Wallpaper Calculator — How Much Wallpaper Do I Need?
Enter your room size, ceiling height, doors and windows to get the exact number of wallpaper rolls. No sign-up, no data stored.
Wallpaper rolls needed
How wallpaper quantity is calculated
The math is simple and exact — no assumptions to adjust for:
- Wall area = perimeter (2 × (length + width)) × ceiling height.
- Openings = doors (≈21 sq ft each) + windows (≈15 sq ft each), subtracted so you don't over-order.
- With pattern = net area × (1 + pattern waste%).
- Rolls = area ÷ roll coverage, rounded up.
A standard double roll covers about 56 sq ft. Patterned wallpaper needs more because you trim the excess to line up the repeat at each seam — the bigger the repeat, the more waste.
Wallpaper coverage chart
Roll coverage and how much extra to allow for pattern matching.
Roll size → coverage
| Roll type | Coverage |
|---|---|
| Single roll | ~28 sq ft |
| Double roll (standard) | ~56 sq ft |
| Double roll (large) | ~60 sq ft |
Pattern waste
| Pattern | Add for waste |
|---|---|
| Solid / no match | ~5% |
| Small repeat | ~10% |
| Medium repeat | ~15% |
| Large / busy repeat | ~20–25% |
Last updated: October 2026 · Roll coverage is typical for US wallpaper. Door and window areas are typical values; measure yours for exact results. Always confirm roll size and pattern repeat with the manufacturer.
Wallpaper calculator FAQ
Walls are 384 sq ft (48 ft perimeter × 8 ft). Minus one door (21) and one window (15) = 348 sq ft. Add 10% pattern = 383 sq ft, which is about 7 double rolls.
Most wallpaper is sold in double rolls, though priced per single roll. A double roll is one continuous 20.5×33 ft piece, and you pay the price of two singles. Always confirm how your supplier labels it.
For a clean, professional finish, wallpaper the entire wall even behind furniture — it's easier to move furniture than to patch wallpaper later, and it looks better if you rearrange.
Each strip must be cut longer than the wall so the pattern lines up at the ceiling and at every seam, then the excess is trimmed. A large repeat can waste 20% or more of each roll.
Yes. Order one extra double roll if the pattern is busy or the dye lot is important — wallpaper can be hard to match later, and a different batch may not match exactly.