  ## Wallpaper pattern match explained

So you’ve picked out the perfect wallpaper and you’re ready to put in your order… but how many rolls do you need to buy? In most cases, because the pattern must line up and not all of the wallpaper will be usable, you can’t just calculate the squared area of the room and buy exactly that much wallpaper. Each different type of wallpaper match requires a different method to calculate the amount you’ll need. Grab a calculator and follow along with our simple explanations and formulas to find out exactly how much you’ll need – no more inaccurate online roll calculator estimations! Except ours... compare your results with our super accurate roll calculator!

### Pattern Match Symbols

First, you need to find out what kind of 'match' that your wallpaper has. Symbols indicating this information can be found directly on the roll or in the sample book on the back of the page. Additionally, after reading this guide, you could even measure the pattern repeat for yourself.

This information is important because it will effect how the wallpaper is hung and how much of it you'll need.  This paintable vertically striped wallpaper is free match, making it super simple to hang.

### Free Match Wallpaper Notice that the design elements don’t cross the edges of the wallpaper sheets – nothing to match!

Free match wallpaper also goes by the names ‘Open Match’, ‘No Match’, ‘No Repeat’ and ‘Random Match’. This type of wallpaper either doesn’t have a repeating pattern or doesn’t have any design elements that need to be matched at the seams. An example of this might be some sort of random texture or vertical stripes. This is the easiest type of wallpaper to hang and is great for beginners. As well, not much of it will be wasted.

Calculating how many rolls you need of a free match wallpaper:

Step #1: How many strips are in one roll?

This is the first question you need to ask yourself. Of course, this number will be effected by your wall height. Divide the length of the wallpaper roll by the height of your wall.

For Example: 10.05m (roll Length) / 2.50m (wall height) = 4.02 (strips in one roll)

The number of strips in a roll must be a whole number so you will always round this number down to the closest whole number. In this case the 4.02 strips will become 4 strips.

Caution! Notice that in our example each roll will only include 5cm waste (=0.02 x 2.50; that is only about 1 cm per strip). This leaves very little room for error and means you need to determine how much risk you are willing to take. If you have an imperfect wall or are a wallpapering novice, we advise buying an extra roll or two, depending on the size of your wall.

Step #2: What width will one roll actually cover?

Multiply the width of the strips by the number of strips in one roll to get the area you will actually be able to cover on the wall with one roll.

For example: 0.53m (roll width) x 4 (strips in one roll) = 2.12m (width covered)

Step #3: How wide is the wall?

Simply divide the entire width of the wall by the width that one roll is able to cover and you will be very close to the answer of how many rolls you will need.

For example: 3.12m (wall width) / 2.12 (width covered by one roll) = 1.47 (rolls needed)

Obviously, the number of rolls needed must be round up to the next whole number. The resulting 1.47 means that this person would buy 2 rolls of wallpaper.

That wasn't so hard, was it?

Let’s look at one more example with some different numbers and the formula:

Known Variables

Roll Length (RL) = 10.05m
Roll Width (RW) = 0.70m
Wall Height (WH) = 3.10m
Wall Width (WW) = 5.30m

Unknown Variables

Strips in 1 Roll (SR) = ?
Width Covered by 1 Roll (WC) = ?
Rolls Needed (RN) = ?

Step #1

SR = RL/WH

SR = 10.05/3.10
SR = 3.24
SR = 3 (round down)

Step #2

WC = WR x SR

WC = 0.70 x 3
WC = 2.10

Step #3

RN = WW/WC

RN = 5.30/2.1
RN = 2.52
RN = 3 (round up)

This person would need 3 rolls of wallpaper for their space! The regular patterning of this chic geometric wallpaper means it's a straight match. Every strip will be the exact same!

### Straight Match Wallpaper Each strip is exactly the same!

Straight match wallpaper has design elements that cross the edges of the wallpaper sheets and need to be matched up. When hanging this type of wallpaper, it is best to lay it out on the floor beforehand. You will notice that each strip of wallpaper will be cut to look exactly the same. These wallpapers usually have simple repeating patterns. Of course, straight match wallpapers will yield more waste than free match wallpaper because the paper will need to be shifted to match up the pattern and not all paper will be useable. But don’t fret about waste, there are plenty of creative ways to use leftover wallpaper!

Calculating how many rolls you need of a straight match wallpaper:

Straight match wallpaper has design elements that need to be lined up, so the process for calculating the amount of rolls need has one extra initial step added on to what you would do to calculate for free match wallpaper.

New Step #1: How many times can the pattern repeat itself given the height of the wall?

Enter stage left, the concept of pattern repeat. This is a number you will find on the roll that is sometimes shown as a number over zero and it is the distance between identical design elements that need to be lined up. You can even calculate this number by measuring the distance between identical design elements along one edge of the paper. What we will need to do is think about how many multiples of this number will fit on at least the height of the wall.

For example, if the wall height is 2.50m and the pattern repeat is 40 (0.40m). The identical design element will reoccur every 0.40m. You can think of 0m as the ground and the red arrow at 2.50m as the top of the wall:

0m … 0.40m … 0.80m … 1.20m … 1.60m … 2.00m … 2.40m .. .. 2.80m

Essentially, 2.80m will become the new ‘calculated height’ because 2.40m would be stopping short of the top of the wall. Now the same process as calculating for free match wallpaper is followed, except we pretend that that wall height is 2.80m.

Now follow the same process as calculating for free match using this new ‘calculated height’ instead of the actual wall height. Let's see what the formula looks like and try it with some new numbers:

Known Variables

Roll Length (RL) = 10.05m
Roll Width (RW) = 0.70m
Wall Height (WH) = 3.10m
Wall Width (WW) = 5.30m
Pattern Repeat (PR) = 64/0

Unknown Variables

Calculated Height (CH) = ?
Strips in 1 Roll (SR) = ?
Width Covered by 1 Roll (WC) = ?
Rolls Needed (RN) = ?

Step #1

0m … 0.64m … 1.28m … 1.92m … 2.56m .. .. 3.20m

CH = 3.20m

Step #2

SR = RL/CH

SR = 10.05/3.20
SR = 3.14
SR = 3 (round down)

Step #3

WC = WR x SR

WC = 0.70 x 3
WC = 2.10

Step #4

RN = WW/WC

RN = 5.30/2.1
RN = 2.52
RN = 3 (round up)

This person would need 3 rolls of wallpaper for their space. This grey floral wallpaper is an offset match wallpaper. You can see that the big flowers only repeat in the same position every other strip, giving it a less repetitive feel!

### Offset Match Wallpaper Offset match, or drop match, patterns don't repeat every strip!

‘Offset match’ or ‘drop match’ wallpapers have design elements that cross the edges of the wallpaper strips and need to be lined up. However, across the wall, these design elements might be bigger or made to look less regularly patterned. When you put the puzzle together on the floor before hanging it, you will notice that each strip does not look the same and you will need to cut off large pieces in order to align the design elements. 'Half drop' repeats will be identical every other strip whereas 'multiple drop' repeat wallpapers won't repeat for three strips or more! Offset match wallpaper is harder to hang and produces the most waste – but it sure does look amazing!

Calculating how many rolls you need of a free match wallpaper:

Here we will calculate for a half drop match wallpaper, meaning that every other strip will be identical. Half drop offsets are far more common than multiple drop. We can begin by just taking the first strip as the exact height of the wall.

Step #1: First strip is the same length as wall height

For example: The wall height is 2.50m so the first strip will also be 2.50m

Step #2: How many times can the pattern repeat given the wall height after being ‘half dropped'?

The following strips will all be dropped by a half of the repeat from the previous strip. The repeat indicator for a half drop wallpaper will be a number over its half. Like with the straight match wallpaper, we need to think about how many multiples of the pattern repeat can fit on the height of the wall. But instead of starting from 0, we start from half of whatever the repeat is.

For example, the wall height is 2.50m and the pattern repeat is 40/20. This means that the whole pattern is repeated every 0.40m and that it will be dropped by 0.20m from the previous strip. Right now, we are only interested in the dropped pattern repeat which begins a 0.20m

0.20m … 0.60m … 1.00m … 1.40m … 1.80m … 2.20m.. .. 2.60m

We are looking for the next highest length that is at least the height of the wall (2.50m). With a 40/20 repeat and a 2.50m wall height, the new ‘calculated height’ is 2.60m. Each strip after the first will be this long and the difference between this number and the actual wall height is waste. So if the calculated height is 2.60m but the wall is actually 2.50m, then 10cm will be waste from each strip. This is a good amount that gives some room for error but also doesn’t waste too much.

Step #3: How many strips come from one roll?

When calculating how many strips will come from one roll, we can begin by separating out the first strip by subtracting the wall height (length of the first strip) from the length of the entire roll.

For example, the first strip/wall height is 2.50m and the length of the roll is 10.05m.

10.05m (length of roll) – 2.50m (length of first strip) = 7.55m (remaining wallpaper)

Then we can divide the remaining wallpaper by the ‘calculated height’ to find out how many strips will come from the rest of the wallpaper.

For example: 7.55m (remaining) / 2.60m (calculated height) = 2.90 (strips from remainder)

This number will unfortunately need to be rounded down and the rest will be waste 2.90 strips will become only 2 strips. Waste doesn’t need to be wasted though; find other creative ways to use wallpaper leftovers.

Finally, add together the first strip with how many strips come from the remainder and we have how many strips will come from one roll!

For example: 1 (first strip) + 2 (strips from remainder) = 3 (strips from 1 roll)

Step #4: What width will one roll actually cover?

Continue by finding out how much width the strips from one roll will cover by multiplying the strips from one roll by the width of each strip.

For example: 3 (strips from 1 roll) x 0.53m (roll width) = 1.59m (width covered)

Step #5: How many rolls are needed?

Now divide the width of the wall by the width that one roll will cover to find how many rolls you will need for the entire wall.

For example: The wall is 3.12m and the width covered by one roll is 1.59m

3.12m (wall width) / 1.59m (width covered by one roll) = 1.96 (rolls needed to cover entire wall)

Obviously, the rolls needed to cover the entire wall value will needed to be rounded up to the next highest whole number. In this case, 1.96 rolls will become 2 rolls and because there was so much waste off of each strip. As well, it will not be necessary to buy extra rolls in this case.

Let’s look at one more example with some different numbers and the formula:

Known Variables

Roll Length (RL) = 10.05m
Roll Width (RW) = 0.70m
Wall Height (WH) = 3.10m
Wall Width (WW) = 5.30m
Pattern Repeat (PR) = 64/32

Unknown Variables

First Strip Length (FS) = WH
Calculated Height (CH) = ?
Remainder (R) = ?
Strips from Remainder (SRM) = ?
Width Covered by 1 Roll (WC) = ?
Strips in 1 Roll (SR) = ?
Rolls Needed (RN) = ?

Step #1

0.32m … 0.96m … 1.60m … 2.24m.. .. 3.52m

CH = 3.52m

Step #2

R = RL - FS

R = 10.05 - 3.10
SR = 3.14
R = 6.95

Step #3

SRM = R/CH

SRM = 6.95/3.52
SRM = 1.97
SRM = 1 (round down)

Step #4

SR = 1 + SRM

SR = 1 + 1
SR = 2

Step #5

WC = SR x RW

WC = 2 x 0.70
WC = 1.40

Step #6

RN = WW/WC

RN = 5.30/1.40
RN = 3.78
RN = 4 (round up) Offset match wallpapers like this leafy polka dot wallpaper by Schöner Wohnen look fun and spontaneous.

Give yourself room for error! Think about what type of person you are (careful and exact or the opposite of this) and factor this into how much wallpaper you buy. If your calculations tell you that you’ll have only exactly enough, consider buying another roll or two – especially with offset match wallpaper.

Besides mistakes that you might make, be aware that manufacturers allow for a roll to be 2-3% off from the amount labeled. With some bad luck you might be short even up to 30cm!

If it happens that you didn’t buy enough wallpaper and you need to order more, it is important that you find wallpaper from the same batch or dye lot. Wallpaper is one of those things that needs to match perfectly and it can be glaringly obvious when the extras you bought are not the same color! This batch number will be on the roll, so don’t throw it out or lose it until you know you won’t need it.

### To Summarize

• Different wallpaper matches are hung differently so amounts needed are also calculated differently.
• Free matching wallpaper is the easiest and produces the least waste./li>
• Straight matching wallpaper has only one extra step than free matching wallpaper./li>
• There are two types of offset match wallpaper – half drop or multiple drop
• Offset match wallpaper is the most difficult to hang and produces a lot of waste.
• Buy extra wallpaper to ensure you have enough of the same batch/ dye lot./li>
• Follow our clearly explained calculation step and don’t be intimidated by the math! 