How do I convert Fahrenheit to Celsius?

Formula: °C = (°F − 32) × 5/9. Examples: 98.6°F (body temp) = (98.6−32)×5/9 = 66.6×0.556 = 37°C. 32°F (freezing) = 0°C. 212°F (boiling) = 100°C. 72°F (room temp) ≈ 22.2°C. Quick estimate: subtract 30 and halve → 72°F: (72−30)÷2 = 21°C (exact is 22.2, but close enough for everyday use).

What is 100 degrees Fahrenheit in Celsius?

(100 − 32) × 5/9 = 68 × 0.5556 = 37.8°C. 100°F is approximately body temperature for a person with a mild fever (normal body temp is 98.6°F = 37.0°C).

At what temperature are Fahrenheit and Celsius equal?

°F and °C are equal at −40°. Both scales converge at −40°, because −40°C = (−40 × 9/5) + 32 = −72 + 32 = −40°F.

Why does the US use Fahrenheit while most countries use Celsius?

The Fahrenheit scale was proposed by Daniel Fahrenheit in 1724 and was widely adopted in English-speaking countries. Most of the world switched to Celsius (proposed by Anders Celsius in 1742) as part of metric system adoption in the 19th–20th centuries. The US, Myanmar, and the Cayman Islands are the only countries that still use Fahrenheit as the primary temperature scale in everyday life.

Fahrenheit to Celsius (°F to °C) Converter

Also try: °C to °F | °C to K

Fahrenheit to Celsius — Formula & Reference

The Fahrenheit scale (°F) is primarily used in the United States for everyday temperature measurement. The Celsius scale (°C) is the international standard for scientific and most everyday usage.

Formula

              °C = (°F − 32) × 5/9
            

Key Reference Temperatures

Fahrenheit (°F)	Celsius (°C)	Reference
32 °F	0 °C	Freezing point of water
68 °F	20 °C	Room temperature
98.6 °F	37 °C	Normal body temperature
212 °F	100 °C	Boiling point of water

Related Converters

°C → °F °C → K K → °C KG → LBS KPH → MPH L → gal

Fahrenheit to Celsius: Formula and Quick Methods

The exact formula is °C = (°F − 32) × 5/9. Subtract 32 first (to shift the zero point), then multiply by 5/9 (to adjust the scale). For mental estimates: subtract 30 and halve the result. 68°F → (68−30)/2 = 19°C (true answer: 20°C, close enough). Another shortcut for weather: 60°F ≈ cool (16°C), 70°F ≈ comfortable (21°C), 80°F ≈ warm (27°C), 90°F ≈ hot (32°C), 100°F ≈ very hot (38°C).

The two scales intersect at −40°: −40°F = −40°C. The Fahrenheit scale was defined with 0°F as the coldest brine mixture and 96°F as human body temperature. Water's 32°F freeze and 212°F boil points came later. The US, Bahamas, Cayman Islands, and Palau still use Fahrenheit; everywhere else uses Celsius for everyday weather and temperature.

Fahrenheit to Celsius Key Points

°F	°C	Context
-40	−40	Scales are equal
32	0	Water freezes
50	10	Chilly day
68	20	Comfortable room
77	25	Warm room
98.6	37	Body temperature
212	100	Water boils

The Fahrenheit to Celsius Formula and Its History

Water freezes at 32°F (0°C) and boils at 212°F (100°C) — an 180-degree Fahrenheit range mapped to a 100-degree Celsius range, giving the conversion formula C = (F − 32) × 5/9. Daniel Gabriel Fahrenheit developed his scale around 1724, setting 0° at the coldest brine temperature he could achieve and calibrating upper points against body temperature. Anders Celsius introduced the centigrade scale in 1742. Today, the United States uses Fahrenheit for everyday temperatures while virtually every other country and all scientific disciplines use Celsius. A useful mental shortcut: subtract 30 and halve the result for a rough Celsius estimate (±3° accuracy for the range 0°F to 100°F). For exact conversions, always use the precise formula, especially in medical or industrial contexts where temperature accuracy is critical.

Fahrenheit to Celsius Reference Table

°F	°C	Reference
32	0	Water freezes
72	22.2	Comfortable room
98.6	37	Body temperature
212	100	Water boils
350	176.7	Moderate oven
450	232.2	Hot oven