Temperature Converter
Convert between 6 temperature scales instantly with visual thermometer, comparison chart, and formulas
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All Scales Conversion
Your input value converted to every temperature scale simultaneously
Visual Comparison
See how your temperature compares across all scales
Conversion Formulas
Mathematical formulas used for this conversion with your live values
Temperature Reference Points
Common temperatures in everyday life and science
| Description | °C | °F | K | °R |
|---|---|---|---|---|
| Absolute Zero | −273.15 | −459.67 | 0 | 0 |
| Coldest Recorded (Earth) | −89.2 | −128.6 | 184.0 | 331.1 |
| Dry Ice Sublimation | −78.5 | −109.3 | 194.7 | 350.4 |
| Water Freezes | 0 | 32 | 273.15 | 491.67 |
| Refrigerator | 4 | 39.2 | 277.15 | 498.87 |
| Room Temperature | 20 | 68 | 293.15 | 527.67 |
| Human Body | 37 | 98.6 | 310.15 | 558.27 |
| Fever | 39 | 102.2 | 312.15 | 561.87 |
| Hot Coffee | 70 | 158 | 343.15 | 617.67 |
| Water Boils | 100 | 212 | 373.15 | 671.67 |
| Oven Baking | 180 | 356 | 453.15 | 815.67 |
| Paper Burns (Fahrenheit 451) | 233 | 451 | 506.15 | 911.07 |
| Iron Melts | 1,538 | 2,800 | 1,811 | 3,260 |
| Sun Surface | 5,505 | 9,941 | 5,778 | 10,400 |
Conversion History
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How Temperature Scales Work
Celsius
Invented by Anders Celsius in 1742. Based on water's freezing point (0°C) and boiling point (100°C) at standard pressure. Used worldwide for everyday temperature measurement.
Fahrenheit
Created by Daniel Fahrenheit in 1724. Water freezes at 32°F and boils at 212°F. Primarily used in the United States and a few Caribbean nations for weather and cooking.
Kelvin
The SI unit of temperature, named after Lord Kelvin. Starts at absolute zero (0 K = −273.15°C). Used in science, engineering, and colour temperature measurement.
Rankine
Proposed by William Rankine in 1859. Like Kelvin but uses Fahrenheit-sized degrees. Starts at absolute zero (0°R). Used in some US engineering applications.
Réaumur
Created by René Antoine Ferchault de Réaumur in 1730. Water freezes at 0°Ré and boils at 80°Ré. Historically used in Europe, now mainly in some food industries.
Delisle
Invented by Joseph-Nicolas Delisle in 1732. Unique inverted scale — higher values mean colder temperatures. Water boils at 0°De and freezes at 150°De. Historically used in Russia.
Frequently Asked Questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (or 1.8), then add 32. Formula: °F = (°C × 9/5) + 32. For example, 100°C = (100 × 1.8) + 32 = 212°F.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value, then multiply by 5/9. Formula: °C = (°F − 32) × 5/9. For example, 72°F = (72 − 32) × 5/9 = 22.22°C.
What is absolute zero?
Absolute zero is the lowest possible temperature where all molecular motion stops. It equals −273.15°C, −459.67°F, 0 K, and 0°R. It has never been fully achieved in a laboratory.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at −40°. So −40°C = −40°F. This is the only point where both scales intersect.
Why does the US use Fahrenheit?
The Fahrenheit scale was widely adopted in English-speaking countries before Celsius became the global standard. The US retained it due to cultural familiarity and the cost of switching infrastructure.
What is Kelvin used for?
Kelvin is the SI unit used in science, physics, chemistry, and engineering. It's also used for colour temperature in photography and lighting (e.g., 5500K daylight).
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