Temperature Unit Conversion Guide
Three temperature scales are in widespread use: Celsius (°C) — the international standard for everyday use; Fahrenheit (°F) — used in the United States for weather and cooking; and Kelvin (K) — the absolute scale used in science. Understanding the relationships between scales is important for cooking, weather, science, and international communication.
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Formula
Temperature Converter
Convert temperature between Celsius, Fahrenheit, and Kelvin instantly.
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Worked Example
Given:
Related Calculators
FAQs
Why does the US use Fahrenheit instead of Celsius?
The Fahrenheit scale was developed by Daniel Fahrenheit in 1724 and was the standard in English-speaking countries. Most countries switched to Celsius when metrication occurred in the 1960s–80s. The US retained Fahrenheit for everyday use, though science and medicine use Celsius.
What is absolute zero?
Absolute zero (0 K = -273.15°C = -459.67°F) is the lowest possible temperature — the point at which all molecular motion ceases. It is physically impossible to reach absolute zero but scientists have cooled matter to within nanokelvins of it. The Kelvin scale starts at absolute zero, making it convenient for thermodynamic calculations.
At what temperature are Celsius and Fahrenheit the same?
Celsius and Fahrenheit are equal at exactly -40°. At this point, -40°C = -40°F. This can be verified by setting the conversion formula equal: C = (F-32) × 5/9, and solving for C = F gives -40.