Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin instantly. Free online temperature conversion calculator.
What is Temperature Converter?
A temperature converter translates values between Celsius (°C), Fahrenheit (°F), and Kelvin (K) — the three temperature scales used worldwide. Celsius is the global scientific and everyday standard, Fahrenheit is used in the United States for weather and cooking, and Kelvin is the SI unit used in physics, chemistry, and engineering (where 0K is absolute zero). This tool handles the non-linear conversion formulas instantly, eliminating the mental math that's notoriously easy to get wrong.
How It Works
The tool applies the standard 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. The conversion updates in real-time as you type, and shows the result with appropriate decimal precision. It handles negative temperatures correctly (important for Celsius/Fahrenheit where scales cross at -40°) and prevents invalid Kelvin values (can't go below 0K).
Examples
100°C
212°F
72°F
22.22°C
Tips & Best Practices
Celsius and Fahrenheit scales cross at exactly -40° — it's the same temperature in both systems.
Room temperature is approximately 20-22°C (68-72°F). Body temperature is 37°C (98.6°F).
Absolute zero (0K = -273.15°C = -459.67°F) is the lowest theoretically possible temperature.
Quick Reference
| Description | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Absolute zero | -273.15°C | -459.67°F | 0 K |
| Water freezes | 0°C | 32°F | 273.15 K |
| Room temperature | 20°C | 68°F | 293.15 K |
| Body temperature | 37°C | 98.6°F | 310.15 K |
| Water boils | 100°C | 212°F | 373.15 K |
Common Use Cases
- •Converting weather temperatures between Celsius and Fahrenheit for international travelers
- •Translating cooking temperatures between Fahrenheit (US recipes) and Celsius (international ovens)
- •Converting scientific temperature measurements between Kelvin and Celsius for lab work
- •Understanding temperature specifications in product datasheets using different scales
- •Converting body temperature readings between scales for medical reference
- •Translating HVAC and thermostat settings when working with equipment using different scales
Frequently Asked Questions
What's the formula for Celsius to Fahrenheit?▼
°F = °C × 9/5 + 32. For example, 100°C = 212°F.
What are the formulas for converting between the scales?▼
Celsius to Fahrenheit is `°F = °C × 9/5 + 32`; Fahrenheit to Celsius is `°C = (°F − 32) × 5/9`. Kelvin is Celsius plus 273.15. The order of operations matters: subtract 32 before multiplying, or the answer will be wrong.
Why is there no degree symbol with Kelvin?▼
Because the kelvin is an absolute unit rather than a scale of degrees, so it is written 300 K, not 300 °K. It also means temperature differences in kelvin and Celsius are numerically identical — a rise of 5 K is a rise of 5 °C.
At what temperature do Celsius and Fahrenheit read the same?▼
At exactly −40, where −40 °C equals −40 °F. It is the one point at which the two scales intersect, which makes it a useful sanity check on any conversion.
How do I convert a temperature difference rather than a reading?▼
Use only the ratio and drop the offset. A difference of 10 °C equals a difference of 18 °F, because you multiply by 9/5 but do not add 32. Applying the full formula to a difference is a common error in engineering calculations.
Is body temperature really 98.6 °F?▼
That figure is an over-precise conversion of 37 °C from a 19th-century study. Normal body temperature varies by person, time of day and measurement site, and modern studies put the average slightly lower, nearer 36.6 °C. The apparent precision of 98.6 is an artefact of the unit conversion.
Further Reading
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