Kelvin (K)
The SI base unit of temperature used in science
The Kelvin (K) temperature scale has a history tied to the development of the thermometer and the scientific understanding of heat. Early temperature scales were arbitrary, calibrated to convenient but inconsistent reference points. Daniel Fahrenheit, Anders Celsius, and Lord Kelvin each contributed scales that served different scientific and practical needs. Today, the Kelvin scale is used in specific scientific, engineering, or everyday contexts where its characteristics — whether its absolute zero reference, convenient degree size, or alignment with familiar reference points — make it the most practical choice.
Accurate temperature measurement is critical in engineering, science, commerce, and everyday life. Using the correct unit and applying conversions precisely prevents errors that can be costly or dangerous in professional applications.
Conversion Table
| Unit | Symbol | 1 K = |
|---|---|---|
| Celsius | °C | -272.15 °C |
| Fahrenheit | °F | -457.87 °F |
| Rankine | °R | 1.8 °R |
Conversions Involving Kelvin
Common Uses of the Kelvin
- •Weather forecasting — reporting ambient air temperatures to the public
- •Cooking — setting oven and stovetop temperatures for recipes
- •Medicine — measuring body temperature for clinical diagnosis
- •Materials processing — controlling heat treatment for metals and plastics
- •Scientific research — conducting temperature-dependent experiments
Did You Know?
The coldest temperature ever recorded naturally on Earth was −89.2°C (−128.6°F), measured at the Soviet Vostok Station in Antarctica in 1983. The hottest was 56.7°C (134°F) in Death Valley, California, in 1913. The Kelvin scale places these extremes in context through its own reference points.