Temperature Converter
Convert temperature values across Celsius, Fahrenheit, Kelvin, and Rankine with instant mathematical precision.
Equivalent Values Across All Scales:
Understanding Temperature Scales and Thermodynamics
Temperature is a physical quantity that measures the average kinetic energy of the particles in a system. Unlike fundamental dimensions like mass or length, temperature scales are defined either by reference to physical phase changes of substances (such as the freezing and boiling points of pure water at standard atmospheric pressure) or by thermodynamic energy states relative to absolute zero.
Primary Temperature Scales Explained
Celsius (°C)
Defined in 1742 by Swedish astronomer Anders Celsius. Under the modern International System of Units (SI), Celsius is defined in terms of Kelvin, where 0°C is equal to 273.15 K. It is the international standard for daily weather, cooking, and science.
Fahrenheit (°F)
Proposed in 1724 by physicist Daniel Gabriel Fahrenheit. Widely used in the United States and several Caribbean nations. On this scale, the freezing point of water is 32°F and the boiling point is 212°F, creating a 180-degree interval.
Kelvin (K)
The SI base unit of thermodynamic temperature. Named after Lord Kelvin, this scale starts at absolute zero (0 K). Because it is an absolute scale, temperatures are expressed without the degree symbol (°).
Rankine (°R)
Proposed in 1859 by Scottish engineer William John Macquorn Rankine. Rankine is the absolute thermodynamic scale corresponding to Fahrenheit degrees (where 0°R = -459.67°F). It is used primarily in thermodynamics and aerospace engineering in the United States.
Exact Conversion Formulas
°F = (°C × 9/5) + 32
Celsius to Fahrenheit (or multiply by 1.8 and add 32)
°C = (°F − 32) × 5/9
Fahrenheit to Celsius (or subtract 32 and divide by 1.8)
K = °C + 273.15
Celsius to Kelvin
°R = (°C + 273.15) × 9/5 = °F + 459.67
Celsius or Fahrenheit to Rankine
Key Temperature Benchmarks Reference Chart
| Physical State / Event | Celsius (°C) | Fahrenheit (°F) | Kelvin (K) | Rankine (°R) |
|---|---|---|---|---|
| Absolute Zero (Molecular motion ceases) | -273.15 °C | -459.67 °F | 0 K | 0 °R |
| Equal Reading Point | -40 °C | -40 °F | 233.15 K | 419.67 °R |
| Freezing Point of Water (1 atm) | 0 °C | 32 °F | 273.15 K | 491.67 °R |
| Standard Room Temperature | 20 °C | 68 °F | 293.15 K | 527.67 °R |
| Human Body Temperature (Average) | 37 °C | 98.6 °F | 310.15 K | 558.27 °R |
| Boiling Point of Water (1 atm) | 100 °C | 212 °F | 373.15 K | 671.67 °R |