Temperature conversion between Celsius, Fahrenheit, and Kelvin is a common task in science, engineering, cooking, and everyday life. Each scale has different reference points and increments, making mental math error-prone. This tool converts between all three scales instantly and displays the conversion formulas used, so you understand the math behind each result.
°C to °F
°F = (°C × 9/5) + 32
°C to K
K = °C + 273.15
°F to °C
°C = (°F - 32) × 5/9
| Reference | °C | °F | K |
|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 |
| Liquid Nitrogen | -196 | -320.8 | 77.15 |
| Dry Ice | -78.5 | -109.3 | 194.65 |
| Water Freezing | 0 | 32 | 273.15 |
| Room Temperature | 20 | 68 | 293.15 |
| Body Temperature | 36.6 | 97.88 | 309.75 |
| Fever | 39 | 102.2 | 312.15 |
| Pasteurization | 72 | 161.6 | 345.15 |
| Water Boiling | 100 | 212 | 373.15 |
| Oven (Hot) | 220 | 428 | 493.15 |
Click any row to use that temperature.
Enter a temperature value in any of the three input fields - Celsius, Fahrenheit, or Kelvin. The other two fields update instantly with the converted values. You can type negative values, decimals, and very large or small numbers. The tool also displays the conversion formula used for each calculation, a visual thermometer showing the relative position on the scale, and common reference points (water freezing, boiling, absolute zero, body temperature) for context. Toggle between showing results with 0 to 6 decimal places for precision control.
Temperature conversion is needed in scientific research where Kelvin is the standard SI unit, cooking and baking when recipes use a different temperature scale, weather reporting for international audiences accustomed to different scales, HVAC engineering and building climate control system design, industrial manufacturing processes with precise temperature requirements, medical applications where body temperature may be reported in different scales, and travel when visiting countries that use a different temperature standard than your home country.
The three temperature scales are related by linear equations. Celsius to Fahrenheit: F = (C * 9/5) + 32. Celsius to Kelvin: K = C + 273.15. Fahrenheit to Celsius: C = (F - 32) * 5/9. The Kelvin scale is an absolute thermodynamic scale where 0 K (-273.15°C) is absolute zero, the theoretical minimum temperature. The tool uses JavaScript's IEEE 754 double-precision floating-point arithmetic, providing 15-17 significant digits of precision. Results are rounded to the user-specified decimal places using toFixed() for display.
Multiply the Celsius temperature by 9/5 (or 1.8) and add 32. The formula is: °F = (°C × 9/5) + 32. For example, 100°C = (100 × 1.8) + 32 = 212°F. Enter any Celsius value in the tool to see the instant conversion.
Absolute zero is 0 Kelvin (-273.15°C or -459.67°F), the lowest theoretically possible temperature where all molecular motion ceases. It is a fundamental limit in thermodynamics and cannot be reached in practice, only approached asymptotically.
Fahrenheit (1724) was based on three reference points including brine freezing. Celsius (1742) uses water's freezing (0°) and boiling (100°) points at standard pressure. Kelvin (1848) starts at absolute zero for scientific calculations. Each was developed for different practical or scientific needs.
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