How many rolls of wallpaper do I need?

How many rolls of wallpaper you need is always a necessary calculation for wallpapering a room, and you’ll find many versions of different ‘wallpaper calculators’ online. In my guide ‘Wallpapering a room’ I show one fairly mathematical technique, but unless the room or rooms are very complicated or unusual in design, I tend to go for a far simpler option that I’ve detailed below. To make any calculation, you need to know what size of pattern repeat your choice of wallpaper has, as well as the dimensions of the roll. So, firstly I’ve provided a little more information about pattern repeats and roll sizes, followed by my favourite technique for adding up the number of rolls I require.

Pattern repeats and wallpaper roll sizes

The pattern repeat size is basically the measurement that denotes the complete height of the motif or design used on your wallpaper, before it gets printed again, and repeats itself. This is best seen by looking along the edge of a wallpaper length, choosing half a flower for example, and measuring down to the next time that exact same shape of half flower appears. Luckily, most manufacturers will detail on their rolls the size of pattern repeat, so you simply take note of this and use it in your calculation. Many wallpapers will have no pattern repeat, for example, a basic striped pattern. Large motifs will always result in a large repeat, but be aware that even a dainty little pattern may still have a large pattern repeat, so always pay close attention to the manufacturer’s measurements.

Wallpaper roll sizes do vary, but most standard wallpapers in the UK are slightly over 10m (just over 32ft) in length by 52cm (20.5in) in width. For my technique below, I’ll be using these standard measurements as well as an average ceiling to skirting board height of 2.3m (7.5ft), so you’ll need to adjust your figures if using a different size of wallpaper roll, or rooms with higher or lower ceilings.

Measuring for the number of rolls of wallpaper

  • Wallpaper calculator

    Simply start in one corner, and keep moving round.

    Open a tape measure up to 52cm (20.5in) (i.e. roll width).

  • Start in one corner of the room, measure to 52cm (20.5in) and then simply move along to position the start of the tape at the 52cm mark, and keep repeating this as you go around the room. Therefore you effectively count the number of lengths or drops of wallpaper you will require.
  • Go straight over the top of the door and the window(s) and keep going around the room until you get to your starting point. The diagram to the right shows this principle, although I’ve only gone up to length number 7 in order to keep things clear. Also note how length 6 actually bends around the corner, so every time you get to a corner, simply bend the tape measure around it.
  • With the number of lengths of wallpaper required, now you work out how many lengths you will get out of a roll, and this is where the pattern repeat also needs considering.
  • Simply add the repeat onto your wall height requirement. So if the repeat is 10cm, you add it to your 2m 30cm height making 2m 40cm. Divide your 10m roll by this 2m 40cm which is just over 4, so you basically get 4 lengths per roll. Divide the number of lengths by lengths per roll (4 in this case), and that gives you your exact roll requirement. However………..
  • Always round your number of rolls required figure ‘up’ rather than ‘down’.
  • Because you’ve measured over doors, windows etc. you do have a bit extra already in your calculation. However, for an average room, it’s best to get 10% more than required as an extra trimming allowance, which effectively means you buy an extra roll.

If you have a complex room, or area, with differing wall heights, such as a stairwell, then you are generally best using the technique I link to in my introduction. Otherwise, if it’s a simple room, the technique above for calculating how many rolls of wallpaper you need always works for me.

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