Celsius & Fahrenheit: Formulas and Quick Estimates
F to C: ℃ = (℉ − 32) × 5/9; C to F: ℉ = ℃ × 9/5 + 32. Water freezes at 0℃/32℉ and boils at 100℃/212℉.
Three scales
- Celsius: everyday and scientific use
- Fahrenheit: US weather and cooking
- Kelvin: starts at absolute zero, used in physics/chemistry
Quick-trick estimates
Doubling Celsius and adding 30 ≈ Fahrenheit (e.g., 20℃→70℉, actual 68℉) — good for estimates.
💡 When reading overseas weather or baking recipes, a temperature converter showing all three scales saves the most hassle.