Free Temperature Converter
Convert between Fahrenheit, Celsius, and Kelvin instantly. Free temperature unit conversion calculator with common references.
Best next links
Go deeper without getting lost
We're using this page to help push you toward NumberPond's strongest calculators and category hubs — the pages most people actually want next.
Related hubs
Fahrenheit
72.0°F
Celsius
22.2°C
Kelvin
295.4 K
Formula
°F to °C: (°F − 32) × 5/9 | °C to °F: (°C × 9/5) + 32 | °C to K: °C + 273.15How Temperature Conversion Works
Unlike other unit conversions that use simple multiplication, temperature conversion requires both multiplication and addition because the Fahrenheit, Celsius, and Kelvin scales have different zero points and different degree sizes. This converter handles all three scales instantly.
The Three Temperature Scales
- Fahrenheit (°F) — used in the United States for weather, cooking, and daily life. Water freezes at 32°F and boils at 212°F.
- Celsius (°C) — used by most of the world and in all scientific contexts. Water freezes at 0°C and boils at 100°C, making it intuitive.
- Kelvin (K) — the SI unit of temperature used in physics and chemistry. Starts at absolute zero (0 K = −273.15°C). Note: Kelvin doesn't use the degree symbol.
Key Temperature Reference Points
- Absolute zero: 0 K / −273.15°C / −459.67°F
- Water freezes: 273.15 K / 0°C / 32°F
- Room temperature: ~295 K / 22°C / 72°F
- Body temperature: ~310 K / 37°C / 98.6°F
- Water boils: 373.15 K / 100°C / 212°F
Quick Mental Conversion Tips
For a fast Fahrenheit to Celsius estimate: subtract 30, then divide by 2. Example: 80°F → (80−30)/2 = 25°C (actual: 26.7°C — close enough for everyday use).
For Celsius to Fahrenheit: double the number and add 30. Example: 20°C → (20×2)+30 = 70°F (actual: 68°F).
These shortcuts aren't perfectly accurate but work well for weather and cooking estimates. For precise scientific work, use this converter or the exact formulas.
Frequently Asked Questions
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature, then multiply by 5/9. For example, 72°F: (72 − 32) × 5/9 = 22.2°C. A quick estimate: subtract 30 and divide by 2.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 (or 1.8), then add 32. For example, 25°C: (25 × 1.8) + 32 = 77°F. A quick estimate: double the Celsius value and add 30.
What is Kelvin used for?
Kelvin is the SI unit for temperature used in science and engineering. It starts at absolute zero (−273.15°C), the coldest possible temperature where molecular motion stops. To convert Celsius to Kelvin, simply add 273.15.
What temperature is the same in Fahrenheit and Celsius?
−40 degrees is the same in both Fahrenheit and Celsius. This is the only point where the two scales intersect: −40°F = −40°C.
What is normal body temperature in Celsius and Fahrenheit?
Normal human body temperature is about 98.6°F (37°C), though it can vary between 97°F and 99°F (36.1°C to 37.2°C) depending on the time of day and individual factors.