try a colour on the walls

Walls: Terracotta example colours, not products

This room: 12 × 12 ft, 8 ft walls, one door and two windows · 2 coats · 350 sq ft per gallon on the can

2 gallons + 1 quart337 sq ft × 2 coats + 10% ÷ 350 = 2.12 gal, rounded up to cans

Calculate your room

Measure the room, read the label, buy the right number of cans, rolls and boxes.

Three calculators for interior paint, wallpaper and flooring. Each one shows its arithmetic and rounds up to the packages you can actually buy.

An open can of terracotta paint, a roller in a tray and a tape measure on a drop clothInterior paintcans and quartsPaint calculatorTurn your room measurements into a paint shopping list.Two wallpaper rolls standing on a wooden floor, a third roll unrolled to show a leaf pattern, with a smoothing brushWallpaper rollsrolls and packsWallpaper calculatorTurn one wall and your roll label into the number of rolls to buy.A floor half covered with oak planks, an open carton of planks and a pull bar at the seamFlooring boxesboxesFlooring calculatorTurn floor measurements and the carton label into whole boxes to buy.

Guides

Worked examples and label-reading notes, checked against manufacturer pages.

A small bedroom seen from the doorway, furniture covered by a drop cloth, walls half painted terracottaA 12-by-12 bedroom, two coats: the paint math by hand, and the three places it slips2026-09-09 · Paint calculatorTwo hands turning a paint can to read the back of its label in a hardware store aisleHow to read paint coverage before you buyReference guideTwo wallpaper rolls of different lengths unrolled side by side on a floor with a tape measureSingle roll, double roll, pack: what you are actually buyingReference guideA plank floor nearly finished, a pile of offcuts in the corner, an open carton and a saw on a sawhorseAllowance vs whole-box rounding: keep them apartReference guideAn open notebook with a pencil sketch of a room outline, a tape measure and a small paint can on a workbenchHow Wall Math calculates your materialsReference guideTwo hands stretching a tape measure along a baseboard toward a door frameHow to measure a room for paint, wallpaper and flooringReference guide

All guides

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