What is Paint?
The Paint Calculator estimates how much paint you need for a room based on wall dimensions, minus doors and windows. One liter of paint typically covers 100-120 sq ft (one coat). Most rooms need 2 coats for even coverage.
This saves money by avoiding over-purchasing and prevents the frustration of running short mid-project.
Formula
Wall Area = 2 × (Length + Width) × Height Door Area = doors × 21 sq ft (standard) Window Area = windows × 15 sq ft (standard) Paintable Area = (Wall Area − Door − Window) × Coats Paint (liters) = Paintable Area / 110 Paint (gallons) = Paintable Area / 400 Coverage per liter: ~100-120 sq ft Coverage per gallon: ~350-400 sq ft
How to use this Paint Calculator?
1. Enter room length, width, and wall height. 2. Set number of coats (2 is standard). 3. Enter number of doors and windows (auto-deducted). 4. See paint needed in liters and gallons.