How it’s worked out
Each drop is cut from the roll; whatever is left over at the end of a roll that’s too short for another drop is wasted, which is why a pattern repeat can add a roll or two.
Drop = height + trim, rounded up to whole repeats Drops = ⌈wall width ÷ roll width⌉ Rolls = ⌈drops ÷ ⌊roll length ÷ drop⌋⌉
An example
14 m of wall, 2.4 m high, standard 53 cm × 10.05 m rolls, 10 cm trim (worked out by this calculator):
| Pattern | Each drop | Drops from a roll | Rolls |
|---|---|---|---|
| Plain | 2.5 m | 4 | 7 |
| 53 cm repeat, straight match | 2.65 m | 3 | 9 |
| 53 cm repeat, half drop | 2.915 m | 3 | 9 |
Tips
- Measure all round the room and add the walls together; don’t take off doors and windows, as the offcuts round them rarely make a full drop.
- Check every roll has the same batch number.
- Buy one spare for mistakes and future repairs.
How to read the result
- Rolls: what to buy, from the drops you can cut from each roll.
- Each drop: the wall height plus trim, rounded up to whole pattern repeats.
- Drops from a roll: where a big repeat costs you.
Common mistakes
- Ignoring the pattern repeat: a big one can add a roll or two.
- Mixing batch numbers: shades differ.
- Taking off every door and window: the offcuts rarely make a full drop.
How to use it
- Type the total width of the walls and their height.
- Type the roll width and length from the label (53 cm × 10.05 m is standard in the UK and Europe).
- Type the pattern repeat and match, then read the rolls.
Questions
How many rolls of wallpaper for a room?
For 14 m of 2.4 m high wall, 7 standard rolls of plain paper, or 9 with a 53 cm repeat.
What is a half-drop match?
The pattern lines up with the next drop half a repeat lower, so each drop starts at a different point and wastes a little more paper.
Do I take off doors and windows?
Usually not: the pieces round them rarely give a whole drop.
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