Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales.
What Is the Temperature Converter?
The Temperature Converter converts between Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R) temperature scales. It handles all four common temperature units used in science, engineering, cooking, and everyday life, with instant real-time conversion.
Formula
How to Use
Enter a temperature value in any of the four scales: Celsius, Fahrenheit, Kelvin, or Rankine. The converter instantly displays the equivalent temperature in all other scales. Reference points (water freezing/boiling, body temperature, room temperature) are shown for context.
Example Calculation
Body temperature 37°C: = (37×9/5)+32 = 98.6°F = 37+273.15 = 310.15 K = 98.6+459.67 = 558.27°R. Absolute zero: 0 K = −273.15°C = −459.67°F = 0°R.
Understanding Temperature Converter
Temperature scales differ in their zero point and degree size. The Celsius scale anchors 0° to the freezing point of water and 100° to boiling, making it intuitive for everyday use. Fahrenheit uses 32° for freezing and 212° for boiling — finer gradations for weather but less convenient for science. Kelvin starts at absolute zero with Celsius-sized degrees, making it the SI unit for thermodynamic temperature.
The conversion between Celsius and Fahrenheit involves both scaling (ratio 5:9) and offset (32°F at 0°C). This non-linear relationship means simple mental math is difficult. Useful approximations: double the Celsius temperature and add 30 gives a rough Fahrenheit value. An exact mental trick: −40° is the same in both scales, and room temperature is about 20°C / 68°F.
Temperature conversion is needed in cooking (oven temperatures between European and US recipes), meteorology (international weather data), science (experimental temperatures in Kelvin), materials science (melting points and phase transitions), and chemistry (reaction temperatures and thermodynamic calculations). The Kelvin scale is essential for using the ideal gas law and other thermodynamic equations.
Frequently Asked Questions
Why does the US use Fahrenheit while most countries use Celsius?
Fahrenheit was the dominant scale in the English-speaking world until the 20th century. Most countries metricated in the 1960s-80s and switched to Celsius. The US, Belize, Cayman Islands, and a few other places still use Fahrenheit daily.
What is absolute zero?
Absolute zero (0 K = −273.15°C = −459.67°F) is the theoretical minimum temperature where all thermal motion stops. It is physically unattainable but can be approached to within nanokelvins in laboratory settings.
What is the Rankine scale?
Rankine (°R) is an absolute temperature scale using Fahrenheit degree increments. 0°R = absolute zero, and 459.67°R = 0°F. It is used in some US engineering thermodynamics calculations.
What temperature does water freeze and boil?
Water freezes at 0°C (32°F, 273.15 K) and boils at 100°C (212°F, 373.15 K) at standard atmospheric pressure (1 atm). At higher altitudes (lower pressure), water boils below 100°C.
Is this converter free?
Yes, completely free with no registration needed.