Temperature Converter

How to Use This Calculator

1. Enter the temperature value you want to convert.
2. Select the unit you are converting from (Celsius, Fahrenheit, or Kelvin).
3. Select the unit you want to convert to.
4. The converted value appears instantly in the result box.

Formula

Example

Frequently Asked Questions

• How do I convert Celsius to Fahrenheit? ▼
  To convert Celsius to Fahrenheit, use the formula °F = (°C × 9/5) + 32. Multiply the Celsius value by 1.8, then add 32. For example, 20°C becomes (20 × 1.8) + 32 = 36 + 32 = 68°F. For a quick mental estimate, double the Celsius value and add 30 (this gives 70°F for 20°C, which is close enough for everyday use). A common confusion is applying the formula in reverse: to go from Fahrenheit to Celsius, subtract 32 first and then multiply by 5/9. The factor 9/5 = 1.8 comes from the ratio of the Fahrenheit degree size to the Celsius degree size — one Fahrenheit degree is 5/9 the size of one Celsius degree, which is why the two scales cross at −40° (the only temperature where °C = °F).
• What is 37°C in Fahrenheit? ▼
  37°C is equal to 98.6°F, which is considered normal human body temperature. The calculation is: (37 × 9/5) + 32 = (37 × 1.8) + 32 = 66.6 + 32 = 98.6°F. In practice, normal body temperature varies from about 36.1°C (97°F) to 37.2°C (99°F) depending on the time of day, measurement location, and individual. A fever is generally defined as a temperature above 38°C (100.4°F). The Celsius value of 37°C is used as the clinical benchmark because it was established as the average oral temperature by German physician Carl Wunderlich in the 19th century using mercury thermometers, and the value has been retained as a convenient reference point.
• What is absolute zero in Celsius and Fahrenheit? ▼
  Absolute zero is the theoretically lowest possible temperature, defined as 0 K (zero Kelvin). In other scales, absolute zero equals −273.15°C and −459.67°F. At this temperature, particles have minimal thermal motion — their quantum ground-state energy is the lowest possible. Absolute zero cannot be reached in practice; the third law of thermodynamics states that it requires an infinite number of cooling steps. The coldest temperatures ever achieved in laboratory experiments are within a few billionths of a degree above absolute zero. The Kelvin scale starts at absolute zero and uses Celsius-sized degrees, making it the preferred scale for scientific work in physics, chemistry, and astronomy. To convert Kelvin to Celsius, subtract 273.15; to convert to Fahrenheit, use K = (°F + 459.67) × 5/9.
• What is the boiling point of water in all units? ▼
  Water boils at 100°C = 212°F = 373.15 K at standard atmospheric pressure (1 atm = 101.325 kPa, sea level). This is one of the two reference points used to define the Celsius scale (along with 0°C for the freezing point). A common point of confusion is that the boiling point changes with altitude: at 1,500 m (5,000 ft) above sea level, water boils at about 95°C (203°F); at the summit of Everest (8,849 m), it boils at approximately 70°C (158°F). This affects cooking times significantly. Water can also be superheated above 100°C in a microwave if the container is very clean and smooth, because nucleation sites for bubble formation are absent. At higher pressures, such as inside a pressure cooker, water boils at around 121°C (250°F), which speeds up cooking.
• What is the freezing point of water? ▼
  Water freezes at 0°C = 32°F = 273.15 K at standard atmospheric pressure. This is the temperature at which liquid water and ice are in equilibrium — the solid and liquid phases coexist. Adding dissolved substances (solutes) lowers the freezing point via freezing-point depression: seawater freezes at about −1.8°C (28.8°F), and roads are salted to prevent ice by lowering the freezing point to around −10°C (14°F). Pure water can actually be supercooled below 0°C without freezing if kept very still and undisturbed, but any disturbance triggers rapid crystallization. The freezing and melting points of water are the same at 0°C under standard conditions. Under increased pressure, the melting point of ice decreases slightly, which is why ice skating is possible — the blade pressure partially melts the surface.

Related Calculators