Conversion Calculator
Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin instantly with step-by-step conversion formulas.
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The guide, formula, examples, and FAQ are available below.
How to Use This Calculator
Enter Temperature Value
Type your temperature value into the input field. For example: e.g., 100.
Select From
Choose the appropriate option from the "From" dropdown. Options include: Celsius (°C), Fahrenheit (°F), Kelvin (K).
Select To
Choose the appropriate option from the "To" dropdown. Options include: Celsius (°C), Fahrenheit (°F), Kelvin (K).
View Your Result
The result appears beside the calculator with the main answer and a detailed calculation breakdown.
Adjust and Explore
Change any input value and calculate again. Use the copy and share controls to save or send your result.
On this page
Formula
Temperature conversions use linear formulas. Celsius and Fahrenheit differ in both scale and offset, while Kelvin uses the same scale as Celsius but starts at absolute zero (-273.15 °C).
Unit conversion note
Conversion calculators use standard metric, imperial, and US customary relationships.
Cooking and regional units may vary, so check the unit system shown on the calculator before relying on a result.
Source and review references
Last reviewed by the Calculator Trust Editorial Team. To report an issue, email contact [at] calculatortrust.com.
Common Examples
Understanding the Concept
Temperature conversion is one of the most common unit conversions in daily life, science, and engineering. Whether you are reading a weather forecast from another country, adjusting a recipe, or working on a physics problem, being able to quickly convert between Celsius, Fahrenheit, and Kelvin is an essential skill. This converter handles all three scales with step-by-step explanations.
The Three Temperature Scales
- Celsius (°C): Used by most of the world for everyday temperature measurements. Water freezes at 0 °C and boils at 100 °C at standard atmospheric pressure. Developed by Anders Celsius in 1742.
- Fahrenheit (°F): Primarily used in the United States and a few other countries. Water freezes at 32 °F and boils at 212 °F. Developed by Daniel Gabriel Fahrenheit in 1724.
- Kelvin (K): The SI unit of temperature used in science. It starts at absolute zero (the coldest possible temperature) and uses the same increment size as Celsius. Water freezes at 273.15 K and boils at 373.15 K.
Conversion Formulas
The key formulas for temperature conversion are:
- Celsius to Fahrenheit: °F = °C x 9/5 + 32
- Fahrenheit to Celsius: °C = (°F - 32) x 5/9
- Celsius to Kelvin: K = °C + 273.15
- Kelvin to Celsius: °C = K - 273.15
- Fahrenheit to Kelvin: K = (°F - 32) x 5/9 + 273.15
A useful quick reference: -40° is the same in both Celsius and Fahrenheit. Room temperature is about 20-22 °C or 68-72 °F. Normal body temperature is about 37 °C or 98.6 °F.
Common Temperature References
Here are some commonly referenced temperatures across all three scales:
- Absolute zero: -273.15 °C / -459.67 °F / 0 K
- Water freezes: 0 °C / 32 °F / 273.15 K
- Room temperature: ~20 °C / ~68 °F / ~293.15 K
- Body temperature: 37 °C / 98.6 °F / 310.15 K
- Water boils: 100 °C / 212 °F / 373.15 K
Frequently Asked Questions
What is the formula to convert Celsius to Fahrenheit?
What is absolute zero?
Why does the United States use Fahrenheit?
At what temperature are Celsius and Fahrenheit equal?
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Written and reviewed by Calculator Trust Editorial Team
Our calculators are built using verified formulas from academic, government, and scientific sources. Content is fact-checked and reviewed for accuracy.