Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin instantly. Free tool with precise calculations and real-time updates.
Temperature Reference
Conversion Formulas
°F = °C × 9/5 + 32 | K = °C + 273.15 | °C = (°F - 32) × 5/9
Temperature Converter: Celsius, Fahrenheit, Kelvin
Convert temperatures instantly between Celsius (°C), Fahrenheit (°F), and Kelvin (K). Whether you're traveling abroad, cooking an American recipe, or working in science, this tool gives you precise real-time conversions.
The three most commonly used temperature scales each have their domain: Celsius for everyday life (outside the USA), Fahrenheit in the United States, and Kelvin for science.
How to Use
- Enter a temperature in any field (Celsius, Fahrenheit, or Kelvin)
- Other fields update automatically in real-time
- Click the copy button to grab any value
Reference Temperatures
| Description | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Absolute zero | -273.15°C | -459.67°F | 0 K |
| Water freezing | 0°C | 32°F | 273.15 K |
| Body temperature | 37°C | 98.6°F | 310.15 K |
| Water boiling | 100°C | 212°F | 373.15 K |
💡 Fun fact: -40° is the same temperature in both Celsius and Fahrenheit!
Use Cases
🌍 Travel
Understand local weather when traveling to or from the United States.
👨🍳 Cooking
Convert oven temperatures from American recipes (350°F → 175°C).
🔬 Science
Work in Kelvin for thermodynamics and physics calculations.
🏥 Medicine
Convert body temperatures between measurement systems.
Why Use This Converter?
⚡ Instant
Real-time conversion with every character typed.
🔄 Bidirectional
Enter in any field, others update automatically.
🎯 Precise
Decimal precision calculations without excessive rounding.
⚠️ Validation
Alerts if temperature is below absolute zero.
📋 Easy Copy
Copy any value with one click.
🔒 Private
Everything happens in your browser, no data transmitted.
❓ Frequently Asked Questions (FAQ)
What are the conversion formulas?
Here are the conversion formulas between the three scales:
- 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
Fahrenheit and Kelvin can be converted using Celsius as an intermediate.
What is absolute zero?
Absolute zero is the lowest theoretically possible temperature. It corresponds to:
- 0 K (Kelvin)
- -273.15°C
- -459.67°F
At this temperature, the thermal motion of atoms theoretically stops. In practice, we can never reach exactly absolute zero, but scientists have gotten within billionths of a degree.
Why doesn't Kelvin have a degree symbol?
Kelvin is an absolute scale, not a relative scale like Celsius or Fahrenheit. The "°" (degree) symbol implies a relative measurement from an arbitrary reference point.
So we say "300 kelvins" not "300 degrees Kelvin". Kelvin is the base unit of temperature in the International System of Units (SI).
Are negative temperatures in Kelvin possible?
No, the Kelvin scale starts at absolute zero (0 K). A negative Kelvin temperature makes no physical sense in classical thermodynamics.
Note: in quantum physics, "negative temperatures" are sometimes discussed in special systems, but this refers to a population inversion state, not a temperature "colder" than absolute zero.
Why are there different temperature scales?
Each scale has its history and domain of use:
- Celsius (1742): Based on water (0° = freezing, 100° = boiling). Used in most of the world.
- Fahrenheit (1724): Based on a salt/water mixture (0°F) and the human body (~100°F). Used in the United States.
- Kelvin (1848): Scientific scale based on absolute zero. Used in physics and chemistry.