About

In thermodynamics, the Kelvin scale is the primary unit of measurement. Unlike Celsius or Fahrenheit, which are relative scales, Kelvin is an absolute scale. This means 0 K represents the complete absence of thermal energy, known as Absolute Zero. This distinction is critical in physics equations, such as the Ideal Gas Law (PV = nRT), where using relative temperatures results in catastrophic calculation errors.

This tool is engineered for students and researchers. It validates inputs against the physical limits of the universe (one cannot go below 0 K) and converts from both standard household scales. It uses the standard scientific constant 273.15 for precise conversion.

Formulas

The conversion relies on the shift of the zero point. The Kelvin degree magnitude is identical to Celsius.

From Celsius:

K = C + 273.15

From Fahrenheit:

K = F − 321.8 + 273.15

Constraint:

K ≥ 0

Note: Kelvin does not use the degree symbol (°). It is simply written as "K".

Reference Data

Physical State	Kelvin (K)	Celsius (°C)	Fahrenheit (°F)
Absolute Zero	0	-273.15	-459.67
Boomerang Nebula (Coldest Place)	1	-272.15	-457.87
Liquid Helium	4.2	-268.95	-452.11
Liquid Nitrogen	77	-196.15	-321.07
Dry Ice (Sublimation)	194.6	-78.5	-109.3
Triple Point of Water	273.16	0.01	32.02
Standard Temperature (STP)	273.15	0	32
Human Body	310.15	37	98.6
Lead Melts	600.6	327.5	621.5
Sun Surface	5,778	5,505	9,941

Frequently Asked Questions

In classical thermodynamics, no. 0 K is the absolute lower limit of thermal energy. While some quantum systems exhibit "negative temperature" properties, this refers to entropy states, not kinetic coldness.

273.15 is the precise offset defined by international standards bodies (SI). Using 273 introduces a 0.15-degree error, which is significant in chemical reaction calculations.

The tool will flag this as an error. -300°C is physically impossible as it is below Absolute Zero (-273.15°C).

Yes. It describes the color emitted by a black-body radiator at that temperature. 2700K is "warm" (orange/yellow), while 6500K is "cool" daylight (blue/white).