Calculate exactly how much paint you need for any room. Enter dimensions, doors, windows, and coverage to get gallons required with waste factor. Free online tool.
This free online paint calculator helps you estimate exactly how much paint you need for your room or project. Simply enter your room dimensions, the number of doors and windows, your paint coverage rate, and the number of coats. The calculator accounts for waste factor and rounds up to whole gallons or liters so you know how much to buy.
The calculator provides a close estimate based on standard dimensions. Actual paint needs may vary depending on surface texture, paint quality, and application method. Always round up and buy a little extra for touch-ups.
Waste factor accounts for paint lost to spills, brush cleaning, uneven application, and leftover paint in the can. We offer Low (10%), Medium (15%), and High (20%) options to match your project type.
Most walls need 2 coats for even coverage — one primer/base coat and one finish coat. Dark colors, porous surfaces, or dramatic color changes may require 3 coats.
Yes! Simply enter your ceiling dimensions as length × width (with height set to 0 or ignored) and set the number of coats. The calculator treats all surfaces the same way.