100 degrees Fahrenheit is equal to 37.7778 degrees Celsius.
To convert 100°F to Celsius, you subtract 32 from the Fahrenheit value, then multiply the result by 5/9. This formula adjusts for the difference in zero points and scales between the two temperature units.
Conversion Tool
Result in c:
Conversion Formula
The formula to convert Fahrenheit (f) to Celsius (c) is:
C = (F – 32) × 5/9
This formula works because the Fahrenheit scale starts 32 degrees higher than Celsius at the freezing point of water, and each degree Fahrenheit is 5/9 the size of one degree Celsius. Subtracting 32 adjusts the starting point, and multiplying by 5/9 scales the value to Celsius units.
Example calculation for 100°F:
- Start with 100°F.
- Subtract 32: 100 – 32 = 68.
- Multiply by 5/9: 68 × 5/9 = 68 × 0.5556 ≈ 37.7778.
- So, 100°F ≈ 37.7778°C.
Conversion Example
- Convert 50°F to Celsius:
- Subtract 32: 50 – 32 = 18.
- Multiply by 5/9: 18 × 5/9 = 10.
- Result: 50°F = 10°C.
- Convert 212°F to Celsius:
- Subtract 32: 212 – 32 = 180.
- Multiply by 5/9: 180 × 5/9 = 100.
- Result: 212°F = 100°C.
- Convert 32°F to Celsius:
- Subtract 32: 32 – 32 = 0.
- Multiply by 5/9: 0 × 5/9 = 0.
- Result: 32°F = 0°C.
- Convert 68°F to Celsius:
- Subtract 32: 68 – 32 = 36.
- Multiply by 5/9: 36 × 5/9 = 20.
- Result: 68°F = 20°C.
Conversion Chart
The table below shows Fahrenheit temperatures from 75.0°F to 125.0°F, converted to Celsius. This chart helps you quickly find the Celsius equivalent without calculation. Simply find the Fahrenheit value in the left column and read across the Celsius result.
| Fahrenheit (°F) | Celsius (°C) |
|---|---|
| 75.0 | 23.8889 |
| 80.0 | 26.6667 |
| 85.0 | 29.4444 |
| 90.0 | 32.2222 |
| 95.0 | 35.0000 |
| 100.0 | 37.7778 |
| 105.0 | 40.5556 |
| 110.0 | 43.3333 |
| 115.0 | 46.1111 |
| 120.0 | 48.8889 |
| 125.0 | 51.6667 |
Related Conversion Questions
- What is 100 Fahrenheit in Celsius with decimal accuracy?
- How to convert 100°F temperature to Celsius manually?
- Is 100 degrees Fahrenheit hot or cold in Celsius scale?
- Why subtract 32 when converting 100°F to Celsius?
- What formula to use for changing 100°F to Celsius?
- How much Celsius equals to 100 degrees Fahrenheit?
- How do I calculate 100°F into Celsius using a calculator?
Conversion Definitions
F (Fahrenheit): Fahrenheit is a temperature scale used primarily in the United States and some Caribbean countries. Its zero point is based on a mixture of ice, water, and salt, while the boiling point of water is set at 212 degrees. Each degree Fahrenheit represents 1/180th of the temperature difference between freezing and boiling water.
C (Celsius): Celsius is a temperature scale used worldwide, based on the freezing and boiling points of water at standard atmospheric pressure. Zero degrees Celsius is the freezing point of water, and 100 degrees Celsius is the boiling point. Each degree Celsius is equal in size to one Kelvin unit.
Conversion FAQs
Why do we subtract 32 when converting from Fahrenheit to Celsius?
The Fahrenheit scale sets the freezing point of water at 32 degrees, unlike Celsius which starts at zero. So subtracting 32 removes the offset between the two scales before adjusting for the degree size difference by multiplying by 5/9.
Can this conversion formula be reversed to convert Celsius to Fahrenheit?
Yes, to convert Celsius to Fahrenheit, you reverse the process by multiplying the Celsius temperature by 9/5 and then adding 32. The formula is F = (C × 9/5) + 32.
Is the conversion exact or approximate?
The conversion is exact based on the defined scaling of the two temperature scales. However, decimals may be rounded when displayed, causing slight approximations in the numeric result.
Why use 5/9 in the conversion formula?
Because each Fahrenheit degree is 5/9 the size of a Celsius degree. Multiplying by 5/9 scales the temperature difference correctly from Fahrenheit units to Celsius units.
What happens if I forget to subtract 32 first?
If you skip subtracting 32, the conversion will be wrong because the offset between the freezing points of the two scales is ignored. The result will be higher than the actual Celsius temperature.
Last Updated : 12 July, 2025
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Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.