Temperature Converter

Convert Between Celsius, Fahrenheit & Kelvin

Celsius
°C
Fahrenheit
°F
Kelvin
K

Conversion Formulas:

°F = (°C × 9/5) + 32
°C = (°F - 32) × 5/9
K = °C + 273.15
°C = K - 273.15
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

Understanding Temperature Scales

Temperature is a measure of the average kinetic energy of particles in a substance. Three main scales are used worldwide: Celsius (used by most countries), Fahrenheit (primarily used in the United States), and Kelvin (used in scientific contexts). Each scale has its own reference points and applications.

The Celsius scale, also called centigrade, sets water's freezing point at 0° and boiling point at 100° at standard atmospheric pressure. This makes it intuitive for everyday use and scientific calculations. The Fahrenheit scale sets water's freezing at 32° and boiling at 212°, providing finer gradations for weather temperatures commonly experienced in temperate climates.

The Kelvin Scale

Kelvin is the SI base unit for temperature and is essential in physics and chemistry. It starts at absolute zero (0 K), the theoretical temperature where all molecular motion ceases. Unlike Celsius and Fahrenheit, Kelvin uses no degree symbol and has no negative values. Scientists prefer Kelvin because many physical laws work more simply when using an absolute temperature scale.

Understanding temperature conversions is crucial for international communication, scientific research, cooking with international recipes, and understanding weather forecasts from different countries. This converter handles all conversions instantly, helping you navigate between these different scales effortlessly.

Frequently Asked Questions

How do you convert Celsius to Fahrenheit?
To convert Celsius to Fahrenheit, use the formula: °F = (°C × 9/5) + 32. For example, 20°C = (20 × 9/5) + 32 = 68°F. Multiply the Celsius temperature by 1.8 (or 9/5), then add 32.
How do you convert Fahrenheit to Celsius?
To convert Fahrenheit to Celsius, use the formula: °C = (°F - 32) × 5/9. For example, 68°F = (68 - 32) × 5/9 = 20°C. Subtract 32 from the Fahrenheit temperature, then multiply by 5/9 (or 0.5556).
What is Kelvin and how is it used?
Kelvin is the SI unit of temperature used primarily in science. It starts at absolute zero (0 K = -273.15°C), the theoretical coldest possible temperature. Unlike Celsius and Fahrenheit, Kelvin has no negative values. Convert Celsius to Kelvin by adding 273.15: K = °C + 273.15.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at -40 degrees. This is the only temperature where -40°C = -40°F. This intersection point occurs because of the mathematical relationship between the two scales.
Why does the US use Fahrenheit while most countries use Celsius?
The United States adopted Fahrenheit before the metric system became widespread. Most other countries switched to Celsius as part of metrication in the 20th century. Celsius is based on water's freezing (0°C) and boiling (100°C) points, making it more intuitive for scientific use.