Kelvin Conversion Tool - Convert Kelvin to Any Unit
Convert Kelvin to Other Units
Quick Conversions
Convert Other Units to Kelvin
Quick Conversions
Related Temperature Units
Kelvin Conversion Table
This comprehensive Kelvin conversion table shows the formulas for converting Kelvin to other common temperature units. Use this reference for quick conversions.
| Conversion | To Unit | Formula |
|---|---|---|
| Kelvin to Celsius | Celsius (°C) | °C = K - 273.15 |
| Kelvin to Fahrenheit | Fahrenheit (°F) | °F = (K - 273.15) * 9/5 + 32 |
| Kelvin to Rankine | Rankine (°R) | °R = K * 9/5 |
| Kelvin to Réaumur | Réaumur (°Re) | °Re = (K - 273.15) * 4/5 |
This Kelvin conversion reference table provides accurate conversion formulas for both metric (SI) and imperial temperature scales.
What is a Kelvin?
The kelvin (symbol: K) is the base unit of thermodynamic temperature in the International System of Units (SI). It is defined based on the Boltzmann constant, which relates temperature to the kinetic energy of particles in a system. One kelvin is defined as the change in the thermodynamic temperature T that results in a change of thermal energy kT by 1.380649×10⁻²³ J.
The Kelvin scale is an absolute scale, meaning 0 K is absolute zero—the point at which all thermal motion ceases. Unlike Celsius or Fahrenheit, kelvin is not expressed in "degrees." It is used extensively in science and engineering, especially in fields like thermodynamics, cryogenics, and astrophysics.
What is the SI of Kelvin?
The kelvin is one of the seven base units in the International System of Units (SI), serving as the fundamental unit for measuring temperature. Other temperature scales are defined relative to the Kelvin scale:
- Celsius (°C): T(°C) = T(K) - 273.15
- Fahrenheit (°F): T(°F) = T(K) × 9/5 - 459.67
- Rankine (°R): T(°R) = T(K) × 9/5
What is Kelvin Used For?
The Kelvin scale is critical in many scientific and technical applications where absolute temperature is important:
Scientific Research
Used in physics, chemistry, and biology to describe the behavior of matter at different temperatures, from cryogenics (near 0 K) to plasma physics (millions of K).
Color Temperature
In lighting and photography, color temperature (measured in kelvins) describes the color of a light source. "Warm" light is around 2700 K, while "cool" or "daylight" is 5000-6500 K.
Electronics & Semiconductors
The performance of electronic components is often temperature-dependent, and Kelvin is used to specify operating ranges and thermal noise (e.g., noise temperature in sensors).
Astronomy & Astrophysics
Used to measure the surface temperature of stars and other celestial objects. For example, the surface of the Sun is approximately 5778 K.
Etymology and History
The Kelvin scale is named after the Belfast-born, Glasgow University engineer and physicist William Thomson, 1st Baron Kelvin (1824–1907). In 1848, he wrote a paper "On an Absolute Thermometric Scale," which proposed a scale starting from "infinite cold" (absolute zero).
This absolute scale was developed based on the principles of thermodynamics, independent of the properties of any specific substance. The unit was officially named the "kelvin" in 1967 by the 13th General Conference on Weights and Measures, and the "degree" symbol was dropped.
Frequently Asked Questions
Why is Kelvin the base SI unit for temperature?
Kelvin is the base SI unit because it is an absolute scale directly related to the kinetic energy of particles. Its zero point (0 K) is absolute zero, a fundamental physical limit. This makes it independent of the properties of any substance (like water, used for Celsius) and ideal for scientific laws and formulas.
What is absolute zero?
Absolute zero (0 K) is the lowest possible temperature, equivalent to -273.15 °C or -459.67 °F. At this temperature, particles have minimal vibrational motion, retaining only quantum mechanical zero-point energy. It is a theoretical limit that cannot be reached but can be closely approached in laboratory settings.
Is it "Kelvin" or "degrees Kelvin"?
The correct term is "kelvin" (symbol: K), not "degrees Kelvin." Unlike the Celsius and Fahrenheit scales, which are relative, the Kelvin scale is an absolute scale where the unit is simply the kelvin. The "degree" was officially dropped in 1967 to emphasize this distinction.
How do I convert Kelvin to Celsius?
To convert Kelvin to Celsius, simply subtract 273.15 from the Kelvin value. The formula is: °C = K - 273.15. For example, the boiling point of water, 373.15 K, is equal to 100 °C.
How do I convert Kelvin to Fahrenheit?
To convert Kelvin to Fahrenheit, first convert Kelvin to Celsius (K - 273.15), then multiply by 9/5, and finally add 32. The full formula is: °F = (K - 273.15) * 9/5 + 32. Our converter tool handles this calculation automatically.
Why is color temperature measured in Kelvin?
Color temperature uses the Kelvin scale because it relates to "black-body radiation," where a theoretical perfect black object emits light of a specific color as it heats up. Lower Kelvin values (e.g., 2700 K) correspond to reddish, "warm" light, while higher values (e.g., 6500 K) correspond to bluish, "cool" light, mimicking the color of a heated object.
Can temperature be negative in Kelvin?
No, temperatures on the Kelvin scale cannot be negative. The zero point, 0 K, is absolute zero, the lowest possible temperature. All temperatures are positive values, reflecting the amount of thermal energy in a system.
Is your Kelvin conversion tool free to use?
Yes, our Kelvin conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results for scientific, educational, or general use.