Convert between Celsius, Fahrenheit, and Kelvin temperature scales with precision. Essential tool for science, cooking, weather, and international communication.
Last updated: March 2026 | By Patchworkr Team
Temperature conversion is the process of transforming a temperature measurement from one scale to another. The three most commonly used temperature scales are Celsius (°C), Fahrenheit (°F), and Kelvin (K), each with different reference points and uses.
Celsius is the standard metric scale, used worldwide for everyday temperature measurement. It's based on the freezing point (0°C) and boiling point (100°C) of water at standard atmospheric pressure.
Fahrenheit is primarily used in the United States and a few other countries. Water freezes at 32°F and boils at 212°F. This scale was designed to avoid negative numbers in typical weather conditions.
Kelvin is the SI base unit of temperature, used primarily in scientific contexts. It starts at absolute zero (0 K = -273.15°C), the theoretical lowest possible temperature where all molecular motion stops.
Multiply the Celsius temperature by 1.8 (or 9/5), then add 32.
Subtract 32 from the Fahrenheit temperature, then multiply by 5/9 (or 0.5556).
Simply add 273.15 to the Celsius temperature.
Subtract 273.15 from the Kelvin temperature.
Different scales were developed for different purposes. Celsius is metric and water-based. Fahrenheit was designed for everyday weather (avoiding negatives). Kelvin is absolute and used in science because it starts at absolute zero.
Absolute zero (0 K = -273.15°C = -459.67°F) is the theoretical lowest possible temperature where all molecular motion stops. Nothing can be cooled below this temperature.
Only the United States, Bahamas, Belize, Cayman Islands, and Palau still use Fahrenheit for everyday temperature. The rest of the world uses Celsius.
No, Kelvin cannot be negative because it starts at absolute zero, the coldest possible temperature. This makes Kelvin ideal for scientific calculations involving temperature ratios.
A quick mental estimate: double the Celsius temperature and add 30. For example, 20°C ≈ (20 × 2) + 30 = 70°F. The actual value is 68°F, so it's close enough for everyday use.
The two scales intersect at -40°. That is, -40°C = -40°F. This is the only point where both scales show the same numerical value.
Normal human body temperature is about 37°C. When converted to Fahrenheit (37 × 9/5 + 32), this equals 98.6°F. However, modern studies show normal body temperature varies between 97°F and 99°F.
For everyday use, rounding to whole numbers is fine. For cooking, round to one decimal place. For scientific work, use at least two decimal places or more depending on your precision requirements.
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