Fahrenheit converter
Convert one Fahrenheit temperature into Celsius, kelvins, Rankine, Delisle, Newton, Réaumur, and Rømer units in real time.
The startup example is ready to export as a validated XLSX workbook.
Temperature input
Converted temperatures
Conversion table
| Scale | Converted value | Formula from °F |
|---|---|---|
| Celsius | 20 °C | (°F – 32) × 5/9 |
| Kelvin | 293.15 K | (°F – 32) × 5/9 + 273.15 |
| Rankine | 527.67 °R | °F + 459.67 |
| Delisle | 120 °De | (212 – °F) × 5/6 |
| Newton | 6.6 °N | (°F – 32) × 11/60 |
| Réaumur | 16 °Ré | (°F – 32) × 4/9 |
| Rømer | 13.33 °Rø | (°F – 32) × 7/24 + 7.5 |
Values are calculated from one canonical Fahrenheit input. Displayed values are rounded to a practical precision; the XLSX workbook stores the underlying numeric results.
How to use the Fahrenheit converter
What this calculator does
This calculator translates a temperature stated in degrees Fahrenheit into seven other temperature scales. It is useful when a weather report, oven setting, laboratory note, engineering specification, or historical source uses a scale different from the one you need. The conversion is an exact mathematical identity within the definitions of the scales; it does not predict weather, account for measurement uncertainty, or decide whether a temperature is safe for a person, food, equipment, or a scientific process.
When to use it
Use it to read U.S. weather values in Celsius, compare an oven or process temperature with a metric specification, convert an absolute temperature to kelvins or Rankine, or interpret older scientific texts that use Delisle, Newton, Réaumur, or Rømer. For authoritative background on modern temperature units, see the NIST guide to SI temperature units.
How to calculate
- The calculator opens with a complete demonstration value of 68 °F. Its results are already displayed, and the Download Excel button is immediately available.
- Replace the number in Temperature in Fahrenheit with the value you want to convert. Use ordinary decimal notation, such as 98.6 or – 40. The page recalculates as you type.
- Read the main Celsius result first, then use the result cards or the conversion table for kelvins, Rankine, Delisle, Newton, Réaumur, and Rømer.
- Select Download Excel to create a current-state workbook containing the input, all outputs, formulas, and notes. Select Reset to clear the demonstration and all calculated content. Reset may disable Excel export until a complete valid Fahrenheit value is entered again.
Input guide
Temperature in Fahrenheit is the only editable control. It is required and accepts a plain finite decimal number with a period as the decimal separator. The supported physical domain begins at absolute zero, – 459.67 °F; lower values are rejected because they would imply a negative thermodynamic temperature. A realistic example is 68, representing a mild indoor temperature. Raising the input raises Celsius, kelvins, Rankine, Newton, Réaumur, and Rømer, while Delisle decreases because its scale runs in the opposite direction. Common mistakes include entering a comma as a decimal separator, appending “°F” inside the box, pasting scientific notation, or entering a value below absolute zero.
Output guide
Temperature in Celsius is the primary result, shown in degrees Celsius. Temperature in kelvins and Temperature in Rankine are absolute-scale values; zero on either corresponds to absolute zero. Temperature in Delisle is reversed, so hotter Fahrenheit values produce smaller Delisle values. Temperature in Newton, Temperature in Réaumur, and Temperature in Rømer are historical scale conversions. The three summary pills repeat the current Fahrenheit, Celsius, and kelvin values for quick scanning. The Conversion table lists each scale, the converted value, and the exact formula applied. All outputs are conversions, not recommendations or measurements.
Worked example
With the startup value of 68 °F, Celsius is calculated as (68 – 32) × 5/9 = 20 °C. Kelvin is then 20 + 273.15 = 293.15 K. Rankine is 68 + 459.67 = 527.67 °R. The same input produces 120 °De, 6.6 °N, 16 °Ré, and approximately 13.33 °Rø. These figures match the first-open cards, table, summary pills, accessible result announcement, and workbook checkpoints.
Learn more
The NIST conversion-factor appendix gives the standard Fahrenheit-to-Celsius and Fahrenheit-to-kelvin relationships. The National Weather Service temperature conversion resource provides a practical meteorological comparison of Fahrenheit, Celsius, kelvin, and Rankine.
How the formulas relate
Fahrenheit and Celsius are linear scales with different zero points and interval sizes. A Celsius degree spans 1.8 Fahrenheit degrees, so the Fahrenheit offset of 32 is removed before multiplying by 5/9. Kelvin uses the same interval size as Celsius but shifts the zero point to absolute zero. Rankine does the same for the Fahrenheit interval, so its conversion only adds 459.67.
°C = (°F – 32) × 5/9
K = (°F – 32) × 5/9 + 273.15
°R = °F + 459.67
Historical scales use their own zero points and interval sizes. Delisle decreases as temperature increases, unlike the other scales shown here. For a broader explanation of the kelvin as the SI thermodynamic unit, read NIST's introduction to the kelvin.
Interpretation and common pitfalls
Temperature values and temperature intervals are not always converted the same way. For an actual temperature, offsets matter: 32 °F is 0 °C. For a change in temperature, only the interval ratio matters: a rise of 18 °F equals a rise of 10 °C. Do not add 273.15 when converting a temperature difference between Celsius and kelvin because their interval sizes are identical.
Rounding can also create small apparent discrepancies. This page keeps canonical numeric values internally and rounds only for display. A weather station or published table may round earlier in its process, so converting the rounded result back may not reproduce the original reading exactly. The U.S. National Weather Service discusses these practical conversion effects in its meteorological resources.