word minus so they are easy to read on any screen.

Fahrenheit to Celsius chart (F to C)

Celsius to Fahrenheit chart (C to F)

Notice the pattern: every 5 degrees Celsius adds exactly 9 degrees Fahrenheit. That is the 1.8 ratio at work, and it is the fastest way to extend either chart in your head.

Which temperatures are worth memorizing?

You do not need the whole chart. A handful of anchor points lets you estimate almost any everyday temperature within a few degrees.

Minus 40 is the one value where the two scales give the same number, so minus 40°C and minus 40°F describe exactly the same cold. It is a handy proof that the formula works: subtract 32 from minus 40 to get minus 72, multiply by 5 to get minus 360, divide by 9, and you land back on minus 40.

What are the best mental math shortcuts for F to C and C to F?

Shortcuts are useful when you are reading a forecast or a thermostat and do not want to open a calculator. The catch is that most popular tricks are only accurate near one temperature. Here is how the two best known ones perform, with the actual error measured against the exact formula. For more tricks, see our guides on the fastest way to do temperature conversions and how to convert Celsius to Fahrenheit without math.

Celsius to Fahrenheit: double it and add 30

This is the classic quick estimate. It is perfect at 10°C and drifts by 0.2°F for every degree away from it.

Fahrenheit to Celsius: subtract 30 and halve it

The reverse shortcut works best near 50°F and gets less reliable in heat or deep cold.

A more accurate method

For C to F, double the Celsius value, take away one tenth of that doubled number, then add 32. Doubling and removing 10 percent is the same as multiplying by 1.8, so it is exact. For 25°C: double it to 50, remove 5 to get 45, add 32 and you reach 77°F. For F to C, subtract 32, halve the result, then add a tenth of the half. This gives 0.55 instead of 0.5556, an error of about 1 percent, so 77°F becomes 22.5 plus 2.25, which is 24.75°C against the exact 25°C.

How do you convert temperatures for cooking, weather and health?

Cooking and baking

Oven dials around the world use different scales, and a recipe written in one often needs converting to the other. Because ovens are not precise to the single degree, cooks round to the nearest common setting.

We cover this topic in depth in our guides to converting Celsius to Fahrenheit for baking and the Celsius to Fahrenheit cooking guide. A useful rule: if your oven runs hot or cold, a separate oven thermometer matters more than a one degree rounding difference.

Weather and travel

Travelers meet this problem the moment they land. A forecast of 30°C sounds mild if you think in Fahrenheit, yet it equals 86°F. A forecast of 5°C is a cool 41°F. Memorize the steps of 10°C (50°F), 20°C (68°F), 30°C (86°F) and 40°C (104°F) and you can place any forecast between them. Water also boils at lower temperatures as you gain elevation, roughly 1°F lower for every 500 feet, so a pot boils below 212°F in the mountains.

Body temperature and fever

The famous 98.6°F (37°C) figure comes from the German physician Carl Wunderlich, who published it in 1868. Modern research suggests the average is a little lower: a 2020 Stanford study reported about 97.5°F (36.4°C), and a normal range of roughly 97.7°F to 99.5°F (36.5°C to 37.5°C) is widely accepted. Many health agencies treat 100.4°F (38°C) as the fever threshold. Always use the scale printed on your thermometer, and convert only when you must compare with another source. This guide is educational and is not medical advice.

Why do two temperature scales exist?

Fahrenheit came first. In 1724 Daniel Gabriel Fahrenheit proposed a scale with 0°F at the freezing point of a brine made from water, ice and ammonium chloride, and with human body temperature near 96°F. The modern definition fixes water’s freezing point at 32°F and boiling point at 212°F.

Anders Celsius published his scale in 1742, but he set it upside down, with 0 for boiling and 100 for freezing. The scale was flipped into its familiar form shortly after: Jean Pierre Christin reversed it in 1743 and Carl Linnaeus did the same in 1744. For many years it was called centigrade. In 1948 the international body for weights and measures renamed it the degree Celsius to avoid confusion with a unit of angle in some languages.

The scale scientists use today is the kelvin. NIST explains that one Celsius degree is an interval of 1 K and that 0°C is 273.15 K. In 2019 the kelvin was redefined by fixing the Boltzmann constant at exactly 1.380649 times 10 to the power of minus 23 joules per kelvin, so temperature is no longer tied to a physical sample of water.

Today most of the world uses Celsius for daily life. Fahrenheit remains in everyday use in the United States and its territories, along with a few other places such as the Bahamas, Belize, the Cayman Islands, Palau, the Marshall Islands and the Federated States of Micronesia, according to WorldAtlas. Liberia is often listed too. Even in Celsius countries, Fahrenheit still appears in places like oven dials and cross border weather broadcasts, which is why F to C and C to F searches remain so common.

What are the latest temperature statistics for 2026?

Conversion is not only a kitchen skill. Climate reports quote Celsius, while many readers in the United States think in Fahrenheit. Here are the verified numbers worth knowing, each converted both ways. The 2025 figures come from reports covered by The Weather Network in January 2026.

The World Meteorological Organization reported that two of its eight datasets ranked 2025 as the second warmest year on record and the other six ranked it third warmest. Either way, 2025 stayed close to the 1.5°C mark, which equals 2.7°F in difference terms. The record air temperatures also show how wide the range is: the gap between the hottest and coldest readings is 145.9°C, which is 262.6°F.

Is a temperature difference converted the same way as a temperature?

No, and this trips up many people reading climate news. When a report says the planet warmed by 1.44°C, that is a change, not a position on the thermometer. To convert a change, multiply by 1.8 only and do not add 32. So 1.44°C of warming is 2.6°F of warming, not 34.6°F. The 32 only applies when you are converting an actual reading, such as 1.44°C on a thermometer, which is 34.6°F.

The same rule explains why one Fahrenheit degree is smaller than one Celsius degree. One °F equals 0.556°C, so Fahrenheit readings are naturally a little more fine grained for everyday weather, which is one reason people who grew up with it defend it.

What are the most common conversion mistakes?

• Skipping the order of operations. Always subtract 32 before multiplying when you go from F to C. Multiplying first gives a wrong answer.
• Adding 32 to a temperature difference. Only add or subtract 32 when converting a reading, never a change.
• Losing the negative sign. Convert minus 4°F step by step and keep the sign at every stage. The answer is minus 20°C.
• Using 5 divided by 9 in the wrong direction. F to C uses 5 over 9 (about 0.556). C to F uses 9 over 5 (1.8).
• Over rounding too early. Round only at the end, especially for lab, medical or cooking work.
• Trusting a shortcut outside its range. Double and add 30 is off by 6°F at 40°C, as the table above shows.

How do you convert Fahrenheit to Celsius in Excel, Google Sheets and code?

If you convert temperatures often, let software do it. In Excel and Google Sheets, with the value in cell A1:

• Fahrenheit to Celsius: =CONVERT(A1,”F”,”C”) or =(A1-32)*5/9
• Celsius to Fahrenheit: =CONVERT(A1,”C”,”F”) or =A1*9/5+32

In Python the same formulas are celsius = (f – 32) * 5 / 9 and fahrenheit = c * 9 / 5 + 32. In JavaScript they are identical. For non programmers, the fastest option is always a dedicated tool such as our F to C converter and C to F converter.

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