WALLPAPER CALCULATION FORMULA
Wallpaper Calculator
Measure your room wall by wall and enter your dimensions below to estimate how many rolls of wallpaper you may need.
Calculations are based on a standard roll size of 62 cm x 10 m.
We’ve included an allowance for trimming and approximately 15% extra for pattern matching based on a standard room layout. For larger pattern repeats, angled walls or more complex spaces, we recommend consulting your decorator or installer.
Follow the steps below for a manual wallpaper calculation method.
How to Measure for Wallpaper
Step 1: Measure the width of your walls
Measure the width of each wall you plan to wallpaper and add the measurements together to find the total wall width.
We recommend adding approximately 10% extra to allow for trimming, pattern matching and installation variations.
For best accuracy, use a rigid measuring tape and round up to the nearest centimetre.
Step 2: Measure the wall height
Measure the full height of your wall from the skirting board to the ceiling, or to the height you plan to wallpaper.
Again, we recommend allowing a little extra for trimming and installation.
Step 3: Calculate wallpaper quantities
First — Calculate number of drops
Divide total wall width by roll width:
Drops Required=(Wall Width / 0.62)
This tells you how many wallpaper strips (“drops”) are needed.
Next — Calculate adjusted drop height
Because patterns must line up, each wallpaper drop often needs extra length.
Divide wall height by the pattern repeat:
Wall Height / Pattern Repeat
Round UP to the nearest whole number.
Then multiply by the pattern repeat:
Adjusted Drop Height =
(Wall Height x Pattern Repeat) ×Pattern Repeat
This gives the actual wallpaper length needed per drop after allowing for pattern matching.
Then — Calculate total wallpaper length required
Multiply:
-
adjusted drop height
× -
number of drops
Total Length Required = Drops Required × Adjusted Drop Height
Finally — Calculate rolls required
Divide by roll length (10m):
Rolls Required = (Total Length Required / 10)