Celsius to Fahrenheit
Convert Celsius to Fahrenheit instantly. Free temperature converter, no signup.
How to use this tool
- Enter degrees celsius in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your degrees fahrenheit and the full breakdown beneath it.
Convert Celsius to Fahrenheit instantly. Free temperature converter, no signup.
Formula
°F = (°C × 9/5) + 32
Multiply the Celsius temperature by 9, divide by 5, then add 32. This accounts for both the different scale size (9/5 ratio) and the offset between the two scales' zero points (32°F = 0°C).
How it works
To convert Celsius to Fahrenheit, multiply the Celsius value by 9/5 (= 1.8) and then add 32. The factor 9/5 accounts for the fact that a Fahrenheit degree is smaller than a Celsius degree (there are 180°F between freezing and boiling versus 100°C), and the +32 shifts the zero point, since water freezes at 0°C but 32°F. Both operations are required; omitting either gives a wrong answer.
Common mistake: Forgetting to add 32 after multiplying, or applying the addition before the multiplication. Order of operations matters here: multiply first, then add the 32-degree offset.
Worked example
Convert 100°C (boiling point of water) to Fahrenheit
- Start with the input: 100°C.
- Multiply by 9/5: 100 × 1.8 = 180.
- Add the zero-point offset: 180 + 32 = 212.
- Result: 212°F — the boiling point of water at sea level.
100°C = 212°F
Common mistakes to avoid
- Adding 32 before multiplying by 9/5 instead of multiplying first — converting 20 C incorrectly as (20+32)x9/5 = 93.6 F instead of the correct 68 F.
- Using 9/5 = 1.8 but forgetting the +32 offset, giving a scale-matched but zero-shifted result.
- Confusing the formula with the Kelvin conversion and adding 273 instead of 32.
Key terms
- Celsius (°C)
- A temperature scale where 0°C is the freezing point of water and 100°C is its boiling point at standard atmospheric pressure. The official SI-derived scale used in most of the world.
- Fahrenheit (°F)
- A temperature scale used primarily in the United States, where water freezes at 32°F and boils at 212°F at standard pressure.
- Absolute Zero
- The lowest possible temperature, −273.15°C (−459.67°F), at which all thermal motion ceases. It defines the zero point of the Kelvin scale.
- Scale Offset
- The difference in zero-point definition between two temperature scales. Between Celsius and Fahrenheit the offset is 32°F, which must be added or subtracted in every conversion.
Frequently asked questions
- What is 100 C in Fahrenheit?
- 100 C = (100 x 9/5) + 32 = 212 F, the boiling point of water at sea level.
- At what temperature are Celsius and Fahrenheit equal?
- At -40 degrees: -40 C = -40 F. That is the only crossover point of the two scales.
- Is body temperature 37 C or 98.6 F?
- Both — 37 C x 9/5 + 32 = 98.6 F. Normal body temperature is the same value expressed in different units.