Temperature Converter

Convert between Celsius (°C), Fahrenheit (°F), and Kelvin (K) instantly. Accurately convert temperatures for cooking, weather, science, and travel. Free temperature converter.

How to Use

  1. Enter the temperature value

    Type the temperature value you want to convert.

  2. Select the units

    Choose the source scale (e.g., °C) and the target scale (e.g., °F).

  3. View the result

    Click Convert to see the converted temperature value.

What is temperature unit conversion?

Temperature conversion is the act of expressing the same thermal state on different scales. Even for the same temperature, Korea and Europe use Celsius (°C), the United States uses Fahrenheit (°F), and scientific fields use Kelvin (K), which is why conversion is needed.

The three units have different reference points.

  • Celsius: water freezes at 0°C and boils at 100°C
  • Fahrenheit: freezes at 32°F and boils at 212°F (the intervals are 1.8 times finer)
  • Kelvin: based on absolute zero (0 K = -273.15°C), where molecular motion stops; the interval size is identical to Celsius

Accurate conversion is essential when reading oven temperatures in foreign recipes, U.S. weather forecasts, material data in research papers, or when handling medical, meteorological, and engineering documents.

Conversion Formula

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

Example 1. 25°C to Fahrenheit: 25 × 9/5 + 32 = 45 + 32 = 77°F

Example 2. 98.6°F to Celsius: (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37°C

Fahrenheit and Kelvin have no direct formula, so the conversion goes through Celsius. The coefficient 9/5 (=1.8) reflects that the Fahrenheit scale is 1.8 times finer than Celsius, and 32 corrects for the difference in freezing points.

Frequently Asked Questions

What is the formula to convert Celsius to Fahrenheit?
Fahrenheit (°F) = Celsius (°C) × 9/5 + 32. For example, 100°C is 212°F, and 0°C is 32°F. To convert Fahrenheit back to Celsius, use (°F − 32) × 5/9.
What is Kelvin (K)?
Kelvin is the base unit of temperature in the International System of Units (SI). It is referenced to absolute zero (0 K = -273.15°C), and since its interval size matches Celsius, you simply add 273.15 to Celsius to get Kelvin. It is written as 'K' without the degree (°) symbol.
What is absolute zero?
Absolute zero is the lowest temperature theoretically attainable: 0 K = -273.15°C = -459.67°F. At this temperature, the thermal motion of molecules stops, and by the laws of thermodynamics it can never be perfectly reached in practice.
What is a body temperature of 36.5°C in Fahrenheit?
36.5 × 9/5 + 32 = 97.7°F. The normal body temperature range is 97.8–99.1°F (36.5–37.3°C), and the fever threshold of 38°C corresponds to 100.4°F.
Is there a temperature where Celsius and Fahrenheit are equal?
Yes, -40°C = -40°F is the only point where the two scales match exactly. This result comes from setting the two values equal in °C = (°F − 32) × 5/9 and solving.
How do I match temperatures in foreign oven recipes?
U.S. recipes use Fahrenheit, so find Celsius with (°F − 32) × 5/9. For example, 350°F is about 177°C, 400°F is about 204°C, and 450°F is about 232°C. Note that gas mark (GM) notation is a separate system.
Can I convert Fahrenheit directly to Kelvin?
The direct formula is K = (°F − 32) × 5/9 + 273.15. It gives the same result as the two-step approach of converting Fahrenheit to Celsius first and then adding 273.15. For example, 32°F is 273.15 K.
Is there a quick way to estimate Celsius to Fahrenheit mentally?
Instead of the exact formula, you can approximate with '°C × 2 + 30'. 20°C is about 70°F (actually 68°F), so the error is small within everyday temperature ranges. If you need a precise value, use the 9/5 coefficient as is.
2026 international standards

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