Fahrenheit ↔ Celsius Converter
In the United States, temperature is measured almost everywhere in degrees Fahrenheit (°F) rather than Celsius. This tool converts instantly in both directions: type a value in one field and the other updates automatically.
Conversion formulas
Fahrenheit to Celsius:
°C = (°F − 32) × 5 ÷ 9
Celsius to Fahrenheit:
°F = °C × 9 ÷ 5 + 32
Quick mental shortcut: to go from °C to °F, double the value and add 30 (accurate to within a few degrees).
Common conversions worth memorizing
| Fahrenheit | Celsius | Reference |
|---|---|---|
| −40 °F | −40 °C | Both scales meet |
| 0 °F | −17.8 °C | Very cold |
| 32 °F | 0 °C | Freezing point of water |
| 50 °F | 10 °C | Cool |
| 68 °F | 20 °C | Pleasant room temperature |
| 86 °F | 30 °C | Hot summer day |
| 98.6 °F | 37 °C | Normal body temperature |
| 100 °F | 37.8 °C | Low fever / heat wave |
| 212 °F | 100 °C | Boiling point of water |
Where Fahrenheit is used in the US
The United States is one of very few countries that still use Fahrenheit in everyday life. You will encounter it mainly in three settings:
- Weather: forecasts, apps and thermostats show °F. A day at 75 °F is mild; at 95 °F it is genuinely hot.
- Cooking: US ovens and recipes give °F. A common baking temperature is 350 °F (≈ 177 °C), and 425 °F (≈ 218 °C) for roasting.
- Health: medical thermometers read in °F. Normal is 98.6 °F (37 °C); a fever is usually above 100.4 °F (38 °C).
The metric system (Celsius) remains common in science, specialized medicine and on some imported products, but rarely in daily conversation. For other US units, see our miles ↔ kilometers converter.
What to wear by temperature (°F)
- Below 32 °F (0 °C): winter coat, hat and gloves; it is freezing.
- 32–50 °F (0–10 °C): warm jacket or coat; cold weather.
- 50–65 °F (10–18 °C): sweater or light jacket; cool weather.
- 65–80 °F (18–27 °C): light clothing, short sleeves; comfortable.
- Above 85 °F (29 °C): very light clothing, stay hydrated; it is hot.
Frequently asked questions
Why does the US use Fahrenheit?
For historical reasons. The Fahrenheit scale, created in the early 18th century, became established across the English-speaking world before the metric system was adopted in Europe. The US never switched to Celsius in everyday use, unlike the United Kingdom, which did so partially.
What is normal body temperature in Fahrenheit?
About 98.6 °F, or 37 °C. A fever is generally considered to start at 100.4 °F (38 °C). Thermometers sold in the US display °F by default.
How do I convert quickly in my head?
To go from °C to °F, double the value and add 30: 20 °C → about 70 °F (exact value 68 °F). It is a handy approximation for weather, but use the converter above for an exact result.
What temperature should I set a US oven to?
Common US recipes use 350 °F (177 °C) for baking and 400–425 °F (200–218 °C) for roasting. If your oven displays °C, convert the value given in the recipe.
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