Paint Calculator — Gallons Needed
Spec no. 09How to use
Enter room length, width and wall height, then the number of doors and windows to subtract (a standard door ≈ 20 sq ft, a window ≈ 15 sq ft). One gallon covers about 375 sq ft per coat (check your can — range is 350–400). Multiply by your number of coats, typically 2.