There are so many different ways to calculate how much wallpaper you need - and what makes it trickier is everyone hangs slightly differently. Some wallpaper hangers can actually you save you product by using every second roll (more about that later) so it is worth getting your installer to calculate. We always calculate from the largest pattern repeat number - it is safer and better to have more than needed than not enough.
We had someone come back to us a year after purchase to say she didn't have enough (as she forgot to calculate using the repeat) and the design had been discontinued.
This symbol indicates 'Offset'. As you can see one arrow is much higher, and the second arrow much lower indicating where the pattern repeats
Technically an offset match is simply a design which 'every second strip must be offset or dropped by the distance of its drop match'. Basically, the edge of the wallpaper only matches the edge of the second strip when it is dropped by a specific distance.
Lets try to make it more simple - The right hand edge of the first strip only matches with the left hand strip of the next strip, when the second wallpaper is dropped by a specified distance. For example a label will state a 64/32cm offset match. This means the design repeats every 64cm and the point at which they match from left to right is every 32cm.
When calculating wallpaper volumes we always count from the largest number just to make doubly sure we have enough.