What is Temperature Converter?

The Temperature Converter lets you switch between Celsius, Fahrenheit, Kelvin, Rankine and Réaumur scales instantly. Type a value in any field and the others update in real time, with the live formula shown step by step underneath.

All five scales convert at once, so you can type into any field and read the rest. One-tap presets jump straight to common reference points — absolute zero, water freezing, room temperature, body temperature, water boiling — and a second row of oven presets covers everyday baking, with a UK/Australia gas mark shown whenever the temperature lands in oven range. The step-by-step panel shows the exact formula used for each conversion. Useful for recipes from other countries, weather reports abroad, oven settings on imported appliances, lab work in Kelvin, US engineering tables in Rankine, older European texts in Réaumur, and any time you need a fast sanity check on a number.

How to use

1. Enter a temperature value in any of the five fields (Celsius, Fahrenheit, Kelvin, Rankine or Réaumur), or tap a preset for a common reference point or oven temperature.
2. The other fields update automatically as you type, and the step-by-step panel shows the formula used for each conversion.
3. Click Clear to reset all fields and start a new conversion.

When to use

• Following a recipe that lists oven temperature in a scale your appliance doesn't use.
• Checking what 75°F means before packing for a trip to a country that uses Celsius.
• Converting Kelvin readings from a physics or chemistry problem to something intuitive.

Result

A traveler sees the weather forecast shows 35°C in Tokyo. They enter 35 in the Celsius field and instantly see it equals 95°F and 308.15 K.

FAQ

Why is 0°C equal to 273.15 K and not just 273?

The Kelvin scale starts at absolute zero, which sits 273.15 degrees below the freezing point of water. The fractional part comes from the original 1954 redefinition of the scale, which fixed the triple point of water at exactly 273.16 K.

What's the formula to convert Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit value, then multiply by 5/9. For example, 100°F − 32 = 68, and 68 × 5/9 ≈ 37.8°C. The converter does this automatically and shows the result to four decimal places.

Can temperature be negative in Kelvin?

Not in normal physics. Absolute zero (0 K, or −273.15°C) is the coldest possible temperature, where molecular motion stops. If you enter a negative Kelvin value, it converts mathematically, but it has no physical meaning.

Why do US weather reports use Fahrenheit when most countries use Celsius?

The US never officially switched to the metric system for everyday measurements. Fahrenheit places everyday weather in the 0–100 range, which some argue feels more granular, but the rest of the world standardised on Celsius decades ago.

Is 100°C really the boiling point of water?

At sea level, yes. Boiling point drops with altitude because air pressure decreases — water boils at roughly 93°C in Denver and around 71°C at the top of Everest. Pure water also boils slightly later than salty water.

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