How to Convert Fahrenheit to Celsius (Formula, Chart, and Examples)

Temperature is one of the few everyday measurements where two systems are still in daily use. The United States, its territories, and a handful of other places report the weather, oven settings, and body temperature in Fahrenheit, while most of the world uses Celsius. If you cook from an international recipe, travel, read a science paper, or check an overseas forecast, you eventually need to move between the two. The good news is that the conversion is simple, exact, and easy to do in your head once you know the pattern.

The Fahrenheit to Celsius formula

The exact formula has two steps. First you remove the 32 degree offset that Fahrenheit builds in at the freezing point of water, then you scale down the size of each degree. A Fahrenheit degree is smaller than a Celsius degree, so the multiplier shrinks the number:

The two numbers in the formula are not random. The 32 is where water freezes on the Fahrenheit scale, which is 0 on the Celsius scale, so subtracting it lines up the two starting points. The 5/9 (about 0.5556) corrects for the fact that there are 180 Fahrenheit degrees between freezing and boiling but only 100 Celsius degrees, and 100 divided by 180 reduces to 5/9. To go the other direction, you simply reverse the operations: F = C x 9/5 + 32. You can try both directions instantly with our Fahrenheit to Celsius converter or the reverse Celsius to Fahrenheit tool.

Worked example: convert 68 F to Celsius

Say a European recipe or thermostat shows a comfortable room temperature and you want to check it against 68 F. Follow the formula step by step:

1. Start with the Fahrenheit value: 68.
2. Subtract 32: 68 - 32 = 36.
3. Multiply by 5: 36 x 5 = 180.
4. Divide by 9: 180 / 9 = 20.
5. Result: 68 F = 20 C, a mild, comfortable room temperature.

Every conversion follows this same order. Subtract first, then scale. A common error is scaling before subtracting, which gives the wrong answer, so always handle the 32 before you touch the 5/9.

Fahrenheit to Celsius conversion chart

Most everyday temperatures fall into a predictable range. This chart covers the values you meet most often, from a freezer to a hot summer day to a fever. Bookmark it for quick reference:

Three anchor points are worth memorizing because they show up constantly: 32 F = 0 C (freezing), 98.6 F = 37 C (body temperature), and 212 F = 100 C (boiling). If you know these, you can sanity check almost any conversion at a glance.

The quick mental estimate

When you do not need to be exact, there is a shortcut you can do in your head in a second: subtract 30 and halve the result. It works because subtracting 30 is close to subtracting 32, and halving is close to multiplying by 5/9. For a typical weather range it lands within a degree or two of the real answer.

• 80 F: (80 - 30) / 2 = 25 C estimate. Exact answer is 26.7 C, so it is close.
• 60 F: (60 - 30) / 2 = 15 C estimate. Exact answer is 15.6 C.
• 90 F: (90 - 30) / 2 = 30 C estimate. Exact answer is 32.2 C.

The trick is perfect for deciding what to wear or whether a forecast means shorts or a sweater. For cooking, medical readings, or science, use the exact formula instead, because a one or two degree error can matter.

Where you will actually use this: cooking, travel, and health

The formula matters most in three everyday situations. In the kitchen, many recipes, ovens, and cookbooks from outside the United States list temperatures in Celsius, so a US oven set in Fahrenheit needs a quick translation. When you travel, forecasts, car dashboards, and hotel thermostats abroad almost always show Celsius, and knowing that 30 C is a hot beach day while 5 C means bring a coat saves you from packing wrong. For health, a thermometer bought overseas or a clinic chart may read in Celsius, so it helps to know that 37 C is normal and anything above about 38 C signals a fever.

Oven settings are the conversion people look up most, because getting them wrong can ruin a dish. Here are the common baking temperatures side by side:

Because ovens are not precise instruments, cooks usually round Celsius oven settings to the nearest 5 or 10 degrees, so 177 C becomes a tidy 180 C and 191 C becomes 190 C. That rounding is fine for baking. For body temperature, medication doses, or laboratory work, keep the exact decimal from the formula instead, since even a small difference can change the meaning of a reading.

Common mistakes and good to know

A few small slip-ups cause almost all wrong answers. Watch for these:

• Multiplying before subtracting. Always do (F - 32) first, then apply 5/9. Order matters.
• Mixing up the two multipliers. Use 5/9 to go from F to C, and 9/5 to go from C to F. They are not interchangeable.
• Forgetting negative results. Below 32 F the Celsius value goes negative. For example, 0 F is about -17.8 C, not a positive number.
• Rounding too early. If you round mid calculation, small errors add up. Keep the decimal until the final step.

One more useful fact: the two scales cross at a single point. -40 F equals -40 C exactly, the only temperature where both scales read the same number. It is a handy check that your formula is set up correctly. Temperature is just one of many everyday conversions worth mastering. If you cook or measure a lot, our guides on how many grams are in a cup and how many milliliters are in an ounce round out the kitchen math. For the reverse temperature direction, see our companion post on Celsius to Fahrenheit conversion.

Once you know the formula, converting Fahrenheit to Celsius takes only a few seconds. Remember the pattern: subtract 32, then multiply by 5/9. Memorize the three anchor points at 32, 98.6, and 212 F, keep the subtract 30 and halve trick handy for quick estimates, and reach for the converter above whenever you need an exact, instant answer.