Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin instantly. See all three temperature scales side by side with formulas and a common temperature reference table.
Enter a temperature value, select your scale, and see conversions to all three temperature units simultaneously.
Conversions
Formulas Used
Common Temperature Reference
| Description | °C | °F | K |
|---|---|---|---|
| Absolute Zero | −273.15 | −459.67 | 0 |
| Water Freezes | 0 | 32 | 273.15 |
| Room Temperature | 20–22 | 68–72 | 293–295 |
| Human Body | 37 | 98.6 | 310.15 |
| Water Boils | 100 | 212 | 373.15 |
How It Works
Unlike length or weight, temperature scales are not related by simple ratios. Each scale has a different zero point and degree size, so conversion requires both multiplication and addition.
Celsius (°C) sets 0° at the freezing point of water and 100° at its boiling point at standard atmospheric pressure. It is used worldwide for everyday temperatures and in science.
Fahrenheit (°F) sets 32° at the freezing point of water and 212° at its boiling point. The scale was originally calibrated using a brine mixture for 0°F. It is primarily used in the United States.
Kelvin (K) is the SI unit of thermodynamic temperature. It uses the same degree size as Celsius but starts at absolute zero (0 K = −273.15°C), the theoretical lowest temperature where all molecular motion ceases.
Core conversion formulas:
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
- °C = K − 273.15
Frequently Asked Questions
Multiply the Celsius value by 9/5 (or 1.8) and add 32. For a rough estimate, double the Celsius value and add 30. For example, 25°C ≈ (25 × 2) + 30 = 80°F (exact: 77°F).
Absolute zero is 0 Kelvin (−273.15°C or −459.67°F). It is the theoretical lowest possible temperature, where particles have minimal kinetic energy. It has never been fully reached in a laboratory.
The Fahrenheit scale was developed by Daniel Gabriel Fahrenheit in 1724 and was widely adopted in English-speaking countries. While most nations switched to Celsius with metrication, the US retained Fahrenheit for everyday use due to custom and the cost of conversion.
Celsius and Fahrenheit are equal at −40 degrees. Setting °C = °F in the formula °F = °C × 9/5 + 32 gives °C = °C × 9/5 + 32, which solves to °C = −40.
Related Tools
Length Converter
Convert between metric and imperial length units including millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles.
ConvertersWeight Converter
Convert between metric and imperial weight units including grams, kilograms, ounces, pounds, stone, and tons.
ConvertersSpeed Converter
Convert between speed units including km/h, mph, knots, m/s, ft/s, and Mach number.
Converters