Celsius and Fahrenheit are temperature scales with different zero points and degree sizes. Use this converter for weather, cooking, study, travel, and other everyday temperature conversions. It supports decimal and negative values in both directions.
Celsius to Fahrenheit Formula
Formula: °F = (°C × 9/5) + 32
Multiply the Celsius value by 9/5, then add 32.
For example, 20°C multiplied by 9/5 equals 36. Add 32, and the final result is 68°F.
Fahrenheit to Celsius Formula
Formula: °C = (°F − 32) × 5/9
Subtract 32 from the Fahrenheit value, then multiply by 5/9.
Worked Temperature Conversion Examples
Example 1: Convert 25°C to Fahrenheit
Use °F = (°C × 9/5) + 32.
- 25 × 9/5 = 45
- 45 + 32 = 77
Answer: 25°C = 77°F
Example 2: Convert 77°F to Celsius
Use °C = (°F − 32) × 5/9.
- 77 − 32 = 45
- 45 × 5/9 = 25
Answer: 77°F = 25°C
Example 3: Convert a Negative Temperature
For −15°C:
(−15 × 9/5) + 32 = −27 + 32 = 5°F
Answer: −15°C = 5°F
Celsius to Fahrenheit Conversion Chart
Use this table for common weather, room, cooking, and reference temperatures. Exact mathematical values are shown; household ovens may use nearby standard settings.
| Celsius (°C) | Fahrenheit (°F) | Common reference |
|---|---|---|
| −40°C | −40°F | Both scales show the same number |
| −20°C | −4°F | Very cold winter weather |
| −10°C | 14°F | Freezing weather |
| 0°C | 32°F | Water freezes at standard pressure |
| 10°C | 50°F | Cool outdoor temperature |
| 20°C | 68°F | Comfortable room reference |
| 25°C | 77°F | Warm day |
| 30°C | 86°F | Hot weather |
| 37°C | 98.6°F | Common body-temperature reference |
| 40°C | 104°F | Very hot temperature |
| 100°C | 212°F | Water boils at standard pressure |
| 150°C | 302°F | Low oven setting |
| 180°C | 356°F | Often treated as about 350°F in recipes |
| 200°C | 392°F | Often treated as about 400°F in recipes |
| 230°C | 446°F | Often treated as about 450°F in recipes |
Common Conversion Mistakes
- Forgetting the 32: Multiplying alone does not complete the conversion because the scales have different zero points.
- Using the wrong order: For Fahrenheit to Celsius, subtract 32 before multiplying by 5/9.
- Rounding too early: Keep the full value until the final step, then round once.
- Confusing exact and practical oven values: 180°C is exactly 356°F, but many recipes use the nearby standard oven setting of 350°F.
How to Verify a Temperature Conversion
Use the reverse formula to convert the answer back to the original scale.
Example: 20°C = 68°F. Check it with the reverse formula:
(68 − 32) × 5/9 = 20°C
Celsius and Fahrenheit Reference Points
- Absolute zero: −273.15°C = −459.67°F
- Equal point: −40°C = −40°F
- Water freezes: 0°C = 32°F at standard atmospheric pressure
- Water boils: 100°C = 212°F at standard atmospheric pressure
- Scale interval: A change of 5°C equals a change of 9°F
Frequently Asked Questions
The formula is °F = (°C × 9/5) + 32. Multiply the Celsius temperature by 1.8, then add 32.
The formula is °C = (°F − 32) × 5/9. Subtract 32 first, then multiply by 5/9.
The two scales have the same numerical value at −40 degrees: −40°C equals −40°F.
Yes. Negative temperatures use the same formulas as positive values. For example, −10°C equals 14°F.
Yes. Enter a value such as 36.5°C or 98.6°F and select the decimal precision you need.
The exact conversion is 356°F. A household recipe may use a nearby standard setting, commonly 350°F, depending on the oven.
The scales use different zero points and degree intervals. Water freezes at 0°C and 32°F, while it boils at 100°C and 212°F at standard atmospheric pressure.
How We Calculate
Calculations use the standard formulas °F = (°C × 9/5) + 32 and °C = (°F − 32) × 5/9. The calculator keeps the full mathematical value before applying the selected display precision. Values below absolute zero are rejected as physically impossible.
Last reviewed: July 26, 2026
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