Temperature Conversion

Thermodynamics & Universal Temperature Scale Physics

Temperature is a thermodynamic measure of average microscopic molecular kinetic energy.

Primary Temperature Conversion Equations

• Celsius to Fahrenheit: T_F = (T_C × (9) / (5)) + 32

• Fahrenheit to Celsius: T_C = (T_F - 32) × (5) / (9)

• Celsius to Kelvin: T_K = T_C + 273.15

• Kelvin to Celsius: T_C = T_K - 273.15

• Celsius to Rankine: T_R = (9) / (5)

• Celsius to Réaumur: T_Ré = T_C × (4) / (5)

Fundamental Thermodynamic Benchmarks

• Absolute Zero (0 K): -273.15^ (-459.67^) Complete cessation of thermal motion.

• Water Freezing Point (1 atm): 0.00^

• Human Body Temperature: 37.00^

• Water Boiling Point (1 atm): 100.00^

How to Use This Calculator

Enter your Temperature Value (e.g. 100) and Input Temperature Scale — choose from Celsius (°C — Metric Standard), Fahrenheit (°F — US Customary), Kelvin (K — SI Thermodynamic Base). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Formula Reference: Temperature Conversion

Input variables:

temperatureInputValue — Temperature Value

fromTemperatureScaleSelect — Input Temperature Scale

Computed outputs:

celsiusResult — Celsius

fahrenheitResult — Fahrenheit

kelvinResult — Kelvin

rankineResult — Rankine

reaumurResult — Réaumur

Mathematical relationships extracted from calculation logic:

c = (val - 32) * (5 / 9)

f = (c * (9 / 5)) + 32

k = c + 273.15

r = (c + 273.15) * (9 / 5)

re = c * (4 / 5)

Standard: NIST Handbook 44 and BIPM SI unit definitions

Worked Example

A cooking recipe calling for an oven temperature of 100°C converts to 212°F (373.15 K), representing the exact phase transition boiling point of water.

Understanding Your Result

Key temperature reference points: Absolute zero 0 K / −273.15°C / −459.67°F. Water freezes at 0°C / 32°F / 273.15 K. Water boils at 100°C / 212°F / 373.15 K at 1 atm (sea level). Human body temperature 37°C / 98.6°F. Oven baking range: 150–230°C / 300–450°F. Kelvin is always used in thermodynamic equations — never negative. Temperature differences in Celsius and Kelvin are equal: a 10°C rise = a 10 K rise.