Temperature scales are not all anchored at the same zero point. Celsius and Fahrenheit use offset zero points, while Kelvin and Rankine are absolute scales.

For reliable conversion, rewrite the source value in Kelvin first, then convert from Kelvin to the target scale. This keeps both the scaling factor and offset explicit.

Formule et exemple

Formula: convert through Kelvin. For example, K = °C + 273.15 and °F = (K - 273.15) × 9/5 + 32.

Example: 25 °C = 298.15 K = 77 °F.

Erreurs fréquentes et précautions

Do not treat absolute temperature conversions like pure multiplication; offsets matter.
Temperature differences and absolute temperatures are not converted the same way in every formula context.
Kelvin values cannot be negative in ordinary thermodynamic interpretation.

Cas d'usage pratiques

Temperature conversion is common in lab protocols, weather data, HVAC work, and material specifications where Celsius, Fahrenheit, and Kelvin are mixed.

Always check whether the value is an absolute temperature or a temperature difference before converting formulas in reports.

Références / sources

BIPM — SI Brochure (kelvin)
NIST SP 811 — Guide for the Use of SI
ISO 80000 — Quantities and units, thermodynamics