Temperature Converter
Convert between any two kelvin units in your browser — instant, accurate, and private.
Example
1 °C = 33.8 °F. Switch the unit menus to convert between any pair.
How it works
Every value is converted through a single kelvin base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Temperature conversion sits at the crossroads of everyday life and hard science. Most of the world reports the weather, body temperature, and oven settings in Celsius, while the United States, its territories, and a handful of others stick with Fahrenheit — so a recipe, a thermostat, or a travel forecast often needs translating. Kelvin and Rankine, by contrast, live mostly in laboratories and engineering: Kelvin underpins physics and chemistry because it starts at absolute zero, and Rankine is its Fahrenheit-scaled cousin still used in some US thermodynamics and HVAC work.
The four scales come from different eras and goals. Celsius (1742) anchors itself to water's freezing point (0) and boiling point (100) at sea level, a clean metric-friendly 100-degree span. Fahrenheit (1724) is older and finer-grained, putting water's freeze at 32 and boil at 212 — a 180-degree span. Kelvin shares Celsius's degree size but slides the zero down to absolute zero (−273.15 °C), and Rankine shares Fahrenheit's degree size with its zero also at absolute zero (−459.67 °F).
A handy mental shortcut for Celsius to Fahrenheit: double the Celsius number and add 30 for a rough answer (20 °C ≈ 70 °F, true value 68 °F). Going the other way, subtract 30 and halve. For the absolute scales, just remember that Kelvin = Celsius + 273.15 and Rankine = Fahrenheit + 459.67 — no multiplying needed, since each pair shares a degree size.
The most common mistake is treating temperatures like simple ratios. A degree interval converts differently from a temperature point: a change of 5 °C equals a change of 9 °F, but 5 °C as a reading is 41 °F, not 9. Also watch the offset constants — using 273 instead of 273.15, or 460 instead of 459.67, introduces small errors that matter in scientific work even though they vanish in casual weather talk.
Frequently asked questions
What does the temperature converter do?
It converts between common kelvin units instantly. Pick a unit to convert from and a unit to convert to, type a value, and the result updates live.
Which units does this converter support?
It includes 4 units: Celsius, Fahrenheit, Kelvin, Rankine.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
What is normal body temperature in Fahrenheit and Celsius?
Average normal body temperature is about 37 °C, which equals 98.6 °F. Readings between roughly 36.1 °C (97 °F) and 37.2 °C (99 °F) are generally considered normal.
At what temperature are Celsius and Fahrenheit the same?
They meet at −40 degrees: −40 °C equals −40 °F exactly. It is the only point where the two scales read the same number.
How do you convert Celsius to Kelvin?
Add 273.15 to the Celsius value. For example, 25 °C = 298.15 K, and 0 °C = 273.15 K.
What is 100 degrees Fahrenheit in Celsius?
100 °F is about 37.78 °C. You subtract 32 and multiply by 5/9: (100 − 32) × 5/9 ≈ 37.78.
What is absolute zero in each temperature scale?
Absolute zero is 0 K and 0 °R (Rankine), which equals −273.15 °C and −459.67 °F. It is the lowest possible temperature, where molecular motion is minimal.
How do you convert Fahrenheit to Rankine?
Just add 459.67 to the Fahrenheit value, since both scales use the same degree size. For example, 70 °F = 529.67 °R.
What is a quick way to estimate Celsius to Fahrenheit in your head?
Multiply the Celsius number by 2 and add 30 for a fast approximation. So 20 °C ≈ 70 °F (the exact value is 68 °F).
What temperature does water boil in Kelvin and Rankine?
Water boils at 100 °C, which is 373.15 K and 671.67 °R at standard sea-level pressure. It freezes at 273.15 K and 491.67 °R.
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