Wallpaper Calculator
Estimate wallpaper rolls from wall width, drop height, roll size and pattern repeat.
Last reviewed September 19, 2026
Result
Enter total wall width to see the result.
https://calcgallery.com/paint-drywall/wallpaper-calculator/
Results are estimates for planning only. Actual needs vary with site conditions, products and workmanship. Always confirm quantities with your supplier and follow local building codes and manufacturer instructions. Read the full disclaimer
How to use it
- Add the widths of every wall to be papered and enter that total.
- Enter the wall height and the usable roll width and length from the label.
- Enter the vertical pattern repeat, or zero for a free match or plain paper.
- Read the full rolls required from the calculated number of drops.
How it is calculated
Wallpaper is bought as full drops, not just by square area:
Drop length = ceil(wall height ÷ repeat) × repeat
Drops needed = ceil(total wall width ÷ roll width)
Rolls = ceil(drops needed ÷ full drops per roll)When the repeat is zero, the wall height is used directly as the drop length. The calculator then fits only whole drops into each roll.
Before ordering
Use the label dimensions. Nominal and usable widths can differ, and some products are sold as double rolls. Enter the physical roll you will receive.
Keep one batch number. Colour can shift between production batches. Order the job together and consider a spare roll for repairs.
Allow for trimming. Installers normally cut a little beyond the ceiling and skirting. If that trimming allowance is material for a tight roll layout, add it to the entered wall height.
Treat complex matches separately. Offset, half-drop and large mural panels need the manufacturer’s layout rather than this straight-repeat calculation.
With your numbers
- Drop length = 8 ft after allowing for a 0 in repeat
- 24 drops are needed and each roll yields 4
- Drops needed ÷ drops per roll, rounded up to 6 rolls
Quick reference
The pattern repeat is included in every drop. Add a spare roll manually for offset matching, damage or future repairs.
| Job | Wallpaper rolls to buy |
|---|---|
| 40 ft wide, 8 ft high, no repeat | 6 |
| 40 ft wide, 8 ft high, 21 in repeat | 8 |
| 30 ft wide, 8 ft high | 5 |
| 50 ft wide, 9 ft high | 10 |
| 10 m wide, 2.4 m high | 5 |
| 12 m wide, 2.5 m high, 64 cm repeat | 8 |
Common questions
- How many wallpaper rolls for 40 feet of wall?
- At 8 ft high with 20.5 in × 33 ft rolls, 24 drops are needed. Four drops fit a roll with no repeat, so the result is 6 rolls.
- Why does pattern repeat increase the roll count?
- Every drop must start at a matching point. Its cut length is rounded up to a whole repeat, which can reduce how many full drops fit on one roll.
- Should I subtract doors and windows?
- Usually not from the drop count. Full drops are still cut across most openings, and their offcuts are not guaranteed to fit elsewhere.
- Does this handle half-drop matching?
- No. Offset and half-drop patterns can require additional material. Check the label or installer’s layout and add spare rolls manually.