Wallpaper Calculator
Calculate wallpaper rolls from room dimensions, roll size and pattern repeat. Deduct doors and windows and add matching waste.
Wallpaper rolls needed
79
- Wall area
- 329 sq ft
- Coverage per roll
- 4.7 sq ft
- Pattern repeat
- 0 in
- Rolls with matching allowance
- 79
- Estimated wallpaper cost
- $3,555.00
Assumes a 1.7 in wide × 33 ft roll and a 10% waste allowance. Large pattern repeats and walls with many openings need an extra roll.
Wallpaper is sold in rolls, but the usable coverage depends on the roll width, the wall height and the pattern repeat. A large repeat can waste most of a roll, which is why area alone is not enough.
This calculator starts with the wall area, deducts standard openings, and adds an allowance for pattern matching. Buy all rolls in one order so the dye lot matches, and keep one spare for repairs.
How the wallpaper calculator works
Wall area = 2 × (length + width) × height − 21 sq ft per door − 15 sq ft per window. Usable coverage per roll = roll width × roll length. Base rolls = wall area ÷ coverage. Pattern matching adds a penalty of 1 + (repeat ÷ wall height). Rolls = base rolls × penalty × (1 + waste), rounded up.
Worked example
A 12 × 14 ft room with an 8 ft ceiling has 416 sq ft of wall. Two doors and three windows remove 87 sq ft, leaving 329 sq ft. A 20.5 in × 33 ft roll covers about 56 sq ft, so with 10% waste you need 7 rolls.
Pattern repeat and roll count
The pattern repeat is the distance before the design lines up again. A 24-inch repeat on an 8 ft wall means each strip may need extra length to match the next strip, and that offcut usually cannot be used.
Random-match and free-match patterns waste little. Straight-match patterns are the most wasteful; drop-match patterns waste less but need careful sequencing. When in doubt, buy one extra roll and keep it unopened.
Wall preparation
- Remove old wallpaper and adhesive residue; new paper will not stick to either.
- Patch holes, sand the patches, and prime bare drywall or repair compound.
- Use a wallpaper sizing or primer recommended by the manufacturer.
- Turn off power to outlets and remove cover plates before hanging.
- Book the strips for a few minutes so the paper relaxes before it goes on the wall.
Wallpaper types
| Type | Installation | Best for |
|---|---|---|
| Unpasted | Apply paste to the wall or paper | Traditional and grasscloth |
| Pre-pasted | Water-activate the backing | Easy DIY rooms |
| Peel-and-stick | Remove backing and press | Rentals and accent walls |
| Grasscloth | Professional paste and booking | Texture; humidity-sensitive |
| Mural | Custom panels | Feature walls |
Frequently asked questions
How many rolls of wallpaper for a 12 × 12 room?
With 8 ft walls, two doors and two windows, the wall area is about 312 sq ft. At 56 sq ft per double roll and 10% waste, buy 7 rolls.
What is a pattern repeat?
The distance between repeating design elements, measured vertically. A 24-inch repeat means strips must be shifted to match, which increases waste.
Should I subtract doors and windows?
Yes for a realistic estimate, using about 21 sq ft per door and 15 sq ft per window. Keep a spare roll anyway for patches and future repairs.
How many square feet does a roll of wallpaper cover?
A U.S. double roll of 20.5 in × 33 ft covers about 56 sq ft. Single rolls and European rolls vary, so check the label before calculating.
Can I hang wallpaper over existing wallpaper?
Not recommended. Old paper can bubble, trap moisture and pull away, taking the new layer with it. Remove it and prepare the wall first.
How long does wallpaper last?
A well-installed wallpaper can last 10–15 years or more. Bathrooms and kitchens need moisture-resistant products and good ventilation.
Assumptions and accuracy
- Dimensions are converted to feet before the calculation; 1 ft = 12 in = 0.3048 m.
- Waste allowances are estimates. Add more for irregular shapes, many cuts and uneven subgrade.
- Bag yields, coverage rates and material densities vary by product. Check the label or ask your supplier.
- Local building codes and site conditions always take precedence over a general-purpose calculator.
- Read our full methodology