Temperature scales require both a scale and an offset, so conversion uses an affine transform rather than a simple multiplier.
Open full converterCelsius to Fahrenheit
ExactCategory meaning
Temperature represents thermal state on a defined scale. Celsius and Fahrenheit use different interval sizes and zero points, while Kelvin is an absolute thermodynamic scale; Rankine provides an absolute scale using Fahrenheit-sized intervals.
Calculation method
Temperature uses affine conversion rather than one multiplication. The engine applies both a scale and an offset when required, and validates the physical lower bound so an input cannot represent a temperature below absolute zero.
Inputs below absolute zero are rejected by the deterministic range validation.
Published scale definitions establish the interval size, zero point, and physical lower bound for each unit. The converter applies the appropriate affine relationship before formatting the result for display.
About the converter’s methodologyChoose the right unit
Start with the measurement context, then select the symbol shown by the source. Every family below contains units compatible within this category.
Celsius and Fahrenheit use different zero points and interval sizes, so converting a reading requires both scale and offset.
Kelvin and Rankine begin at absolute zero; kelvin intervals match Celsius while Rankine intervals match Fahrenheit.
Choose a common direction and start with the units already selected.
Calculated examples
Each example is calculated from the same unit definitions used by the interactive converter, so the worked values stay consistent with the result above.
0 °C = 32 °F
100 °C = 212 °F
273.15 K = 0 °C
Avoid common mistakes
This converter handles temperature readings. A change of one degree Celsius has the same interval size as one kelvin, but converting an actual Celsius reading to kelvin also changes the zero point.
The unit name and symbol are kelvin and K. Celsius, Fahrenheit, and Rankine use their respective degree notation in this catalog.
Values below absolute zero are rejected rather than displayed as physically valid temperature conversions.
Unit field guide
These profiles focus on decisions that affect a real conversion: what the unit represents, where it appears, when to select it, and which similarly named quantity can produce the wrong result.
Celsius is a temperature scale whose interval has the same size as the kelvin. A Celsius reading converts to kelvin by accounting for the different zero point.
Fahrenheit is a temperature scale with a different zero point and interval size from Celsius. A Fahrenheit interval is five ninths of a kelvin.
A reading of 1 °F corresponds approximately to -17.222222222222222222 °C; this is not an interval factor.
The kelvin is the SI base unit of thermodynamic temperature. Its zero point is absolute zero, and one kelvin has the same interval size as one degree Celsius.
A reading of 1 K corresponds to -272.15 °C; this is not an interval factor.
Compatible catalog
These units all describe temperature. The converter applies the appropriate scale, offset, or reciprocal for the selected pair. The groups help you find the unit you need.
Celsius
Common temperature scale with water freezing near 0 °C at standard pressure.
°CFahrenheit
Temperature scale commonly used for weather and everyday readings in the United States.
°FKelvin
SI base unit of thermodynamic temperature; its interval size matches Celsius.
KRankine
Absolute temperature scale with intervals equal in size to degrees Fahrenheit.
°RTemperature conversion is useful when weather reports, recipes, equipment limits, or scientific data use a different scale.
Helpful answers
Celsius and Fahrenheit have different zero points as well as different interval sizes, so their conversion requires both a scale and an offset.
No. The converter’s physical range validation rejects temperature inputs below absolute zero.
Not always. A reading includes the scale’s zero-point offset, while an interval describes only a change. This page converts temperature readings selected in the converter.
Kelvin is written with the symbol K, not °K. Celsius, Fahrenheit, and Rankine use degree notation in their symbols.
Both begin at absolute zero. A Rankine interval has the same size as a Fahrenheit degree, while a kelvin interval has the same size as a Celsius degree.
Their zero points were defined differently. Kelvin and Rankine start at absolute zero, while Celsius and Fahrenheit use conventional reference points above absolute zero.