Convert Kelvin to Triple Point of Water
Convert kelvins to triple points of water instantly. 1 K = 0.0036608581 TPW — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Triple Point of Water to Kelvin converter for the reverse conversion.
Units explained
Kelvin
The kelvin (K) is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant k at exactly 1.380649×10⁻²³ J/K. Zero kelvin is absolute zero, the lowest temperature physically possible, and kelvin values are written without a degree sign.
Named for William Thomson, 1st Baron Kelvin, who in 1848 calculated the value of absolute zero (about −273 °C) and proposed an absolute thermodynamic scale. His title comes from the River Kelvin, which flows past the University of Glasgow in Scotland.
The universal temperature unit of science and engineering — physics, chemistry, astronomy, and materials science — and the standard for color temperature in photography, displays, and lighting (a 5600 K daylight bulb).
Proposed by William Thomson (Lord Kelvin) in 1848; adopted as an SI base unit by the 10th CGPM in 1954 and redefined through the fixed Boltzmann constant by the 26th CGPM, effective May 20, 2019.
Triple Point of Water
The triple point of water is the unique state at which ice, liquid water, and water vapor coexist in equilibrium — exactly 273.16 K (0.01 °C). Treated as a converter unit, 1 triple point of water equals exactly 273.16 kelvins.
Adopted as thermometry's master fixed point because it is exactly reproducible in a sealed glass cell, unlike freezing and boiling points, which shift with atmospheric pressure and dissolved impurities.
Calibration laboratories and the International Temperature Scale of 1990 (ITS-90); from 1954 to 2019 the kelvin itself was defined as exactly 1/273.16 of this temperature.
Fixed at exactly 273.16 K by the 10th CGPM in 1954; it remained the kelvin's defining point until the 2019 SI redefinition through the Boltzmann constant.
Kelvin to Triple Point of Water conversion formula
The exact relationship between kelvins and triple points of water:
To convert kelvins to triple points of water, multiply the value in kelvins by 0.003660858105. To reverse, multiply the value in triple points of water by 273.16.
Both units count upward from absolute zero, so 0 K = 0 TPW and the relationship is a pure ratio.
How to use this converter
Type a value into the calculator. The result in triple points of water updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Triple Point of Water to Kelvin converter for the reverse direction.
Step-by-step: convert kelvins to triple points of water
- Write down the temperature in kelvins (K).
- Multiply the value in kelvins by 0.003660858105.
- The result is the same temperature expressed in triple points of water (TPW).
- To reverse, multiply the value in triple points of water by 273.16 — or open the Triple Point of Water to Kelvin converter.
Worked examples
Example 1 — Convert 310.15 K to TPW (human body temperature):
310.15 × 0.003660858105 = 1.1354151413 TPW
Example 2 — Convert 373.15 K to TPW (the boiling point of water):
373.15 × 0.003660858105 = 1.3660492019 TPW
Kelvin to Triple Point of Water conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from kelvins to triple points of water:
| Kelvin [K] | Triple Point of Water [TPW] | Reference point |
|---|---|---|
| 0 | 0 | Absolute zero |
| 233.15 | 0.8535290672 | Where Celsius and Fahrenheit coincide (−40°) |
| 255.3722222222 | 0.9348814695 | Zero Fahrenheit (0 °F) |
| 273.15 | 0.9999633914 | Water freezes (0 °C / 32 °F) |
| 273.16 | 1 | Triple point of water |
| 283.15 | 1.0365719725 | Cool day (10 °C / 50 °F) |
| 293.15 | 1.0731805535 | Room temperature (20 °C / 68 °F) |
| 298.15 | 1.091484844 | Standard laboratory temperature (25 °C) |
| 303.15 | 1.1097891346 | Hot day (30 °C / 86 °F) |
| 310.15 | 1.1354151413 | Human body temperature (37 °C / 98.6 °F) |
| 313.15 | 1.1463977156 | Heat-wave day (40 °C / 104 °F) |
| 323.15 | 1.1830062967 | Hot tap water (50 °C / 122 °F) |
| 373.15 | 1.3660492019 | Water boils (100 °C / 212 °F) |
| 453.15 | 1.6589178503 | Moderate baking oven (180 °C / 356 °F) |
| 5778 | 21.1524381315 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
How many triple points of water is 1 kelvin?
How do I convert kelvins to triple points of water?
How do I convert triple points of water back to kelvins?
How many triple points of water is 373.15 kelvins?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (1 K = 0.0036608581 TPW) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- BIPM — International Temperature Scale of 1990 (ITS-90)
The internationally agreed practical temperature scale, defining fixed points (including the triple point of water at 273.16 K) and interpolation instruments used by national metrology institutes for thermometer calibration worldwide.
- CODATA Internationally Recommended Values of the Fundamental Physical Constants
Committee on Data of the International Science Council; authoritative source for the masses of fundamental particles (electron, proton, neutron) and the atomic mass constant.