Guides
Wallpaper repeat, match and batch
Read matching symbols, calculate complete drops and verify roll yield and batches before cutting.
Wallpaper is bought by roll but cut into drops that fit height and pattern. Dividing wall area by roll area may understate purchasing. Read matching symbols first and check how many complete drops can actually be cut.
Key points
- Width determines drop count; height and trimming determine drop length.
- Pattern repeat may increase every drop's length.
- The tool does not plan offset matching or cutting around openings.
In this guide
Prepare your inputs
- Surface width and greatest modeled height.
- Roll width, length and matching symbols.
- Combined top-and-bottom trimming length, product and batch numbers.
1. Read matching symbols
Distinguish free, straight and offset matching. Straight matching aligns adjacent patterns at the same level. Offset matching requires the stated shift; repeat length alone does not describe its cutting plan.
Check hanging direction and any alternate reversal requirement. Record article, colour and batch for each roll. Manufacturer symbols belong to that exact product, not a visually similar pattern.
2. Determine drop length and count
Add combined top-and-bottom trimming to height. For a regular repeat, the simplified tool rounds this length upward to the next multiple of the pattern step. Use zero step where there is no repeat.
Divide wall width by roll width and round upward. Only complete drops fit a roll, so divide roll length by adjusted drop length and round downward. Different heights and offset matching require a cutting plan that one height field cannot supply.
Drops per roll = floor(roll length / adjusted drop length)
3. Verify the plan before ordering
The calculator applies contingency to drop count, rounds planned drops upward and then rounds rolls upward. Additional drop length and a percentage of extra drops are different inputs; justify both rather than increasing them automatically.
The model neither subtracts doors and windows nor places leftover pieces. An area calculation cannot prove an offcut fits above an opening with the right pattern. Check rolls and batches before cutting and confirm availability and returns with the supplier.
Repeat changes usable roll length
Width 4.2 m, height 2.4 m, combined trimming 0.1 m, roll 0.53 × 10.05 m, regular step 0.64 m and 0% extra-drop allowance.
| Step | Result |
|---|---|
| Drops: ceil(4.2 / 0.53) | 8 |
| Length with trimming | 2.5 m |
| Adjusted: ceil(2.5 / 0.64) × 0.64 | 2.56 m |
| Per roll: floor(10.05 / 2.56) | 3 |
| Rolls: ceil(8 / 3) | 3 |
This model requires 3 rolls. Without matching, a roll supplies 4 complete 2.5 m drops and only 2 rolls are needed. Repeat changes purchasing here. Roll area alone cannot establish usable yield.
This is the model's regular-step example, not a plan for arbitrary offset matching. Inputs are illustrative rather than a product offer.
Try this example in the calculatorCommon mistakes
| Mistake | How to avoid it |
|---|---|
| Dividing wall area by gross roll area. | Count complete drops with matching. |
| Entering centimetres as metres. | 64 cm equals 0.64 m in metric mode. |
| Assuming repeat length handles offset matching. | Plan the shift according to the label. |
Check before using the result
- Height covers the greatest modeled dimension.
- Trimming combines top and bottom.
- Repeat, direction and batches are checked.
Method limits
- The model does not optimize mixed heights, openings or shifts.
- Roll count does not establish substrate preparation or adhesive choice.
Questions and answers
Should I deduct window width?
Only after planning drops and pieces above and below it. The model does not accept openings; verify possible savings in a cutting plan.
What is trimming allowance?
It is additional length per drop, combining top and bottom. It is not a percentage of extra rolls.
Sources and verification scope
- Erismann — wallpaper symbols and explanations
Meaning of free, straight and offset pattern matching and alternate-length reversal. The calculator does not implement every matching instruction.
Access checked: - NIST — SI Units: Length
Length units and the exact inch-to-millimetre relationship. The measuring workflow below is our own practical procedure.
Access checked: