Apex Conversion

🌡️ Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin instantly with the correct formulas.

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Common Temperature Conversions

InputUnitResultUnit
0Celsius32Fahrenheit
100Celsius212Fahrenheit
37Celsius98.6Fahrenheit
32Fahrenheit0Celsius
212Fahrenheit100Celsius
0Celsius273.15Kelvin

Formula Reference

Celsius → Fahrenheit:   °F = (°C × 9/5) + 32
Fahrenheit → Celsius:   °C = (°F − 32) × 5/9
Celsius → Kelvin:       K  = °C + 273.15
Kelvin → Celsius:       °C = K − 273.15

About Temperature Conversions

Temperature measures the thermal energy of a substance — how energetically its particles are moving. Of the three scales in common use, Celsius is the most widely adopted worldwide. It places the freezing point of water at 0°C and the boiling point at 100°C at standard atmospheric pressure, making it intuitive for everyday weather and cooking.

Fahrenheit is used primarily in the United States. It places freezing at 32°F and boiling at 212°F, giving a 180-degree span between those two reference points. The scale was originally defined by Daniel Gabriel Fahrenheit in the early 18th century, using a brine solution for 0°F and estimated human body temperature for 96°F (later adjusted to 98.6°F).

Kelvin is the SI unit of thermodynamic temperature, used universally in scientific and engineering work. It shares the same degree increment as Celsius but starts at absolute zero (−273.15°C) — the theoretical point at which all molecular motion ceases. Kelvin values are never written with a degree symbol; you write '300 K', not '300°K'.

Frequently Asked Questions

What is normal human body temperature in Celsius and Fahrenheit?

Normal body temperature is approximately 37°C (98.6°F), though it naturally varies by about half a degree throughout the day and from person to person. Oral temperature above 38°C (100.4°F) is generally considered a fever.

At what temperature does water freeze and boil?

Water freezes at 0°C (32°F) and boils at 100°C (212°F) at standard sea-level atmospheric pressure (1 atm). At higher altitudes where pressure is lower, water boils at a lower temperature — for example, at about 95°C (203°F) in Denver, Colorado.

What is absolute zero?

Absolute zero is the lowest possible temperature: 0 Kelvin, which equals −273.15°C or −459.67°F. At this temperature, all thermal motion of particles theoretically stops. While scientists have come extremely close, absolute zero has never been fully achieved in practice.

Which countries use Fahrenheit?

The United States, its territories (Puerto Rico, Guam, etc.), the Bahamas, Belize, and the Cayman Islands officially use Fahrenheit for everyday temperature. Most other countries, and all scientific disciplines worldwide, use Celsius.

What is room temperature?

Room temperature is generally considered to be 20–22°C (68–72°F) in everyday contexts. The IUPAC (International Union of Pure and Applied Chemistry) defines 'standard' laboratory temperature as 25°C (77°F). For HVAC purposes, comfort conditions are often specified as 21°C (70°F).

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All conversion results are provided for general informational purposes only. Our formulas use internationally recognized conversion factors; however, rounding may affect precision. Do not rely on these results for professional, medical, legal, or engineering decisions without independent verification. Read our full disclaimer.