How to Calculate Wallpaper Quantities

Make sure you know the width of your chosen designer wallpaper, the length of the roll, and the pattern repeat (if the wallpaper has one).

First, you will need to measure each wall that you want to paper. Measure the width and the height in centimetres. If the walls have the same heights you can add the widths together, if not you will need to work out one wall at a time.

Example:

Wall (A) 150cm width x 220cm height.
Wall (B) 180cm width x 220cm height.
Wall (C) 110cm width x 180cm height.

This instance works out two wall spaces. There's walls (A) and (B) 330 cm x 220 cm, and wall (C) 110 cm x 180 cm.

You can now divide your wall widths by your wallpaper width to work out how many drops you need.

Example:

Wall A&B) 330cm / 52cm = 6.34. Always round up = 7 drops.
Wall C) 110cm / 52cm = 2.11 round up = 3 drops.

Next you will need to multiply the number of drops by the wall height.

Wall A & B: 7 drops x 220cm height = 1540cm.
Wall C: 3 drops x 180cm height = 540cm.

If you are using wallpaper that has no vertical pattern repeat, you can skip to number 5).

If you have a wallpaper with a pattern repeat, there is still a little more work to do!

To work out the pattern repeat allowance, you need to add a pattern repeat for each drop, apart from the first one.

Example:

7 + 3 drops = 10.
10 drops – 1 = 9 pattern repeats.
9 x 38cm pattern repeat = 342cm.

If your design has a half drop then you need to add half of your total pattern repeat again.

For example: 342cm / 2 = 171cm.

342cm + 171cm = 513cm.

Add your totals together which will tell you the total meterage you require to cover your walls. Divide this by the roll length to work out how many rolls you need.

Example: 
1540cm + 540cm + 342cm = 2422cm.
2422cm / 1000cm (10 metres) = 2.422. You can’t buy part rolls, so round this up to 3 rolls.