What you need to know
- Calculate the number of vertical drops needed around the room.
- Adjust drop length for the pattern repeat.
- Work out how many complete drops come from each roll and round up.
Use your own measurements
Use the linked BricoDato resource to check these inputs in your own situation. Wallpaper coverage is determined by the number of full-height drops obtainable from each roll.
Why area alone can mislead
Wallpaper is installed in full vertical drops. A door or window reduces area but may not eliminate a complete drop from the layout.
Account for the pattern repeat
A repeating design can force each cut to be longer than the wall height. The larger the repeat, the fewer usable drops you may get from each roll.
Use actual roll dimensions
Check roll width and length on the product label. Do not assume every wallpaper roll is the same size.
Buy the same batch
Colour can vary slightly between production lots. Buy enough at once and keep a spare length for future repairs.
Count usable strips rather than area alone
Wallpaper coverage is determined by the number of full-height drops obtainable from each roll. Pattern matching and trimmed ends can change that number even though wall area is unchanged.
Example to adapt
Imagine a 4 m-wide wall, 2.5 m high, with paper 0.53 m wide. You need ceil(4 ÷ 0.53) = 8 strips. If a 10 m roll allows a 2.7 m cutting length (including a small trim allowance), you obtain floor(10 ÷ 2.7) = 3 strips per roll, so 3 rolls. If matching a larger pattern forces a 3.4 m drop, only 2 strips fit per roll and the same wall needs 4 rolls.
| Usable drop length | Strips per 10 m roll | Rolls for eight strips |
|---|---|---|
| 2.5 m | 4 | 2 |
| 2.7 m | 3 | 3 |
| 3.4 m | 2 | 4 |
Checks before acting
- Confirm actual roll length and width before calculating strip yield.
- Calculate the exact pattern repeat and match type from the label.
- Include over-door and corner sections without assuming every offcut is reusable.
- Order the same batch and check the shop's unopened-roll return policy.
Final check
Roll count depends on vertical drops and pattern alignment, not just square metres. For a 3.8 m-wide wall with 2.5 m height, a hypothetical 0.53 m-wide roll needs eight drops. If trimming raises the drop to 2.6 m, a 10 m roll supplies only three plain drops, so at least three rolls are needed even before accounting for a pattern repeat.
- Confirm roll width and length.
- Check the pattern repeat and match type.
- Round to complete rolls.
- Buy the same batch / dye lot.
Keep a small job sheet
Save ceiling height, wall widths, roll size, match/repeat, cuts per roll and batch number.
Turn the guide into a decision
Measure the actual floor-to-ceiling height at several points and include the declared pattern repeat. Confirm identical dye lots and adhesive compatibility; a calculator based only on the wall's area can understate material for large patterned designs.