Temperature Converter
Enter a value in any field and all other scales update instantly.
Conversion Formulas
- F = C × 9/5 + 32
- C = (F − 32) × 5/9
- K = C + 273.15
- C = K − 273.15
Common Reference Points
| Description | °C | °F | K |
|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 |
| Water Freezes | 0 | 32 | 273.15 |
| Room Temperature | 20 | 68 | 293.15 |
| Body Temperature | 37 | 98.6 | 310.15 |
| Water Boils | 100 | 212 | 373.15 |
How Temperature Scales Work
Temperature measures the average kinetic energy of particles in a substance. Three scales are commonly used worldwide. Celsius, developed by Anders Celsius in 1742, sets water's freezing point at 0 degrees and boiling point at 100 degrees under standard atmospheric pressure. It is the standard in most countries and in scientific contexts alongside Kelvin.
Fahrenheit, proposed by Daniel Gabriel Fahrenheit in 1724, sets water's freezing point at 32 degrees and boiling point at 212 degrees. It divides the range between these two points into 180 equal intervals. The Fahrenheit scale is primarily used in the United States, its territories, and a few other countries. The conversion formula F = C x 9/5 + 32 reflects the different zero points and degree sizes of the two scales.
Kelvin is the SI base unit of temperature, used extensively in physics and chemistry. It uses the same degree size as Celsius but starts at absolute zero, the theoretical point where all thermal motion stops. This means Kelvin never has negative values, making it ideal for scientific calculations involving thermodynamics, gas laws, and radiation. Converting between Celsius and Kelvin is straightforward: simply add or subtract 273.15.
Frequently Asked Questions
How do you convert Celsius to Fahrenheit?
To convert Celsius to Fahrenheit, multiply the Celsius temperature by 9/5 (or 1.8) and then add 32. The formula is: F = C x 9/5 + 32. For example, 100 degrees Celsius equals 212 degrees Fahrenheit.
What is absolute zero?
Absolute zero is the lowest theoretically possible temperature, where all molecular motion ceases. It is 0 Kelvin, which equals -273.15 degrees Celsius or -459.67 degrees Fahrenheit. No object can actually reach absolute zero, though scientists have come within fractions of a degree.
At what temperature are Celsius and Fahrenheit the same?
Celsius and Fahrenheit are equal at -40 degrees. At this temperature, -40 degrees C equals exactly -40 degrees F. This can be verified using the formula: F = (-40 x 9/5) + 32 = -72 + 32 = -40.
Why does the US use Fahrenheit instead of Celsius?
The US adopted Fahrenheit because it was the dominant scale when the country was founded. Daniel Fahrenheit developed it in 1724, predating Anders Celsius's scale by 18 years. While most countries switched to Celsius as part of metrication, the US never fully adopted the metric system for everyday use.