Convert Celsius (°C) to Triple Point of Water (TPW) instantly.
About these units
Celsius (°C)
The Celsius scale is one of the world's most widely used temperature scales, rooted in human experience and environmental observation. Defined so that water freezes at 0°C and boils at 100°C under standard atmospheric pressure, the scale provides intuitive benchmarks that align closely with everyday life, weather reporting, cooking, and basic heating or cooling applications. In scientific work, the Celsius scale aligns neatly with the kelvin: T(K) = T(°C) + 273.15, which preserves temperature intervals and ensures compatibility with thermodynamic equations. This makes Celsius suitable for most laboratory temperature measurements while maintaining convenience for ordinary use. Historically, the scale was reversed—originally, 0°C represented water's boiling point and 100°C its freezing point. It was later inverted to match modern intuitive expectations and became standardized internationally. Today, Celsius serves as a bridge between everyday perception and scientific rigor, striking a balance between practicality and precision.
Triple Point of Water (TPW)
The Triple Point of Water (TPW) is not a temperature scale but a defining thermodynamic condition where water exists simultaneously as solid, liquid, and vapor. This state occurs at a very precise temperature: 273.16 K (0.01°C) under a pressure of 611.657 pascals. The TPW was historically crucial because the kelvin was directly defined using this temperature. Prior to the 2019 SI redefinition, the triple point of water served as the anchor for the absolute temperature scale and was used to calibrate thermometers worldwide. This made high-precision thermometry simpler, as laboratories could reproduce the TPW by using sealed cells filled with highly pure water. Even though the kelvin is now defined through Boltzmann's constant, the TPW remains essential in metrology because it is one of the most reproducible physical phenomena known. Standard cells are still used for calibrations, research, and quality control in temperature-sensitive industries. The TPW embodies the elegance of thermodynamics: a single point where phase equilibrium meets the foundations of measurement.