Whole-room planner

Most calculators do one thing. This one plans the room: paint for walls, ceiling and trim, an accent wall of wallpaper, the biggest rug that leaves a neat border, and curtains for every window, in one list you can print or copy.

How it works

• Paint: wall area is the room’s perimeter times the ceiling height, minus about 21 sq ft per door and 15 sq ft per window. Ceilings are length times width. Trim is estimated from the baseboard plus door and window casings. We use 350 sq ft per gallon per coat, the low end of the 350 to 400 the big paint makers publish, and round up to whole quarts and gallons.
• Accent wall: the longest wall, in standard 20.5 in by 33 ft double rolls, plus 15% for matching the pattern.
• Rug: the largest standard size that leaves 18 inches of floor showing on every side.
• Curtains: a rod 8 inches wider than the window on each side, panels for 2x fullness and a standard length for your ceiling.

Each part links to its own calculator if you want more control, for example a pattern repeat, a dining table or puddled curtains.

Sources

• Sherwin-Williams paint calculator: a gallon covers about 350 to 400 sq ft; a quart about 100 sq ft; a gallon of primer 200 to 300 sq ft
• Magnolia Home wallpaper (York): double roll 20.5 in x 33 ft = 56 sq ft
• Room & Board: how to choose a rug size (24 in around a dining table; 18 in to the wall)
• Wayfair: how to measure for curtains (rod 4 to 6 in above the frame; 84 in panels for 8 ft ceilings)
• The Home Depot: measuring for window curtains (2 to 2.5 times the window width; sheers 3 times)

Sources last checked 1 November 2026.