Convert temperature between Fahrenheit and Celsius with step-by-step solutions and conversion formulas
| Description | Fahrenheit (°F) | Celsius (°C) |
|---|---|---|
| Absolute Zero | −459.67 °F | −273.15 °C |
| Freezing Point of Water | 32 °F | 0 °C |
| Room Temperature | 68 °F | 20 °C |
| Normal Body Temperature | 98.6 °F | 37 °C |
| Boiling Point of Water | 212 °F | 100 °C |
Temperature conversion between Fahrenheit and Celsius is essential in daily life, science, cooking, travel, and many other areas. Understanding how these temperature scales relate to each other helps you navigate between different measurement systems used around the world.
Fahrenheit to Celsius
°C = (°F − 32) × 5/9
or
°C = (°F − 32) ÷ 1.8
Celsius to Fahrenheit
°F = (°C × 9/5) + 32
or
°F = (°C × 1.8) + 32
The Fahrenheit and Celsius scales have fascinating historical backgrounds that explain their seemingly arbitrary reference points.
Created by Daniel Gabriel Fahrenheit in 1724, this scale was based on three reference points:
Primarily used in the United States, Bahamas, Belize, Cayman Islands, and Palau.
Developed by Anders Celsius in 1742, this scale is based on the properties of water:
Used by most countries worldwide and is the standard in scientific contexts. Also called centigrade because of the 100-degree interval between freezing and boiling points.
Given: 77 °F
Formula: °C = (°F − 32) × 5/9
°C = (77 − 32) × 5/9
°C = 45 × 5/9
°C = 225/9
°C = 25
Therefore, 77 °F is equal to 25 °C, which is a pleasant room temperature.
Given: 5 °F
Formula: °C = (°F − 32) × 5/9
°C = (5 − 32) × 5/9
°C = −27 × 5/9
°C = −135/9
°C = −15
Therefore, 5 °F equals −15 °C, which is well below freezing.
Given: 98.6 °F
Formula: °C = (°F − 32) × 5/9
°C = (98.6 − 32) × 5/9
°C = 66.6 × 5/9
°C = 333/9
°C = 37
Normal human body temperature is 98.6 °F or 37 °C.
Given: 212 °F
Formula: °C = (°F − 32) × 5/9
°C = (212 − 32) × 5/9
°C = 180 × 5/9
°C = 900/9
°C = 100
Water boils at 212 °F or 100 °C at standard atmospheric pressure.
Recipe temperatures often need conversion between systems. Oven temperatures, meat doneness, and candy-making stages all rely on accurate temperature measurements.
Weather forecasts use different scales in different countries. Understanding both scales helps you prepare appropriate clothing and activities when traveling.
Body temperature monitoring for fever detection requires knowing both scales, as medical equipment may use either system depending on the country.
While Celsius (and Kelvin) is standard in scientific work, some engineering applications still use Fahrenheit, requiring conversion between systems.
Example: 68 °F → (68 - 30) ÷ 2 = 19 °C (actual: 20 °C)
Example: 20 °C → (20 × 2) + 30 = 70 °F (actual: 68 °F)
The conversion formulas derive from the relationship between the two scales:
Understanding which countries use which scale helps in international communication:
Most countries worldwide use Celsius, including:
Only a few countries primarily use Fahrenheit:
Even in these countries, scientific contexts typically use Celsius.
While Celsius and Fahrenheit are most common in daily life, scientists often use Kelvin, which starts at absolute zero (the coldest possible temperature).
Celsius to Kelvin: K = °C + 273.15
Fahrenheit to Kelvin: K = (°F + 459.67) × 5/9
Note: Kelvin doesn't use the degree symbol (°).
The exact formula is °C = (°F − 32) × 5/9. For a quick mental estimate, subtract 30 and divide by 2. For example, 70 °F → (70 - 30) ÷ 2 = 20 °C (actual answer: 21.1 °C). This approximation is useful for everyday situations where precision isn't critical.
The United States adopted the Fahrenheit scale early in its history and has continued using it due to tradition and the cost of switching all infrastructure, education materials, and consumer products. However, American scientists and many industries do use Celsius and the metric system.
The two scales intersect at −40 degrees. That is, −40 °F = −40 °C. This can be proven algebraically by setting °F = °C in the conversion formula and solving for the temperature value.
Yes! At 11.428571 °C, the Fahrenheit reading is 52.571429 °F. These aren't exact opposites, but the closest relationship is that certain pairs of values have interesting mathematical relationships. However, there's no simple "opposite" relationship between the scales.
Both scales are equally accurate—they're just different ways of measuring the same physical property. Neither is inherently more precise than the other. However, Celsius has advantages in scientific work because it's based on the properties of water and aligns with the Kelvin scale (just add 273.15).
The value 98.6 °F comes from converting 37 °C to Fahrenheit. Carl Wunderlich, a German physician, determined that normal body temperature was 37 °C in the 1860s. When converted to Fahrenheit, 37 °C × 9/5 + 32 = 98.6 °F. The Celsius version is the round number; Fahrenheit just reflects the conversion.
Use the standard conversion formula, but be aware that most ovens have temperature variations of ±25 °F anyway. Common conversions: 350 °F = 175 °C, 375 °F = 190 °C, 400 °F = 200 °C, 425 °F = 220 °C, 450 °F = 230 °C. Many modern recipes list both temperatures.
Yes! The conversion formulas work perfectly for negative temperatures. For example, −40 °F = −40 °C, and 0 °F = −17.78 °C. Cold temperatures often need conversion for winter weather forecasts and frozen storage requirements.