How to Calculate Wallpaper Quantities

Our instructions on how to calculate wallpaper quantities will prevent you from running out and will help you to reduce waste. Easy to follow, our step-by-step guide will clearly take you through each stage. You will need a paper and pen, plus 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.

Example:

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

If you have walls of the same heights you can add the widths together. If all your walls are different heights you will need to calculate each one individually.

Example:

• Walls (A) and (B) are the same height so can be combined – 330cm x 220cm
• Wall (C) 110cm x 180cm

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

Example:

Using a 52cm wallpaper width

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

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

Example:

• 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 head straight on to step 6. Otherwise, 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:

Using a 38cm pattern repeat.

• 7 + 3 drops = 10 drops
• 10 drops – 1 = 9 pattern repeats required
• 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.

Example:

• 342cm total pattern repeat / 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 Wall (A&B) width + 540cm Wall (C) width + 342cm pattern repeat = 2422cm
• 2422cm / 1000cm (10 metres) = 2.422. You can’t buy part rolls, so always round this up
• Total requirement = 3 rolls

Now you know how many rolls you need, all that remains is to place your order...