ucUnitCloudInternational unit matrix

Mistake guide

Converting temperature like a factor

Celsius can be converted to Fahrenheit by multiplying with a factor.

01Assumption

Celsius can be converted to Fahrenheit by multiplying with a factor.

02Actually

Temperature scales have an offset zero point. The conversion is °F = °C × 1.8 + 32. Without the added 32 every result is wrong.

03Why

Celsius puts the freezing point of water at 0, Fahrenheit at 32. Because the two scales also have different degree sizes, both a factor and an offset are needed. Kelvin, by contrast, has no offset against Celsius, only a shifted zero point.

04Check

Use two fixed points as a check: 0 °C must give 32 °F and 100 °C must give 212 °F. Anyone multiplying by 1.8 alone gets 0 °F instead of 32 °F and spots the error immediately. With negative values always carry the signs.

Matching conversions

Celsius to Fahrenheit°C → °FTemperatureFahrenheit to Celsius°F → °CTemperatureCelsius to Kelvin°C → KTemperatureFahrenheit to Kelvin°F → KTemperature

Unit family: Temperature

Sources

BIPM SI BrochureSI base units, prefixes and official SI context.NIST Guide to SI Appendix BNIST conversion-factor method and non-SI factors.
When not to use

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.

Citation

Citation note: UnitCloud, mistake guide, sources reviewed: September 2026. Source basis: BIPM SI Brochure · NIST Guide to SI Appendix B.