Home Improvement
Wallpaper calculator
Wallpaper punishes two mistakes equally: one roll short, and rolls from different dye lots. This calculator works from the room's wall area — perimeter × height, minus doors and windows — then adds a pattern-waste allowance for the material that disappears into matching repeats and trim cuts. Rolls come from your roll's actual usable coverage, not its nominal size, and the dye-lot note is there before you order, not after the seams show.
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Smoothing & hanging kitRolls counted — smooth out the bubbles as each sheet goes up.Check current price ↗As an Amazon Associate, CalcForged earns from qualifying purchases.The math, plainly
How it works
- 01
Wall area is the room perimeter × wall height, minus 21 square feet per door and 15 per window.
- 02
Pattern waste — 15% is typical — covers matching repeats and trimming; large patterns and many corners need more.
- 03
Rolls are order area ÷ coverage per roll, rounded up. A US double roll is 60.75 sq ft nominal but lands near 55 usable.
Try a real scenario
12 × 14 room
Inputs8 ft walls, 1 door, 2 windows, 15% pattern waste
Result365 sq ft of wall — 8 rolls at 55 sq ft each, about $240.
Gear for the job
Tools & materials people actually buy
Smoothing & hanging kit
Smooths out bubbles and air pockets as you hang — the difference between flat and foamy.
Wallpaper paste
The right paste for your paper weight, mixed fresh — old buckets fail at the seams.
Seam roller
One light pass on each seam presses the edge down before the paste sets.
Snap-off knife
A fresh blade every couple of panels tears nothing and drags nothing.
As an Amazon Associate, CalcForged earns from qualifying purchases made through these links.