Temperature Converter

Temperature measures how hot or cold a body is relative to a reference. Celsius (°C) anchors everyday weather and cooking in most countries. Fahrenheit (°F) remains common in the United States for weather and ovens. Kelvin (K) is the SI absolute scale: 0 K is absolute zero and room temperature is about 293 K.

Reference points at standard pressure

Absolute zero and Kelvin

Kelvin never uses degrees in formal notation (write 300 K, not 300°K). Negative Kelvin values are impossible in classical thermodynamics. Celsius can be negative; Fahrenheit can be negative as well, but both scales cross absolute zero only in theoretical discussion.

Frequently asked questions

Is Celsius the same size as Kelvin?

Yes for differences: a change of 1 °C equals a change of 1 K. Only the zero points differ by 273.15.

Why do US forecasts use Fahrenheit?

Historical convention. The scale was defined before SI adoption and remains familiar to US audiences.

Can Kelvin be negative?

Not in classical thermodynamics. Negative Celsius or Fahrenheit values are common; Kelvin starts at absolute zero.

Do heat and temperature convert the same way?

No. This tool converts temperature scales. Heat energy depends on mass and specific heat capacity.

Which scale do scientists prefer?

Kelvin for thermodynamics and gas laws; Celsius for everyday lab work when offsets are easier to interpret.

Does altitude change boiling point?

Yes. Water boils below 100 °C at higher elevation because atmospheric pressure is lower. Temperature conversions still use the same formulas.

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Conversions pass through Celsius. From Fahrenheit: °C = (°F - 32) × 5/9. To Fahrenheit: °F = °C × 9/5 + 32. Kelvin: K = °C + 273.15 and °C = K - 273.15.

Kelvin and Celsius share the same step size (1 K = 1 °C difference), so only the zero point changes. Never use the same offset when converting between Fahrenheit and Kelvin without going through Celsius first.

Enter the reading you have, pick the source scale and target scale, then submit. For mental math, convert to Celsius first, then to the final scale.

1. 1
   Type the temperature value you measured or read from a device.
2. 2
   Choose the scale of your input (From) and the scale you need (To).
3. 3
   Click Convert Temperature to see the result.
4. 4
   Cross-check against a known reference (for example 100 °C = 212 °F) if the reading seems wrong.

Different fields standardize on different scales. Pick the output scale that matches your audience or equipment.

Medical thermometers may default to °C or °F based on locale; always check the unit printed on the display.