Convert Fahrenheit to Celsius instantly, see the exact formula, use common temperature charts, and compare weather, cooking and body-temperature references.
The exact conversion is °C = (°F − 32) × 5/9. Use the calculator for fast answers, then use the tables below for common values such as 32°F, 98.6°F, 212°F and oven temperatures. Current source check: June 27, 2026.
Enter a temperature or use a quick value.
A key anchor point for everyday temperature conversion.
A common indoor reference used in weather and comfort contexts.
Normal body temperature varies; this is a common average reference.
A familiar water-boiling reference at sea level.
Fahrenheit to Celsius Formula
Fahrenheit and Celsius use different zero points and different degree sizes. That is why the conversion has two steps: adjust the zero point by subtracting 32, then scale the result by 5/9.
For example, to convert 98.6°F: subtract 32 to get 66.6, then multiply by 5/9 to get 37°C.
Why the formula works
The formula is not arbitrary. On the Fahrenheit scale, water freezes at 32°F and boils at 212°F under standard everyday reference conditions. That gives a 180-degree Fahrenheit gap between freezing and boiling. On the Celsius scale, the same reference points are 0°C and 100°C, a 100-degree Celsius gap. The scale ratio is therefore 100/180, which simplifies to 5/9. Subtracting 32 removes the Fahrenheit offset; multiplying by 5/9 changes the size of the degree interval.
Decimal version
The decimal 0.5556 is a rounded version of 5/9. Use the fraction 5/9 for exact work, and use the decimal version only when a rounded practical result is enough.
Step-by-Step Examples
32°F to °C
(32 − 32) × 5/9 = 0°C. This is the freezing point reference.
68°F to °C
(68 − 32) × 5/9 = 20°C. This is a common indoor temperature.
98.6°F to °C
(98.6 − 32) × 5/9 = 37°C. Body temperature varies by person and time of day.
350°F to °C
(350 − 32) × 5/9 = 176.7°C, usually rounded to about 177°C for oven conversion.
Fahrenheit to Celsius Chart
This quick chart covers weather, home, body-temperature, water and oven references. Values are rounded to one decimal place unless the conversion is exact enough to show cleanly.
| Fahrenheit | Celsius | Typical use | Conversion note |
|---|---|---|---|
| -40°F | -40°C | Extreme cold | The two scales meet at -40. |
| 0°F | -17.8°C | Very cold weather | Below typical household freezer temperatures. |
| 32°F | 0°C | Freezing point reference | Useful anchor for mental conversion. |
| 50°F | 10°C | Cool day | Jacket weather for many people. |
| 68°F | 20°C | Room temperature | Common indoor reference. |
| 86°F | 30°C | Warm day | Simple mental anchor: 86°F is 30°C. |
| 98.6°F | 37°C | Body temperature reference | Normal body temperature has a range. |
| 100.4°F | 38°C | Fever reference | MedlinePlus notes 100.4°F often means fever. |
| 212°F | 100°C | Boiling water reference | Boiling point varies with pressure and altitude. |
| 350°F | 176.7°C | Oven setting | Often rounded to 175°C or 180°C depending on oven controls. |
| 400°F | 204.4°C | Hot oven | Often rounded to about 200°C. |
| 450°F | 232.2°C | Very hot oven | Often rounded to about 230°C. |
Practical Temperature References
Temperature conversion is most useful when the number is tied to a real situation. These references help students, travelers, cooks and science learners interpret Fahrenheit values quickly.
| Context | Fahrenheit | Celsius | What to remember |
|---|---|---|---|
| Cold food storage | 40°F | 4.4°C | Often used as a refrigerator safety threshold in food guidance. |
| Normal body reference | 98.6°F | 37°C | Average reference; normal temperature varies by person and time of day. |
| Fever reference | 100.4°F | 38°C | MedlinePlus notes this often means fever caused by illness or infection. |
| Whole cuts of beef, pork, lamb or veal | 145°F | 63°C | FoodSafety.gov lists this with a 3-minute rest for steaks, roasts and chops. |
| Ground meat and egg dishes | 160°F | 71°C | Used for ground meat and many egg dishes in safe minimum temperature charts. |
| Poultry and leftovers | 165°F | 74°C | FoodSafety.gov lists 165°F / 74°C for poultry and leftovers. |
| Moderate oven | 350°F | 176.7°C | Round to the nearest available oven setting. |
Fast Mental Conversion
The exact formula is best for calculators and homework. For a quick estimate, subtract 30 from Fahrenheit and divide by 2. This is not exact, but it is fast enough for everyday weather checks.
| Fahrenheit | Exact Celsius | Quick estimate | Error |
|---|---|---|---|
| 50°F | 10°C | (50 − 30) ÷ 2 = 10°C | 0°C |
| 68°F | 20°C | (68 − 30) ÷ 2 = 19°C | 1°C low |
| 86°F | 30°C | (86 − 30) ÷ 2 = 28°C | 2°C low |
| 104°F | 40°C | (104 − 30) ÷ 2 = 37°C | 3°C low |
Precision tip: For science, medicine and food safety, use the exact formula or a calibrated thermometer reading. Mental conversion is only a quick estimate.
Celsius to Fahrenheit Conversion
The reverse conversion is useful when a recipe, weather forecast or lab note gives Celsius and you need Fahrenheit. The steps are the reverse of Fahrenheit to Celsius: multiply Celsius by 9/5, then add 32.
Example: 20°C × 9/5 + 32 = 68°F. This is why 20°C is a useful room-temperature anchor.
| Celsius | Fahrenheit | Common meaning | Reverse formula note |
|---|---|---|---|
| 0°C | 32°F | Water freezing reference | 0 × 9/5 + 32 = 32. |
| 10°C | 50°F | Cool day | 10 × 9/5 + 32 = 50. |
| 20°C | 68°F | Room temperature reference | 20 × 9/5 + 32 = 68. |
| 30°C | 86°F | Warm weather | 30 × 9/5 + 32 = 86. |
| 100°C | 212°F | Boiling water reference | 100 × 9/5 + 32 = 212. |
How Fahrenheit And Celsius Differ
Both Fahrenheit and Celsius measure temperature, but they were built around different reference choices. Fahrenheit is still common for everyday weather, indoor thermostats and cooking in the United States. Celsius is used by most countries and is the standard everyday temperature scale in science, healthcare, education and international reporting.
Different zero points
Water freezes at 32°F but 0°C, so the conversion must account for a 32-degree offset.
Different degree sizes
A Celsius degree is larger than a Fahrenheit degree. A 9°F change equals a 5°C change.
Same value at -40
-40°F equals -40°C, a useful fact for cold-weather comparisons.
Kelvin connection
Kelvin uses the same interval size as Celsius, so K = C + 273.15.
Practical Uses For Fahrenheit To Celsius Conversion
Fahrenheit to Celsius conversion becomes easier when you connect the numbers to real decisions. Weather forecasts, recipes, thermometers and science assignments all use the same formula, but each context has a different tolerance for rounding.
Weather and travel
Travelers moving between the United States and Celsius-using countries often need fast weather conversion. 50°F is 10°C, 68°F is 20°C and 86°F is 30°C.
Cooking and baking
American recipes often use Fahrenheit oven settings. 350°F converts to 176.7°C, while 400°F converts to 204.4°C. Round to the nearest available oven setting.
Science classes
Science work usually uses Celsius or Kelvin. Convert Fahrenheit first, then add 273.15 if an absolute temperature in Kelvin is required.
Medicine and health
A common body-temperature reference is 98.6°F, or 37°C. Use clinical guidance and a reliable thermometer for health decisions.
Special Temperature Points
These values are useful anchors because they appear often in homework, science examples, weather reports, medicine, cooking and general measurement questions.
| Temperature point | Fahrenheit | Celsius | Why it matters |
|---|---|---|---|
| Absolute zero | -459.67°F | -273.15°C | The theoretical zero of thermal energy; use Kelvin for absolute temperature work. |
| Equal point | -40°F | -40°C | The only temperature where Fahrenheit and Celsius have the same number. |
| Water freezes | 32°F | 0°C | The easiest anchor for remembering the Fahrenheit offset. |
| Room-temperature reference | 68°F | 20°C | A practical comfort and indoor-temperature benchmark. |
| Normal body reference | 98.6°F | 37°C | A common average body-temperature reference, not a single fixed value for everyone. |
| Water boils | 212°F | 100°C | A familiar reference at sea level; boiling temperature changes with pressure and altitude. |
Common Conversion Mistakes
- Forgetting to subtract 32: Multiplying Fahrenheit by 5/9 directly gives the wrong answer because Fahrenheit has a different zero point.
- Using 9/5 in the wrong direction: Fahrenheit to Celsius uses 5/9; Celsius to Fahrenheit uses 9/5.
- Rounding too early: Keep extra decimals during calculation, then round the final answer.
- Confusing weather and oven rounding: Weather is often fine to one decimal or whole degrees, while recipes must match the available oven controls.
- Treating body temperature as one exact number: 98.6°F / 37°C is a reference point, but normal body temperature varies.
Official Sources Checked
- National Weather Service temperature converter for weather conversion context.
- National Weather Service temperature conversion formula PDF for Fahrenheit, Celsius and Kelvin formulas.
- NIST metric practice guide for the Fahrenheit to Celsius conversion relationship.
- MedlinePlus body temperature norms for 98.6°F / 37°C and fever context.
- FoodSafety.gov safe minimum internal temperatures for cooking references.
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Fahrenheit to Celsius FAQs
The formula is °C = (°F − 32) × 5/9. Subtract 32 from the Fahrenheit value, then multiply by 5/9.
32°F equals 0°C. This is the freezing point reference used in many temperature charts.
98.6°F equals 37°C. MedlinePlus notes that normal body temperature varies by person, age, activity and time of day.
100.4°F equals 38°C. MedlinePlus says a temperature over 100.4°F most often means fever caused by infection or illness.
Use °F = °C × 9/5 + 32. For example, 20°C × 9/5 + 32 = 68°F.
Ovens often use preset marks, and real oven temperatures vary. For example, 350°F is exactly 176.7°C, but many recipes round it to 175°C or 180°C depending on the appliance.
-40°F equals -40°C. This is the point where both scales show the same number.
No. Accuracy depends on the thermometer, calibration and measurement method. Celsius and Fahrenheit can both be precise; they simply use different reference points and degree sizes.
About RevisionTown: RevisionTown creates practical calculators, converters and study resources for mathematics, science, exams and everyday measurement. This converter uses the standard Fahrenheit to Celsius formula and adds context so students can understand the result, not just copy a number.
