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Temperature Converter Tool

Enter a value and pick a unit (°C, °F, or K) to convert between Celsius, Fahrenheit, and Kelvin at the same time. Includes an absolute zero check and conversion formulas, all processed in your browser.

Last updated: 2026/10/16 Calculator Feedback & bug reports
Enter temperature
Enter a number to see the conversion results.
The entered temperature is below absolute zero (-273.15°C / -459.67°F / 0K), which cannot physically exist. Please check your input.

How to Use

1

Enter a temperature value

Type the temperature you want to convert. Negative numbers and decimals are supported.

2

Choose the input unit

Select whether your value is in Celsius (°C), Fahrenheit (°F), or Kelvin (K).

3

View all three units

The other two units are converted automatically and all three values are shown in real time.

4

Copy if needed

Use the "Copy Results" button to copy all three converted values to your clipboard at once.

Conversion Formulas

  • Celsius to Fahrenheit: °F = °C × 9 / 5 + 32
  • Fahrenheit to Celsius: °C = (°F − 32) × 5 / 9
  • Celsius to Kelvin: K = °C + 273.15
  • Kelvin to Celsius: °C = K − 273.15
  • Fahrenheit to Kelvin: K = (°F − 32) × 5 / 9 + 273.15

Temperature Conversion Chart

A quick reference table of common temperatures in Celsius, Fahrenheit, and Kelvin for cooking, weather, and science.

Celsius °C Fahrenheit °F Kelvin K Reference
-273.15-459.670Absolute zero
032273.15Water freezes
2577298.15Comfortable room
3798.6310.15Body temperature
100212373.15Water boils (1 atm)
180356453.15Moderate oven

About the Temperature Converter

A web tool that converts between the three temperature units: Celsius (°C), Fahrenheit (°F), and Kelvin (K). Just enter a value and pick a unit, and it instantly converts to the other two units and displays all three at once. Values below absolute zero are flagged, and the conversion formulas are shown. All calculations run entirely in your browser, and your input is never sent to a server.

Features

  • Real-time ConversionConverts to all three units instantly as you type, with no waiting.
  • All Three Units at OnceCelsius, Fahrenheit, and Kelvin side by side, with the input unit clearly marked.
  • Absolute Zero CheckWarns you when you enter a temperature below absolute zero that cannot exist.
  • Privacy ProtectedAll processing happens in your browser. Your input is never sent to servers.

Use Cases

  • Read overseas weather forecasts (°F) in Celsius
  • Convert oven temperatures (°F) in foreign recipes to °C
  • Convert to Kelvin for science and physics homework
  • Convert temperature specs in product manuals
  • Get a feel for air and body temperature units

FAQ

What is the difference between Celsius, Fahrenheit, and Kelvin?
Celsius (°C) sets water freezing at 0 and boiling at 100 and is used in most countries. Fahrenheit (°F), used mainly in the US, sets water freezing at 32 and boiling at 212. Kelvin (K) is a scientific unit starting at absolute zero, with the same step size as Celsius.
What is the formula to convert Celsius to Fahrenheit?
°F = °C × 9 ÷ 5 + 32. For example, 25°C is 25 × 9 ÷ 5 + 32 = 77°F. To go the other way, use °C = (°F − 32) × 5 ÷ 9.
How is Kelvin calculated?
Kelvin equals Celsius plus 273.15 (K = °C + 273.15). For example, 0°C is 273.15K and 25°C is 298.15K. Kelvin has no negative values; 0K (absolute zero) is the theoretical minimum temperature.
What happens if I enter a value below absolute zero?
The conversion is still performed, but because temperatures below absolute zero (-273.15°C / -459.67°F / 0K) cannot physically exist, a warning is shown to help you catch input mistakes.
Can I convert decimal and negative temperatures?
Yes. Decimal values and negative temperatures are fully supported. Results are rounded to a readable number of decimal places.
Is my entered temperature sent to a server?
No. All conversion is done locally in your browser with JavaScript. Your input is never sent to or stored on any server, so you can use it with confidence.

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Related Guides

Celsius vs Fahrenheit vs Kelvin: Temperature Conversion Made Simple Understand the temperature units Celsius (C), Fahrenheit (F), and Kelvin (K) from the ground up: how they differ, the Celsius-Fahrenheit conversion formulas, Kelvin and absolute zero, the freezing and boiling points of water, how to read overseas weather forecasts, and easy tricks to convert in your head.