Paint, Drywall & Wallpaper Calculators
Turn room dimensions into practical shopping quantities. PlanDIYBuild calculates wall area, deducts common openings, applies coats or waste, and visualizes the room surfaces being measured.
One room, three material takeoffs
Use the tool that matches your project. Each calculator uses the same basic room geometry so you can move from drywall to paint or wallpaper without changing how you measure.
Paint Calculator
Deduct doors and windows, apply coats and coverage, and estimate gallons and cans.
Calculate →Drywall Calculator
Estimate drywall sheets, screws, joint compound and tape from room dimensions.
Calculate →Wallpaper Calculator
Estimate net wall area, pattern allowance and whole wallpaper rolls.
Calculate →Wall project reference guides
Start with common-room tables for a fast estimate, then use the calculator for your exact dimensions, openings and product coverage.
Perimeter × height is the starting point
For a rectangular room, wall area begins with twice the room length plus twice the room width, multiplied by wall height. PlanDIYBuild then deducts approximate door and window areas before applying coats, waste, pattern allowance or sheet coverage. Verify product-specific coverage and installation requirements before purchasing.