Wallpaper Coverage Explained: Rolls, Pattern Repeat, and How Much You Need

Wallpaper is sold by the roll, but walls are measured in square metres, and the gap between the two is where most shortages happen. A roll’s coverage on the label assumes no pattern, no waste, and no awkward corners. Real walls have doors, windows, sockets, and a pattern that must line up at every join. This guide explains how to measure, how pattern repeat eats coverage, how to allow for waste without buying a second project, and how to order so that every roll comes from the same batch. Buy one roll too many and you have a spare for repairs. Buy one too few and the extra roll may not match.

Measuring the walls

Measure the width of each wall and the height from floor to ceiling — or to the top of the area being papered, if a dado rail or border divides it. Multiply width by height for each wall, add the walls together, and you have the gross wall area. Then subtract the areas of doors, windows, and any other openings that will not be papered. A standard door is about 2 square metres, a window varies, and measuring the actual opening is always better than guessing.

Do not subtract sockets, switches, and small fittings. They are papered over and cut out, and their area is negligible. Do subtract anything large that interrupts the wall — a fireplace opening, a fitted wardrobe that reaches the ceiling, a large built-in unit — because those areas genuinely need no paper, and counting them inflates the order.

Worked example: a room with four walls, each 4 metres wide and 2.4 metres high. The gross area is 4 × 4 × 2.4, which is 38.4 square metres. Subtract one door of 2 square metres and one window of 2.4 square metres, and the net area is 34 square metres. That net figure is the area to cover — before pattern repeat and waste, which are the subject of the next section.

Try the method on your own figures with the Wallpaper Calculator.

Rolls, coverage, and the pattern repeat

A standard roll in most markets is 10.05 metres long and 0.53 metres wide, giving a gross area of about 5.33 square metres. That figure is printed on the roll, and it is the area of paper in the roll, not the area of wall it will cover. The wall area it covers depends on how the roll is cut into drops — the vertical strips that run from ceiling to floor — and on how much of each drop is wasted matching the pattern.

Cutting works like this. Divide the roll length by the drop length — the wall height plus a trimming allowance of about 10 centimetres, 5 at the top and 5 at the bottom. A 2.4-metre wall needs drops of about 2.5 metres, and a 10.05-metre roll yields four drops of 2.5 metres, with a few centimetres left over. Each drop covers 0.53 metres of wall width, so one roll covers about 2.12 metres of wall width at that height, before pattern matching.

Pattern repeat changes the arithmetic. If the pattern repeats every 64 centimetres, each drop must start at the same point in the pattern, and the offcut between the end of one drop and the start of the next matching point is wasted. With a large repeat, a roll that yields four plain drops may yield only three matched drops, and the coverage falls by a quarter. The larger the repeat and the shorter the wall, the worse the waste: a tall wall uses most of each drop, while a short wall under a large repeat throws much of it away.

Waste, awkward walls, and the spare roll

Allow waste on top of the net area. A common allowance is 10% for plain or small-pattern papers on straightforward walls, and 15% to 20% for large repeats, feature walls with many cuts, or rooms with alcoves, chimney breasts, and sloping ceilings. The waste allowance covers trimming, matching, mistakes, and the short lengths that remain after cutting drops around openings.

Awkward features deserve their own thought. A chimney breast adds corners and short returns that consume paper out of proportion to their area. A sloping ceiling means drops of different lengths, and the longest drop sets the cutting length for the whole wall. An alcove needs paper on its sides and back, and the pattern must continue around the corner. In each case, measure the feature as its own small wall, and do not assume the main-wall calculation covers it.

Always round up, and then add one spare roll. The spare covers a future repair — a scuff, a stain, a child’s drawing — and it covers the case where the calculation was optimistic. A spare roll costs the price of one roll. A shortage costs a second order, a delivery wait, and the risk that the new batch does not match. Buy the spare.

Batch numbers, and ordering

Wallpaper is printed in batches, and the colour can vary slightly between batches — the same design, the same code, a visibly different shade at a join. The batch number is printed on the roll label. Order all the rolls for one room at once, from the same batch, and check the batch numbers when they arrive, before opening them. If two batches arrive, return the odd one before it is cut: an unopened roll can be exchanged, a cut one usually cannot.

Check the roll for its other particulars at the same time: the pattern repeat, the paste method, and the hanging instructions. Papers divide into paste-the-wall, paste-the-paper, and peel-and-stick, and the method changes the tools, the time, and whether the paper can be repositioned. A paper bought for one method cannot be hung by another without trouble.

Keep one unopened roll, or at least a full drop, after the job. Store it flat or upright in a dry place, away from sunlight, with the batch number recorded. When a repair is needed years later, that roll is the only paper guaranteed to match, and it will be worth far more than the shelf space it occupies.

Costing the job honestly

The cost of a papering job is the paper, the paste or adhesive, the tools, and the time — and the paper is usually the smallest part of the time cost if a professional is doing it. Price the paper by the roll, including the spare, and price the paste by the coverage stated on its packaging for the paper type. Primer or lining paper, where the wall needs it, is a separate cost that should be decided before ordering, not discovered halfway through.

Compare papers by covered wall area, not by roll price. A cheaper roll with a large repeat can cover less wall than a dearer roll with a small repeat, and the dearer roll can be the cheaper job. The calculator shows the covered area per roll for the repeat and wall height entered, which is the comparison that matters.

Finally, measure twice. The most expensive wallpaper mistake is not a wrong price but a wrong quantity, discovered with one wall left and no matching paper available. Measure every wall, subtract the openings, add the waste, round up, add the spare, and check the batch numbers. It takes twenty minutes, and it is the difference between a finished room and a stalled one.

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