Paint, Drywall & Wall Calculators

Finishing a wall is three estimates in a row — sheets to hang, mud and tape to hide the joints, then gallons or rolls to cover the lot — and each has its own trap. Drywall is bought by the sheet but wasted by the cut. Paint coverage on the can assumes a sealed, smooth surface you rarely have. Wallpaper looks simple until a 24-inch pattern repeat turns each roll into fewer usable strips than the label suggests.

These calculators deal with each trap explicitly. The drywall tool deducts standard door and window areas (21 and 15 square feet) and adds 10% for cuts as a visible line item. The paint tool lets you set real-world coverage between 250 and 400 square feet per gallon instead of accepting the optimistic number on the label. The wallpaper tool does the strip-and-drop math that causes most short orders.

Measure the room once — length, width, height — and you can run all three tools with the same numbers. Every page shows its formula and a worked example, so you can check the math against your own room rather than take a black box’s word for it.