📖 How to Use This Temperature Converter
1
Enter the temperature value - Type the number you want to convert.
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Select the source unit - Choose Celsius, Fahrenheit, or Kelvin.
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Select the target unit - Choose the unit you want to convert to.
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Get instant results - The converted value appears automatically as you type or change units.
🌡️ Understanding Temperature Scales
Temperature is a measure of the average kinetic energy of particles in a substance. Three main temperature scales are used worldwide:
- Celsius (°C): Also known as centigrade, used in most countries for daily temperature, weather, and scientific work. 0°C = freezing point of water, 100°C = boiling point of water at sea level.
- Fahrenheit (°F): Used primarily in the United States. 32°F = freezing point of water, 212°F = boiling point of water at sea level.
- Kelvin (K): The scientific absolute temperature scale used in physics and chemistry. 0 K = absolute zero (lowest possible temperature), no degree symbol used. Water freezes at 273.15 K, boils at 373.15 K.
📊 Temperature Conversion Formulas
Celsius to Fahrenheit: °F = (°C × 9/5) + 32
Fahrenheit to Celsius: °C = (°F - 32) × 5/9
Celsius to Kelvin: K = °C + 273.15
Kelvin to Celsius: °C = K - 273.15
Fahrenheit to Kelvin: K = ((°F - 32) × 5/9) + 273.15
Kelvin to Fahrenheit: °F = ((K - 273.15) × 9/5) + 32
💡 Common Temperature Reference Points
- Absolute Zero: -273.15°C = -459.67°F = 0 K
- Freezing point of water: 0°C = 32°F = 273.15 K
- Human body temperature: 37°C = 98.6°F = 310.15 K
- Room temperature: 20-22°C = 68-72°F = 293-295 K
- Boiling point of water: 100°C = 212°F = 373.15 K
🌍 Which Countries Use Celsius vs Fahrenheit?
- Celsius: Used by almost all countries worldwide (metric system)
- Fahrenheit: Used primarily in the United States, its territories, and a few other countries
- Kelvin: Used in scientific research and engineering globally
❓ Frequently Asked Questions
How do I convert Celsius to Fahrenheit quickly? ▼
Multiply °C by 9, divide by 5, then add 32. For quick mental approximation: multiply °C by 2 and add 30 (e.g., 20°C × 2 = 40 + 30 = 70°F, actual 68°F).
Why does the US use Fahrenheit instead of Celsius? ▼
Historical reasons - Fahrenheit was well-established before the metric system became popular. The US has not officially adopted the metric system for daily temperature measurement.
What is absolute zero and why can't we reach it? ▼
Absolute zero (0 K, -273.15°C) is the theoretical point where particles have minimum thermal motion. Quantum mechanics prevents reaching absolute zero because particles have zero-point energy.
Why doesn't Kelvin use a degree symbol? ▼
Kelvin is an "absolute" scale based on thermodynamics, not a "degree" scale. The correct notation is "K" not "°K".
At what temperature are Celsius and Fahrenheit equal? ▼
Celsius and Fahrenheit are equal at -40 degrees (-40°C = -40°F). This is the only temperature where both scales match.