Celsius to Fahrenheit
Celsius to Fahrenheit in Depth
The formula: °F = °C × 9/5 + 32. Two anchor points make it intuitive — 0°C = 32°F (freezing) and 100°C = 212°F (boiling) — and everything else interpolates linearly between them.
Mental Math That Works
Double the Celsius, subtract 10%, add 32: 20°C → 40 − 4 + 32 = 68°F, exact. For weather, memorizing the 10-degree ladder (0°→32°, 10°→50°, 20°→68°, 30°→86°) covers every forecast you will ever read.
Where It Matters
Travel (US weather reports), cooking (American recipes list °F), and science classes bridging metric labs with imperial datasets. Medical: 37°C = 98.6°F is the reference; a "fever" threshold converts with it.
How to Use the Celsius to Fahrenheit Converter
This converter turns Celsius temperatures into Fahrenheit, which helps when you read a metric recipe, a foreign weather report, or a science value and think in the US scale.
- Enter the Celsius temperature from your source.
- The tool applies the formula °F = (°C × 9/5) + 32.
- Read the Fahrenheit result and carry on.
Example
Enter 100 °C, the boiling point of water, and you get 212 °F. A pleasant 20 °C day converts to 68 °F, and −40 °C is the fun crossover point where both scales read −40.
Frequently Asked Questions
Why multiply by 9/5?
A Fahrenheit degree is smaller than a Celsius degree: 180 Fahrenheit degrees span the same range as 100 Celsius degrees between freezing and boiling, and 180/100 simplifies to 9/5.
What is the quick mental version?
Double the Celsius value and add 30. So 25 °C becomes roughly 80 °F, near the exact 77 °F — good enough for weather chat.
Does the formula work below zero?
Yes, it handles negatives cleanly. For example, −10 °C converts to 14 °F. Just enter the minus sign along with your number.