Formula – How to convert Fahrenheit (°F) to Celsius (°C)
Formula 1: Easy to remember
((°F -32) x 5)÷9
- Step 1: Subtract 32 from the temperature in Fahrenheit
- Step 2: Multiply that number by 5
- Step 3: Divide that number by 9
Example
Find 60°F in Celsius:
- Step 1: Subtract 32 from the °F: 60 – 32 = 28
- Step 2: Multiply that number by 5: 28 x 5 = 140
- Step 3: Divide that number by 9: 140 ÷ 9 = 15.56°C
Formula 2: Quicker
(°F – 32) ÷ 1.8
- Step 1: Subtract 32 from the temperature in Fahrenheit
- Step 2: Divide that number by 1.8
Example
Find 70°F in Celsius:
- Step 1: Subtract 32 from the temperature in Fahrenheit: 70 – 32 = 38
- Step 2: Divide that number by 1.8: 38 ÷ 1.8 = 21.11°C
What is the difference between Celsius and Fahrenheit?
Celsius and Fahrenheit are two temperature scales.
Celsius is benchmarked from the freezing point of water (0°C) and the boiling point of water (100°C).
Fahrenheit’s origins are not certain, however it is believed that 0°F was the freezing point of equal parts ice, water, and salt. 100°F was about the body temperature of a person. Today, Fahrenheit is benchmarked from the freezing point of water (32°F) and the boiling point of water (212°F).
Who uses Celsius and Fahrenheit?
Celsius is a “standard unit” and is commonly used worldwide.
Fahrenheit is used in the United States as well as some regions of the Pacific and the Caribbean.
What are other common temperature scales?
Kelvin and Rankine are the two other temperature scales. They are benchmarked off absolute 0 (the coldest temperature possible).
Kelvin (°K) increases at the same rate as the Celsius scale, but is offset by 273.15° from Celsius. Absolute 0 is -273.15°C, and 0K.
Rankine (°R) increases at the same rate as the Fahrenheit scale, but is offset by 459.67° from Fahrenheit. Absolute 0 is -459.67°F, and 0°R.
Sources and more resources
- Wikipedia – Celsius, Fahrenheit, Conversion of Units of Temperature, and Scale of Temperature – An introduction to both temperature scales and the concept of a temperature scale.
- ISO 80000-5:2019 – The ISO standard defining temperature.
- NIST Physical Measurement Laboratory – SI Units – Temperature – Details on temperature by the National Institute of Standards and Technology.
- Prof. James Schombert, Department of Physics, University of Oregon – Temperature Scale (Glossary) – An overview of the 3 common temperature scales of today, Celsius, Fahrenheit, and Kelvin.