Temperature in Celsius
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Equivalent temperature value
Accurate temperature conversion tool for Kelvin, Celsius, Fahrenheit, and Rankine
Convert Kelvin to Celsius instantly with precise calculations. Includes bidirectional conversion and detailed breakdowns for all temperature scales in 2026.
Professional temperature conversion for science, engineering, and everyday use
Convert Kelvin to Celsius with full precision using the exact formula: °C = K − 273.15. This offset is defined internationally by the SI system and applies universally across all scientific, engineering, and everyday temperature calculations without any approximation.
Switch seamlessly between Kelvin to Celsius and Celsius to Kelvin conversion modes. Get instant results across all major temperature scales including Fahrenheit and Rankine — all from a single input value, with a full detailed breakdown every time.
Essential for scientists, engineers, students, meteorologists, HVAC professionals, and industrial process controllers. Use this tool for thermodynamics calculations, laboratory work, climate data analysis, material testing, and any cross-scale temperature conversion need.
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The Kelvin (K) is the SI base unit of thermodynamic temperature, named after Scottish physicist William Thomson, 1st Baron Kelvin. Unlike Celsius or Fahrenheit, the Kelvin scale starts at absolute zero — the theoretical temperature at which all thermal motion ceases — and has no negative values. Celsius (°C), meanwhile, is an everyday temperature scale where 0°C is the freezing point of water and 100°C is the boiling point at standard atmospheric pressure.
The relationship between Kelvin and Celsius is a simple linear offset: °C = K − 273.15. The two scales have the same degree size — a 1 K change equals a 1°C change — they are simply shifted by 273.15 units. This means room temperature of approximately 293 K equals 19.85°C, and the boiling point of water at 373.15 K equals exactly 100°C. For the official SI definition of the Kelvin, see the International Bureau of Weights and Measures (BIPM).
Key fixed temperature reference points across the Kelvin and Celsius scales
The reference table below shows common Kelvin values converted to Celsius, Fahrenheit, and Rankine for quick scientific and engineering use.
| Kelvin (K) | Celsius (°C) | Fahrenheit (°F) | Rankine (°R) | Reference Point |
|---|---|---|---|---|
| 0 K | −273.15°C | −459.67°F | 0°R | Absolute Zero |
| 100 K | −173.15°C | −279.67°F | 180°R | Deep Cryogenic |
| 200 K | −73.15°C | −99.67°F | 360°R | Polar Winter |
| 273.15 K | 0°C | 32°F | 491.67°R | Water Freezing Point |
| 293.15 K | 20°C | 68°F | 527.67°R | Standard Room Temp |
| 300 K | 26.85°C | 80.33°F | 540°R | Warm Room |
| 310.15 K | 37°C | 98.6°F | 558.27°R | Human Body Temp |
| 373.15 K | 100°C | 212°F | 671.67°R | Water Boiling Point |
| 500 K | 226.85°C | 440.33°F | 900°R | Industrial Process |
| 1,000 K | 726.85°C | 1,340.33°F | 1,800°R | Furnace Temperature |
| 5,778 K | 5,504.85°C | 9,940.73°F | 10,400°R | Surface of the Sun |
The Kelvin scale was redefined in 2019 by the International Committee for Weights and Measures (CGPM). Instead of being defined relative to the triple point of water, the Kelvin is now defined by fixing the numerical value of the Boltzmann constant (k = 1.380649 × 10⁻²³ J/K). The practical conversion formula °C = K − 273.15 remains unchanged — only the fundamental definition was updated.
The Kelvin to Celsius conversion is one of the simplest in science — just a single subtraction. Here are the steps:
°C = K − 273.15 | K = °C + 273.15 | °F = (K − 273.15) × 9/5 + 32 | °R = K × 9/5
The Kelvin is the SI base unit of temperature, defined by the Boltzmann constant since the 2019 SI redefinition. It starts at absolute zero (0 K = −273.15°C) and has no upper limit. The Kelvin scale uses the same degree size as Celsius, making conversion a simple offset of 273.15 in either direction.
Absolute zero (0 K / −273.15°C) is the lowest possible temperature, where all atomic and molecular thermal motion theoretically ceases. It has never been achieved in practice — the coldest temperatures recorded in laboratory conditions reach within billionths of a kelvin above absolute zero, but never reach it.
Kelvin is the preferred temperature unit in all scientific disciplines because it starts at absolute zero and never has negative values, making thermodynamic equations cleaner and physically meaningful. Gas laws, blackbody radiation, entropy calculations, and quantum physics all use Kelvin as the standard temperature unit.
In mechanical and civil engineering, temperature is frequently used in material stress analysis, thermal expansion calculations, and HVAC system design. Converting between Kelvin and Celsius is essential when referencing scientific data (Kelvin) against practical site or workshop measurements (Celsius) on construction and industrial projects.
Celsius is used in everyday life across most of the world for weather forecasts, cooking, and body temperature. Kelvin is reserved for scientific and engineering contexts. The simple 273.15 offset means any Celsius value from a weather station or thermometer can be instantly converted to Kelvin for use in scientific calculations without any scaling adjustment.
In photography and lighting, colour temperature is expressed in Kelvin. A warm incandescent bulb glows at approximately 2,700 K (2,426.85°C), daylight sits around 5,500–6,500 K, and a clear blue sky can reach 10,000 K. Understanding the Kelvin to Celsius conversion helps contextualise these extreme temperature values.
Unlike Celsius (°C) and Fahrenheit (°F), the Kelvin unit is written simply as K — never as °K. This is a formal SI rule. Writing "°K" is incorrect. For example: 300 K is correct; 300°K is wrong. When converting, always confirm the input unit — a value of "300°" might refer to Celsius or Fahrenheit but never Kelvin, which always uses the plain K symbol.
The International Bureau of Weights and Measures (BIPM) maintains the official definition of the Kelvin, updated in 2019 to be based on the Boltzmann constant for improved precision and global consistency.
Visit BIPM →The National Institute of Standards and Technology (NIST) provides authoritative reference data for temperature scales, conversion constants, and thermodynamic properties used in engineering and research worldwide.
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