About

In the fields of thermodynamics, cryogenics, and astrophysics, the Kelvin (K) is the primary unit of measurement because it is an absolute scale starting at absolute zero. However, for practical reporting, equipment monitoring, and publication, these values are frequently converted to degrees Celsius (°C).

This tool performs the offset calculation required to shift between the absolute scale and the relative Celsius scale. It includes logic to validate physical possibilities, preventing inputs that violate the laws of thermodynamics (values below 0 K).

Formulas

The Celsius scale is defined relative to the Kelvin scale by a precise offset. The scales share the same magnitude per unit (a change of 1 K is identical to a change of 1 °C).

T_°C = T_K − 273.15

Constraint: T_K ≥ 0.

Reference Data

Description	Kelvin (K)	Celsius (°C)
Absolute Zero	0	-273.15
Liquid Nitrogen	77	-196.15
Dry Ice Sublimation	194.65	-78.5
Water Freezing Point	273.15	0
Standard Room Temp	293.15	20
Human Body	310.15	37
Water Boiling Point	373.15	100
Paper Autoignition	506.15	233
Lead Melting Point	600.65	327.5
Surface of Sun	5,778	5,505

Frequently Asked Questions

No. By definition, 0 K is "Absolute Zero", the theoretical point where all thermal motion of particles ceases. Therefore, negative Kelvin values are physically impossible in classical thermodynamics.

Kelvin is not referred to as "degrees". It is just "Kelvin". Celsius uses "degrees". The magnitude of one unit is the same, so no multiplication is needed, only subtraction.

This value arises from the definition of the triple point of water (0.01 °C or 273.16 K) and absolute zero. The offset aligns the freezing point of water (0 °C) with 273.15 K.

Yes, because the relationship is linear and the offset is constant, this formula remains valid for any positive temperature, from the cold of space to the center of stars.