Fahrenheit to Celsius Converter
Convert between Fahrenheit and Celsius instantly. Includes weather, cooking, medical fever, and science reference tables.
°F → °C
°C → °F
Weather Temperature Reference
| °F | °C | Conditions | What to Wear |
|---|---|---|---|
| 0°F | -17.8°C | Extreme cold | Full winter gear, limit exposure |
| 20°F | -6.7°C | Freezing cold | Heavy coat, gloves, hat |
| 32°F | 0°C | Freezing point of water | Winter coat, watch for ice |
| 50°F | 10°C | Cool | Jacket or sweater |
| 60°F | 15.6°C | Mild | Light jacket, long sleeves |
| 70°F | 21.1°C | Comfortable | T-shirt, light layers |
| 80°F | 26.7°C | Warm | Short sleeves, shorts |
| 90°F | 32.2°C | Hot | Light clothing, stay hydrated |
| 100°F | 37.8°C | Very hot | Minimal clothing, seek shade |
| 110°F | 43.3°C | Extreme heat | Dangerous — limit outdoor activity |
Cooking Temperature Reference
| Food / Setting | °F | °C | Gas Mark |
|---|---|---|---|
| Water boils | 212°F | 100°C | — |
| Low oven / slow cook | 250–300°F | 120–150°C | ½ – 2 |
| Moderate oven | 325–375°F | 160–190°C | 3 – 5 |
| Hot oven | 400–450°F | 200–230°C | 6 – 8 |
| Chicken (safe internal) | 165°F | 74°C | — |
| Beef (medium rare) | 135°F | 57°C | — |
| Beef (medium) | 145°F | 63°C | — |
| Pork (safe internal) | 145°F | 63°C | — |
| Pizza oven | 450–500°F | 230–260°C | 8 – 9 |
| Broil / grill | 500–550°F | 260–290°C | 10 |
USDA safe minimum internal temperatures. Use a food thermometer.
Body Temperature and Fever Reference
| Condition | °F | °C | Action |
|---|---|---|---|
| Hypothermia | < 95°F | < 35°C | Emergency — seek medical help |
| Normal body temp | 97.7–99.5°F | 36.5–37.5°C | Healthy range |
| Low-grade fever | 99.5–100.9°F | 37.5–38.3°C | Monitor, rest, fluids |
| Fever | 101–103°F | 38.3–39.4°C | OTC medication, monitor |
| High fever | > 103°F | > 39.4°C | Seek medical attention |
| Hyperthermia | > 104°F | > 40°C | Emergency — call 911 |
Normal body temperature varies by person, time of day, and measurement site. The traditional 98.6°F (37°C) average dates from an 1868 study; modern research suggests 97.9°F (36.6°C) is more accurate (Protsiv et al., 2020, eLife).
Understanding Fahrenheit and Celsius
Fahrenheit was developed by Daniel Gabriel Fahrenheit in 1724. He set 0°F as the temperature of a brine solution and 96°F as approximately human body temperature. Celsius was proposed by Anders Celsius in 1742, originally with 0° as boiling and 100° as freezing (later inverted). Today, Celsius is tied to the Kelvin scale: 0°C = 273.15 K (water's freezing point) and 100°C = 373.15 K (water's boiling point at 1 atm).
The US is the only major country that uses Fahrenheit as its primary temperature scale. Every other nation uses Celsius for weather, cooking, and science. The scales intersect at exactly -40° — the one temperature that reads the same on both.
Mental Math Shortcuts
°F to °C (approximate): Subtract 30, then divide by 2. Example: 80°F → (80−30)/2 = 25°C (actual: 26.7°C). Good enough for weather.
°C to °F (approximate): Double and add 30. Example: 20°C → (20×2)+30 = 70°F (actual: 68°F). Close enough for daily use.
Key anchor points to memorize: 0°C = 32°F (freezing), 10°C = 50°F (cool), 20°C = 68°F (room temp), 30°C = 86°F (hot), 37°C = 98.6°F (body), 100°C = 212°F (boiling).
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