Kelvin to Celsius, Fahrenheit & More Converter
Enter a temperature in kelvin to convert it to Celsius, Fahrenheit, Rankine, Newton, Delisle, Réaumur, and Rømer.
Kelvin Temperature Conversion Tool
Kelvin Temperature Conversion Formula
Where:
- \(K\) — temperature in kelvin (K).
- \(C\) — temperature in degrees Celsius (°C).
- \(F\) — temperature in degrees Fahrenheit (°F).
- \(Ra\) — temperature in degrees Rankine (°R).
- \(N\), \(De\), \(Re\), and \(R\o\) — temperatures in degrees Newton, Delisle, Réaumur, and Rømer, respectively.
First subtract 273.15 to find the Celsius temperature. The remaining formulas convert that value to other scales, except Rankine, which is calculated directly from kelvin. The calculator uses decimal approximations for the Newton and Rømer conversions, so its last displayed digits may differ slightly from calculations using the fractions above.
Kelvin Temperature Conversion – Calculation Example
Example: Convert the calculator’s default temperature of 300 K to every available scale.
Start with Celsius, then use it for the conversions that depend on it:
\[C=300-273.15=26.85\,^{\circ}\mathrm{C}\]
\[\begin{aligned}F&=\frac{9}{5}(26.85)+32=80.33\,^{\circ}\mathrm{F}\\Ra&=\frac{9}{5}(300)=540\,^{\circ}\mathrm{R}\\N&=\frac{33}{100}(26.85)=8.8605\,^{\circ}\mathrm{N}\\De&=\frac{3}{2}(100-26.85)=109.725\,^{\circ}\mathrm{De}\\Re&=\frac{4}{5}(26.85)=21.48\,^{\circ}\mathrm{Re}\\R\o&=\frac{21}{40}(26.85)+7.5=21.59625\,^{\circ}\mathrm{R\o}\end{aligned}\]
Result: 300 K is 26.85 °C, 80.33 °F, 540 °R, approximately 8.86 °N, 109.725 °De, 21.48 °Re, and approximately 21.60 °Rø. Displayed results may be rounded.
How to use the calculator
- Enter your value in the Temperature in Kelvin field. For example, enter 300 for 300 K; do not add the unit to the number.
- Read the converted values under Celsius, Fahrenheit, Rankine, Newton, Delisle, Reaumur, and Rømer.
- Check the unit beside each result. If you need a different starting scale, use the Celsius converter or Fahrenheit converter instead.
What a kelvin conversion tells you
Kelvin is the SI base unit of thermodynamic temperature. Its zero point is absolute zero, the lower limit of thermodynamic temperature. A temperature in kelvin is written with K, not °K. Celsius has the same-sized degree as kelvin but a different zero point: 273.15 K equals 0 °C. This makes the subtraction of 273.15 the essential first step in most conversions on this page.
Fahrenheit is commonly used for everyday temperatures in the United States, while Celsius is common in weather reports and many practical settings elsewhere. Rankine, like kelvin, starts at absolute zero, but one Rankine degree is the size of one Fahrenheit degree. That is why a kelvin value is multiplied by 1.8 to obtain Rankine, without an added offset. If your starting value is already in Rankine, use the Rankine converter.
Newton, Delisle, Réaumur, and Rømer are historical temperature scales. Their numbers cannot be interpreted as Celsius or Fahrenheit values: each scale sets its own reference points and degree size. Delisle also runs in the opposite direction from Celsius over the usual reference range—a higher Celsius temperature produces a lower Delisle reading. The calculator gives equivalent temperatures, not changes in temperature.
Reference points and practical limits
Two useful checks are 273.15 K = 0 °C = 32 °F and 373.15 K = 100 °C = 212 °F. The latter is the boiling point of pure water at standard atmospheric pressure; water’s actual boiling temperature changes with pressure. At 0 K, the Celsius and Fahrenheit equivalents are −273.15 °C and −459.67 °F.
Enter an absolute temperature, not a temperature difference. For example, a rise of 10 K is also a rise of 10 Celsius degrees; subtracting 273.15 from that difference would be incorrect. Kelvin temperatures cannot be below 0 K, and the calculator’s input has a minimum of zero. Fractional kelvin values are valid when your measurement calls for them.
Converted values may be rounded for display, so avoid treating extra digits as measurement precision. The Newton and Rømer calculations in the tool use approximate decimal divisors rather than the exact fractions shown in the formula. For ordinary inputs the difference is very small, but when comparing results at high precision, calculate with the exact fractions and round only at the end. If you have a temperature on the historical Delisle scale to convert back, use the Delisle converter.
Frequently Asked Questions
How do I convert kelvin to Fahrenheit in one step?
Multiply the kelvin value by 1.8, then subtract 459.67: \(^{\circ}\!F=1.8K-459.67\). For example, 290 K is \(1.8(290)-459.67=62.33\,^{\circ}\mathrm{F}\). This combines the Celsius and Fahrenheit conversions into one calculation and is useful when checking a result by hand.
How do I convert Celsius or Fahrenheit back to kelvin?
Add 273.15 to a Celsius temperature: \(K=^{\circ}\!C+273.15\). For Fahrenheit, use \(K=(^{\circ}\!F+459.67)\times5/9\). For example, 68 °F equals 293.15 K. Keep the decimal offset even if you plan to round the final answer; rounding early can change the result.
What is a typical room temperature in kelvin?
Room temperature is often taken as roughly 293–298 K, equivalent to 20–25 °C. There is no single universal value: a laboratory procedure, product specification, or reference table may define room temperature differently. Use the temperature stated by your source when an exact value matters.
How much is a change of 1 kelvin in other temperature units?
A change of 1 K equals a change of 1 Celsius degree or 1.8 Fahrenheit degrees. It also equals a change of 1.8 Rankine degrees. These are temperature differences, not equivalent readings: a temperature of 1 K is not 1 °C. Delisle readings move in the opposite direction, decreasing by 1.5 °De for each 1 K increase.
Can a temperature actually reach 0 K?
No physical cooling process is known to reach exactly 0 K. Absolute zero is a theoretical limit, although experiments can get extremely close. A value of 0 K is still useful as the Kelvin scale’s reference point and for checking conversions; it should not be taken as a routinely measurable temperature.
Why can a Delisle temperature be negative?
The Delisle scale decreases as temperature rises. It assigns 150 °De to water’s freezing point and 0 °De to its boiling point at standard atmospheric pressure. A temperature above that boiling point therefore has a negative Delisle reading. A negative °De value does not mean the temperature is below absolute zero.
Why do gas-law calculations use kelvin instead of Celsius?
Gas laws such as the ideal gas law use absolute temperature, so their temperature input must be in kelvin. Celsius has an offset zero: substituting 0 °C as zero temperature would give the wrong relationship between temperature, pressure, and volume. Convert the actual Celsius reading to kelvin before using it in a gas-law equation.
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