Celsius to Fahrenheit Converter
Convert Celsius to Fahrenheit for US weather, oven temperatures, and international travel.
How It Works
Formula: °C to °F = value × 1.8 + 32
Example: 25 °C = 77 °F
Note: Celsius converts to Fahrenheit using F = (C × 9/5) + 32, the standard formula for US temperature readings.
Common Uses
Quick Conversion Table
| °C | °F |
|---|---|
| -40 | -40 |
| 0 | 32 |
| 20 | 68 |
| 25 | 77 |
| 37 | 98.6 |
| 100 | 212 |
| 200 | 392 |
Rounding Rule
Rounded to 2 decimal places
Error Margin
±0.01°F
Precision Guidance
For weather, round to 1 decimal place. For oven settings, round to the nearest 5 degrees.
Common Mistakes
Temperature conversion is not a simple ratio—you must add 32 after multiplying by 9/5. Skipping the offset gives the wrong answer.
Frequently Asked Questions
What is 25°C in Fahrenheit?
25°C equals 77°F using the formula F = (C × 9/5) + 32.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (1.8) and add 32. For example, (25 × 1.8) + 32 = 77°F.
What is body temperature in Fahrenheit?
Normal body temperature is about 37°C, which equals 98.6°F.
Why does the US use Fahrenheit?
Fahrenheit is embedded in US weather, cooking, and daily life, making Celsius-to-Fahrenheit conversion common for international data.
Deep Dive Guide
Celsius to Fahrenheit: Complete US Conversion Guide for Weather and Cooking
Convert Celsius to Fahrenheit for US weather forecasts, oven temperatures, and international recipes. Master the C to F formula with practical examples.
Read Full Guide →More Converters You May Like
70°F to Celsius Converter
Convert 70°F to Celsius - the ideal room temperature for American homes.
80°F to Celsius Converter
Convert 80°F to Celsius for US summer daily weather reference.
90°F to Celsius Converter
Convert 90°F to Celsius - hot summer temperature for US cities.
Exact Constants & Authoritative Sources
Every conversion on this page uses the fixed, internationally agreed constants below — drawn from NIST and the SI Brochure. No values are estimated or rounded as if exact. See the full list on our Sources & Standards page.
- EXACT°F = °C × 9/5 + 32 (exact linear relation)
- EXACT°C = (°F − 32) × 5/9 (exact inverse relation)
- EXACTKelvin (K) = °C + 273.15 (exact offset)
- EXACTWater freezes at 0 °C = 32 °F and boils at 100 °C = 212 °F
Common Pitfalls & How to Avoid Them
Subtract 32 BEFORE multiplying
°C = (°F − 32) × 5/9. Doing 5/9 × °F − 32 instead gives a wrong answer because the offset must be removed first. Parentheses matter.
Degrees are not the same size
A 1 °C step equals a 1.8 °F step. A "10-degree" forecast difference is 18 °F, not 10 °F. This is why a 5 °C day feels very different from a 15 °C day.
Negative signs
Below freezing, (°F − 32) is negative; keep the sign through the whole calculation. −40 °C = −40 °F is the only point where the two scales meet.
A unit-conversion reference site has no manufacturer-specific or device calibration parameters, so "layered tuning" does not apply here. The only real error-handling is input validation: the converter rejects non-numeric, empty, or out-of-range entries and shows a clear message, then falls back to exact constants above. No estimated or rounded figures are ever presented as exact.
Authoritative sources for this page
- NIST (U.S. National Institute of Standards and Technology) — NIST — SI Units: Temperature
Last Updated 2026 | This converter was reviewed for accuracy