Last updated: March 28, 2026
Converting Celsius to Fahrenheit relies on a straightforward formula: multiply the Celsius temperature by 9/5 (or 1.8), then add 32. Written out, that looks like F = C × 9/5 + 32. The multiplication accounts for the difference in degree size between the two scales—a single Fahrenheit degree is smaller than a Celsius degree, so you need more of them to cover the same range. The addition of 32 accounts for the fact that the two scales have different zero points: water freezes at 0°C but at 32°F.
Let’s walk through a practical example. Normal human body temperature is 37°C. Plugging that into the formula: 37 × 9/5 = 66.6, and 66.6 + 32 = 98.6. So 37°C equals 98.6°F—exactly the figure your doctor expects to see. This two-step process (scale then shift) is what makes temperature conversion different from simpler unit conversions like kilometers to miles, where a single multiplication factor is enough.
Understanding why the formula works helps you remember it. Anders Celsius designed his scale around water: 0 for freezing, 100 for boiling. Daniel Fahrenheit chose different reference points entirely, placing water’s freezing point at 32 and boiling point at 212. That gives Fahrenheit 180 degrees between the same two physical events that Celsius covers in 100 degrees. The ratio 180/100 simplifies to 9/5, which is the multiplier in the formula. The +32 then shifts the result so freezing lines up correctly.
| Celsius (°C) | Fahrenheit (°F) |
|---|---|
| -40 | -40 |
| -30 | -22 |
| -20 | -4 |
| -10 | 14 |
| 0 | 32 |
| 5 | 41 |
| 10 | 50 |
| 15 | 59 |
| 20 | 68 |
| 25 | 77 |
| 30 | 86 |
| 37 | 98.6 |
| 40 | 104 |
| 50 | 122 |
| 60 | 140 |
| 70 | 158 |
| 80 | 176 |
| 90 | 194 |
| 100 | 212 |
| 200 | 392 |
Knowing a few key temperature equivalents by heart makes everyday life easier, especially if you travel between countries that use different scales. Here are the most useful reference points:
Body temperature: 37°C = 98.6°F. This is normal body temperature for most adults, and it’s the most commonly converted medical temperature. A reading above 38°C (100.4°F) is generally considered a fever.
Water freezing: 0°C = 32°F. Below this, roads ice over and pipes can freeze. This is the foundational reference point of the Celsius scale.
Water boiling: 100°C = 212°F. At standard atmospheric pressure, water boils at this temperature. This defines the upper anchor of the Celsius scale.
Room temperature: 20–22°C = 68–72°F. This is the comfortable indoor range most thermostats target.
Oven temperatures: Common baking temperatures include 180°C (356°F) for cakes and cookies, 200°C (392°F) for roasting vegetables, and 220°C (428°F) for pizzas and bread. Converting oven temperatures accurately matters because even a small difference can affect your results.
Temperature conversion is not a simple multiplication—it involves both a scaling factor and an offset. Many quick-conversion tools get this wrong or only handle basic conversions. Our calculator applies the exact formula every time, so you can trust the result whether you’re converting body temperatures, weather forecasts, or industrial readings.
The converter works entirely in your browser, which means it runs offline once the page has loaded. There is no server round-trip, so results appear instantly as you type. Beyond Celsius and Fahrenheit, we also support conversions to and from Kelvin, which is essential for scientific and engineering work. Everything is free, with no sign-up required.