Convert Celsius to Triple Point of Water
Convert degrees celsius to triple points of water instantly. TPW = (°C + 273.15) × 0.003660858105 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Triple Point of Water to Celsius converter for the reverse conversion.
Units explained
Celsius
The degree Celsius (°C) is the SI's everyday temperature unit. One degree Celsius is exactly the same size as one kelvin, with the zero point shifted so that 0 °C = 273.15 K. Water freezes near 0 °C and boils near 100 °C at standard atmospheric pressure.
Named for Swedish astronomer Anders Celsius, who in 1742 proposed a 100-degree scale between the boiling and freezing points of water. His original scale ran in reverse (0 at boiling, 100 at freezing); it was inverted to the modern direction shortly after his death.
The world's standard everyday temperature scale, used in nearly every country — including throughout India — for weather forecasts, cooking, medicine, science classrooms, and industry.
Devised by Anders Celsius at Uppsala University, Sweden, in 1742; the inverted modern form was in use by 1745, and the name 'degree Celsius' replaced 'degree centigrade' internationally at the 9th CGPM in 1948.
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.
Celsius to Triple Point of Water conversion formula
The exact relationship between degrees celsius and triple points of water:
To convert degrees celsius to triple points of water, add 273.15 to the value, then multiply by 0.003660858105. To reverse, multiply the value by 273.16, then subtract 273.15.
Reference anchors: water freezes at 0 °C = 0.9999633914 TPW and boils at 100 °C = 1.3660492019 TPW (at standard atmospheric pressure).
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 Celsius converter for the reverse direction.
Step-by-step: convert degrees celsius to triple points of water
- Write down the temperature in degrees celsius (°C).
- Add 273.15 to the value, then multiply by 0.003660858105.
- The result is the same temperature expressed in triple points of water (TPW).
- To reverse, multiply the value by 273.16, then subtract 273.15 — or open the Triple Point of Water to Celsius converter.
Worked examples
Example 1 — Convert 37 °C to TPW (human body temperature):
(37 + 273.15) × 0.003660858105 = 1.1354151413 TPW
Example 2 — Convert 100 °C to TPW (the boiling point of water):
(100 + 273.15) × 0.003660858105 = 1.3660492019 TPW
Celsius to Triple Point of Water conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees celsius to triple points of water:
| Celsius [°C] | Triple Point of Water [TPW] | Reference point |
|---|---|---|
| -273.15 | 0 | Absolute zero |
| -40 | 0.8535290672 | Where Celsius and Fahrenheit coincide (−40°) |
| -17.7777777778 | 0.9348814695 | Zero Fahrenheit (0 °F) |
| 0 | 0.9999633914 | Water freezes (0 °C / 32 °F) |
| 0.01 | 1 | Triple point of water |
| 10 | 1.0365719725 | Cool day (10 °C / 50 °F) |
| 20 | 1.0731805535 | Room temperature (20 °C / 68 °F) |
| 25 | 1.091484844 | Standard laboratory temperature (25 °C) |
| 30 | 1.1097891346 | Hot day (30 °C / 86 °F) |
| 37 | 1.1354151413 | Human body temperature (37 °C / 98.6 °F) |
| 40 | 1.1463977156 | Heat-wave day (40 °C / 104 °F) |
| 50 | 1.1830062967 | Hot tap water (50 °C / 122 °F) |
| 100 | 1.3660492019 | Water boils (100 °C / 212 °F) |
| 180 | 1.6589178503 | Moderate baking oven (180 °C / 356 °F) |
| 5504.85 | 21.1524381315 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 37 °C in TPW?
How do I convert degrees celsius to triple points of water?
How do I convert triple points of water back to degrees celsius?
At what temperature do the Celsius and Triple Point of Water scales read the same number?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (TPW = (°C + 273.15) × 0.003660858105) 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.