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Convert between Celsius, Fahrenheit, and Kelvin instantly. Learn the exact formulas, understand why temperature scales differ, and find common temperature references for weather, cooking, science, and body temperature.
Temperature conversion is one of the most commonly needed conversions in daily life. The United States uses the Fahrenheit scale for weather and everyday temperature, while the rest of the world uses Celsius. Scientists worldwide use the Kelvin scale for absolute temperature measurements.
The formula to convert Celsius to Fahrenheit is: °F = (°C × 9/5) + 32. To convert Fahrenheit to Celsius: °C = (°F − 32) × 5/9.
Kelvin is the SI unit of temperature used in science and engineering. Unlike Celsius and Fahrenheit, Kelvin starts at absolute zero — the coldest possible temperature where all molecular motion stops. K = °C + 273.15.
For a quick Celsius to Fahrenheit estimate: double the Celsius and add 30. For example, 20°C → (20×2)+30 = 70°F (actual is 68°F — close enough for everyday use).
| Landmark Temperature | °C | °F | K |
|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 |
| Water Freezes | 0 | 32 | 273.15 |
| Body Temperature | 37 | 98.6 | 310.15 |
| Water Boils | 100 | 212 | 373.15 |
| Oven (moderate) | 180 | 356 | 453.15 |
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Results are based on the formula and inputs provided. For important financial, medical, or legal decisions, always verify results with a qualified professional. This tool is designed to give quick, reliable estimates for planning and educational purposes.
Always double-check your input values and units before calculating. Small input errors can significantly affect results. Use the Reset button to clear all fields and start fresh. For multi-step calculations, use the result of one calculation as the input for the next.
| Term | Meaning | Example |
|---|---|---|
| Input | Value you enter into the calculator | Amount, rate, or quantity |
| Output | Calculated result shown after clicking Calculate | Final answer or converted value |
| Formula | Mathematical equation used for the calculation | Shown in Formula section above |
| Precision | Number of decimal places in the result | Typically 2-4 decimal places |
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