Temperature Conversion

Temperature Converter

Enter or edit a temperature in any supported scale to convert it instantly across eight temperature systems.

Celsius 20.00 °C Fahrenheit 68.00 °F Kelvin 293.15 K

Workbook ready for the demonstration values.

Temperature values

All fields represent the same physical temperature. Editing one field recalculates the other seven.

°C

Plain decimal number; minimum – 273.15.

°F

Plain decimal number; minimum – 459.67.

K

Plain decimal number; minimum 0 K.

°R

Plain decimal number; minimum 0 °R.

°De

Plain decimal number; maximum 559.725 °De.

°N

Plain decimal number; minimum – 90.1395 °N.

°Ré

Plain decimal number; minimum – 218.52 °Ré.

°Rø

Plain decimal number; minimum – 135.90375 °Rø.

Live conversion

Kelvin equivalent
293.15 K

The SI thermodynamic temperature corresponding to the entered value.

Celsius
20.00 °C
Fahrenheit
68.00 °F
Rankine
527.67 °R
Delisle
120.00 °De
20.00 degrees Celsius equals 293.15 kelvins and 68.00 degrees Fahrenheit.

Conversion table

Scale Symbol Equivalent value Relationship to Celsius
The rows are equivalent representations of one temperature, so a chart would not add a truthful comparison; the table keeps each scale's numerical convention explicit.

How to use this temperature converter

What this calculator does

This calculator converts one physical temperature among Celsius, Fahrenheit, kelvin, Rankine, Delisle, Newton, Réaumur, and Rømer. Each field is both an input and a synchronized equivalent: change any one value and the other seven are recalculated from the same canonical Celsius temperature. It is intended for unit conversion, checking historical temperature scales, laboratory notes, recipes, engineering references, and general comparison. It does not measure a real object's temperature, correct for pressure or altitude, or replace a calibrated thermometer. The modern SI unit for thermodynamic temperature is the kelvin; NIST explains the kelvin and exact Celsius/Fahrenheit relationships in its SI temperature guidance.

When to use it

Use the converter when a weather report or appliance specification is in a different scale than you normally use; when a science or engineering problem needs kelvins rather than degrees Celsius; when a historical source uses Réaumur, Rømer, Newton, or Delisle; or when you want to cross-check a manual conversion before recording it in a worksheet. Because all eight fields stay synchronized, it is also useful for quickly seeing familiar anchors such as freezing water or room temperature across several scales without re-entering the same measurement.

How to calculate

  1. The calculator opens with a ready-to-use demonstration of 20.00 °C. The matching values are already populated, the live result is finite, and the example XLSX workbook is immediately available.
  2. Click the field for the scale you know, replace its value with a plain decimal number, and use a period as the decimal separator. Do not type unit symbols, thousands separators, or scientific notation. The other seven fields update automatically.
  3. Read the large Kelvin equivalent and the compact Celsius, Fahrenheit, Rankine, and Delisle cards, then use the conversion table for all eight scales. The table's “Relationship to Celsius” column shows the formula applied after the source value has been normalized.
  4. Select Download Excel to create a current-state OOXML workbook containing the inputs, conversion results, formulas as explanatory text, and model checks. The workbook is rebuilt and byte-validated from the current controls at click time.
  5. Select Reset to clear the demonstration and every calculated result. Reset does not restore 20 °C; it leaves the data fields empty and disables the Excel action until you enter a complete valid temperature again.

Input guide

Temperature in CelsiusRequired plain decimal in °C when used as the source. The physical lower bound is – 273.15 °C. Example: 20. Higher values raise every directly oriented scale, while Delisle falls because its scale runs in the opposite direction. A common mistake is typing “20°C” instead of the number alone.
Temperature in FahrenheitRequired plain decimal in °F when used as the source, no lower than – 459.67 °F. Example: 68. Fahrenheit has a different zero point and degree size from Celsius. Do not apply a simple multiplier without the 32-degree offset.
Temperature in kelvinRequired plain decimal in K when used as the source, with 0 K as the minimum. Example: 293.15. Kelvin has the same interval size as Celsius but begins at absolute zero. The unit symbol is K, not °K.
Temperature in RankineRequired plain decimal in °R when used as the source, minimum 0 °R. Example: 527.67. Rankine is an absolute scale whose interval matches Fahrenheit. Negative Rankine values are rejected.
Temperature in DelisleRequired plain decimal in °De when used as the source. Example: 120. Its direction is reversed: hotter temperatures produce smaller Delisle numbers. The absolute-zero ceiling is 559.725 °De, so larger values are physically invalid.
Temperature in NewtonRequired plain decimal in °N when used as the source, minimum – 90.1395 °N. Example: 6.6. Newton intervals are 33/100 of a Celsius degree, so copying a Celsius value directly is not a conversion.
Temperature in RéaumurRequired plain decimal in °Ré when used as the source, minimum – 218.52 °Ré. Example: 16. Each Réaumur degree corresponds to 1.25 Celsius degrees. Keep the accented scale name separate from the numeric input.
Temperature in RømerRequired plain decimal in °Rø when used as the source, minimum – 135.90375 °Rø. Example: 18. The Rømer scale uses both a multiplier and a 7.5-degree offset, so a ratio alone gives the wrong result.

Output guide

Celsius, Fahrenheit, Kelvin, Rankine, Delisle, Newton, Réaumur, and Rømer are exact linear conversions of the same canonical temperature, displayed to two decimal places while the internal model retains full floating-point precision. Zero in Celsius, Fahrenheit, Newton, Réaumur, Delisle, or Rømer is simply that scale's chosen zero and does not imply absence of thermal energy. By contrast, 0 K and 0 °R are absolute zero. The summary pills repeat Celsius, Fahrenheit, and Kelvin for quick scanning, the large Kelvin equivalent emphasizes the SI scale, and the Conversion table lists all eight values with symbols and the formula relationship. These are conversions, not estimates or recommendations. NIST's SI conversion-factor guide documents the standard Celsius, Fahrenheit, and kelvin equations used as the modern anchor for the model.

Worked example

The startup example uses 20.00 °C. Celsius to Fahrenheit is (20 × 1.8) + 32 = 68.00 °F. Celsius to kelvin is 20 + 273.15 = 293.15 K. Rankine follows from the absolute Celsius value: (20 + 273.15) × 1.8 = 527.67 °R. The historical scales evaluate to 120.00 °De, 6.60 °N, 16.00 °Ré, and 18.00 °Rø. Those numbers match the first-open controls, result cards, conversion table, and workbook checkpoints.

Learn more

For the formal relationship between Celsius temperature and thermodynamic temperature, see NIST Special Publication 330's SI definition of Celsius temperature. It explains that a Celsius interval and a kelvin interval have the same magnitude while their scale origins differ by 273.15.

How the conversion model works

The calculator first converts the active source field to Celsius, then derives every other scale from that one canonical value. The core modern relationships are K = °C + 273.15 and °F = (°C × 9/5) + 32. Rankine is K × 9/5. The historical equations used here are °De = (100 – °C) × 3/2, °N = °C × 33/100, °Ré = °C × 4/5, and °Rø = °C × 21/40 + 7.5. Converting in the reverse direction algebraically inverts the same equation, so changing the source scale does not change the represented physical temperature.

Absolute-zero guard: every accepted source value must convert to a Celsius temperature of at least – 273.15 °C. That corresponds exactly to 0 K and – 459.67 °F. Values below that bound are rejected rather than silently converted.

The calculator deliberately does not graph the eight numbers. They are not eight independent observations; they are eight coordinate systems for the same scalar temperature. Plotting their raw magnitudes as bars would visually imply that a larger numeral means a hotter temperature, which is false across scales with different offsets, degree sizes, and even reversed direction such as Delisle. A keyed table is therefore the more faithful analytical presentation.