How Much Wallpaper Do I Need? How to Calculate Metres and Rolls, With Pattern Repeat, Doors and Windows

The short answer: count drops × drop length, not area

Wallpaper is hung in vertical lengths called drops, cut from ceiling to floor and placed side by side. So the amount you need is the number of drops multiplied by the length of each drop. For each wall, divide the wall width by the width one drop covers and round up; each drop is the ceiling height plus a trimming allowance of about 10 cm. As a starting point, here is what rectangular rooms need with a 2.4 m ceiling, without subtracting doors or windows and without spares.

Treat the table as a starting point only. The same floor area can need several metres more or less depending on the exact wall widths, a 2.4 m or 2.5 m ceiling, the pattern, and where the doors and windows are. The rest of this guide shows where the amount goes up or down. To work out your own room, enter its width, depth and ceiling height into the Wallpaper Calculator; it counts drops and lengths including doors, windows and pattern.

The formula, and why dividing the area comes up short

The calculation has three steps, and each one involves rounding up. Round down or leave a fraction anywhere and you will run short partway through the job.

1. 1

   1. Work out how wide each drop covers

   Wide vinyl wallpaper is usually overlapped 2–3 cm and the two layers are cut together with a knife (double-cutting). With 92 cm paper and a 2 cm overlap, each drop advances 90 cm. European non-woven wallpaper is butt-jointed, so the full 52 cm counts.

2. 2

   2. Round up the number of drops for each wall

   Divide each wall width by the width from step 1 and round up wall by wall. A 264 cm wall needs 264 ÷ 90 = 2.93 → 3 drops; a 352 cm wall needs 352 ÷ 90 = 3.91 → 4 drops. Paper is cut at each corner rather than wrapped around it, so rounding each wall separately is more accurate than dividing the whole perimeter.

3. 3

   3. Set the drop length and multiply

   Add 5 cm at the ceiling and 5 cm at the floor for trimming (10 cm in total) to a 240 cm ceiling height: each drop is 250 cm. The 2.64 × 3.52 m room needs 3 + 4 + 3 + 4 = 14 drops, and 14 × 2.5 m = 35 m. If the paper is sold by the metre, order 35 m.

The classic mistake is to divide the wall area by the paper width. The walls of this room total 2 × (2.64 + 3.52) × 2.4 = 29.57 m²; divided by 0.92 m that gives 32.1 m — about 3 m less than the 35 m counted by drops, which is more than a whole drop short. The area method leaves out the 10 cm trimmed from every drop and the width wasted at the end of each wall.

How to measure: every wall width, and the highest ceiling point

The calculation is only as good as your measurements. Plans are often dimensioned to the centre of the walls, which can differ from the inside width by several centimetres. Before you order, measure with a tape in this order.

• Measure each wall separately, close to the floor, from inside corner to inside corner (ignore skirting boards and coving)
• Measure the ceiling height in several places and use the highest figure; older homes can vary by 1–2 cm
• For doors and closets, measure the outside of the frame; for windows, measure the frame width and height and the height from the floor to the bottom of the frame
• Do not subtract switches, sockets or air-conditioner units — cut those holes out after hanging
• Write down columns that stick out and bulkheads where the ceiling drops as separate walls

You measure walls one at a time because the drops are rounded up wall by wall. A wall just over a multiple of 90 cm needs an extra drop: a 270 cm wall takes exactly 3 drops, but 271 cm takes 4. If a measurement lands near one of these boundaries, measure again.

How much do doors and windows save? Only drops that fit entirely inside them

You don't paper over doors and windows, so it's tempting to subtract them. But you can only subtract the drops that fit entirely within the width of the opening. The drops at the left and right edges of an opening still have to be cut from a full-height length.

Each replaced drop is swapped for short pieces instead of a full 250 cm length: above the window, 240 − 200 = 40 cm plus 10 cm of allowance makes 50 cm; below it, 90 cm plus 10 cm makes 100 cm. With one such door and one window in the 2.64 × 3.52 m room, only one of the 14 drops of 92 cm paper becomes two short pieces, so the walls need 13 × 2.5 m + 0.5 m + 1.0 m = 34.0 m. Subtracting every opening saves just 1 m compared with 35 m.

With 52 cm paper, four drops are replaced (one at the door, three at the window), so the full-height drops fall from 26 to 22 and the rolls from 7 to 6. A 10 m roll yields four 250 cm drops, so 22 drops take five and a half rolls, and the remaining 5 m of the sixth roll holds exactly the four 50 cm pieces above the door and window plus the three 100 cm pieces below the window. Add one spare drop, however, and you are back to 7 rolls. With roll-sold wallpaper you have to think in terms of how many pieces fit on each roll, not total length.

Pattern repeat and half drop: how much extra you need

With patterned wallpaper, the pattern on neighbouring drops must line up. So each drop is not simply ceiling height plus allowance: it is that length rounded up to a multiple of the pattern repeat. This is the “repeat 64 cm” figure printed on the label or in the sample book.

• Plain / no match: drop length = ceiling height + allowance (240 + 10 = 250 cm)
• Straight match (the pattern lines up straight across): round 250 cm up to a multiple of the repeat. With a 64 cm repeat, 64 × 4 = 256 cm
• Half drop (the pattern on the next drop is offset by half a repeat): add half a repeat on top. With a 64 cm repeat, 256 + 32 = 288 cm

Half-drop matching is common on designs that appear to run diagonally. Because each drop starts half a repeat lower than its neighbour, you have to shift where you cut, and more of each roll is wasted. For the 2.64 × 3.52 m room with one door, one window and one spare drop:

Straight 32 cm and 64 cm repeats give the same 256 cm drop because 256 cm is the first multiple of each above 250 cm. A bigger repeat doesn't always mean more waste — it depends on how the repeat fits the ceiling height. With 10 m rolls, though, as soon as a drop exceeds 250 cm by even a few centimetres, each roll yields three drops instead of four. That is why a few centimetres of pattern matching can add one or two rolls.

How many rolls? 10 cm of ceiling height can add two

For wallpaper sold in 10 m rolls, adding up the total length and dividing by 10 m gives the wrong answer. The offcut left at the end of a roll can't be joined to the next drop, so first work out how many drops one roll yields.

At a 240 cm ceiling, four 250 cm drops fit a roll with nothing wasted. At 250 cm, each drop is 260 cm, the fourth no longer fits, and the same room jumps from 7 rolls to 9. Use the 220 cm offcuts for the short pieces above doors and below windows. The calculator packs every cut length into the rolls longest first, so its roll count already includes reusing offcuts.

• If a drop is longer than a roll (stairwells, double-height rooms), it would need joining — choose a longer roll
• The same logic applies to long rolls: the walls of the example room (with door, window and one spare) at 36.5 m plus the ceiling at 10.86 m fit on one 50 m roll of 92 cm paper
• Rolls carry a batch (lot) number. Buy everything at once so every roll comes from the same batch

Papering the ceiling too

Ceiling paper is normally laid across the short side of the room and cut to the length of the long side. For a 2.64 × 3.52 m ceiling, 264 ÷ 90 = 2.93 → 3 drops, each 352 cm + 10 cm = 362 cm long: 3 × 3.62 m = 10.86 m, so order 11 m. The ceiling is calculated without pattern matching.

With 52 cm rolls, buying the walls (7 rolls) and the ceiling (3 rolls) separately makes 10 rolls, but if both use the same paper, 9 are enough: after two 362 cm ceiling drops, the rest of the roll still holds a 250 cm wall drop. If the ceiling is a different paper, count the two separately. Ceiling work is done looking up and is easy to get wrong, so allow an extra spare drop.

How much for a single feature wall?

A popular first DIY project is a feature (accent) wall — one wall behind the bed or TV in a bold colour or pattern. For one wall, round up the wall width divided by the drop width, then multiply by the drop length.

With only a few drops, one spare is a large share of the total. Still, buying a single extra drop of the same paper after miscutting the last one is a hassle, so include one spare. A 352 cm wall in 52 cm paper fits into 2 rolls (8 drops) even with the spare.

How many spares? The last step before you order

Everything so far assumes you hang every drop perfectly. In practice the knife slips, pasted surfaces stick together, or a drop goes up with the pattern in the wrong place. Whatever the room size, 1–2 spare drops is the usual allowance.

• First project or a pattern to match: 2 spare drops
• Experienced, plain paper: 1 spare drop
• Ceiling as well: 1 extra spare for the ceiling
• Pre-pasted paper should be hung soon after delivery, and paper bought later may not match the paste on what you have, so order the spares up front

In the example room, one spare takes the 92 cm paper from 34.0 m (doors and windows subtracted) to 36.5 m, so you order 37 m — 2 m more than the 35 m in the first table, and a realistic figure for what you will actually buy. Roll up any leftovers and keep them for repairs, so holes and peeling can be fixed with matching paper.

Painting instead: how many cans?

If you paint rather than paper, work from area instead of drops. Litres needed = area × number of coats ÷ coverage per litre, plus 10–20% for paint left in the roller and tray. Use the coverage printed on the tin for accuracy.

Larger cans are often cheaper per litre, so compare the “least left over” and “fewest cans” options on price. Painting over wallpaper or going from a dark colour to a light one may need a separate primer (sealer) as well as the top coats.

Five things to check before you order

Once you have a figure, check these five points before ordering. Each one is a common reason for trouble after delivery even when the arithmetic was right.

• How it's sold: by the metre or by the roll. By the metre, round the total up to whole metres; by the roll, count drops per roll
• Width and joining: products vary in width, and some are butt-jointed rather than overlapped. Set the width each drop covers from the product page and fitting instructions
• Pattern repeat and match: even paper that looks plain may have a fine pattern. If a repeat is listed, check whether it is a straight or half-drop match
• Paste: pre-pasted paper is meant to be hung soon after delivery; unpasted paper needs paste and tools. Plan the delivery date back from the day you will hang it
• Order once: order the total including spares in one go so it comes from one batch. For several rooms, add up all the rooms first

Width is the easiest to overlook. If you calculate for 92 cm paper and then choose a different width, the drop count changes: the 2.64 × 3.52 m room needs 26 full-height drops of 52 cm paper instead of 14. Decide on the product first, then recalculate at its width.

Using the calculator step by step

1. 1

   Enter the room size

   For “Whole room (4 walls)”, enter the room width, depth and ceiling height. For a feature wall, switch to “One wall at a time” and enter only the walls you are papering. Tick “Paper the ceiling too” if needed.

2. 2

   Add doors and windows

   Enter each door's width and height, and each window's width, height and height from the floor. Only drops that fit entirely within an opening are replaced with short pieces above and below.

3. 3

   Choose the wallpaper and pattern

   Pick 92 cm paper (by the metre or 50 m roll) or European rolls (52 cm × 10 m, 53 cm × 10.05 m). For patterned paper, set the match (straight or half drop) and the repeat. For any other width or roll length, just change the numbers.

4. 4

   Set spares and check the result

   You get the metres or rolls needed, the number of drops and the length of each. Check the seams and drops per wall on the unrolled wall diagram, and plan your cutting from the cutting list.

5. 5

   Copy the result for ordering

   “Copy result” gives a summary of wall widths, drop length, drops and metres (or rolls) to paste into notes or a message. If you're painting, the “Paint cans” tab works out cans for the same room.

Common mistakes and how to avoid them

The formula is simple, but there are many places to round up, so mental arithmetic and area calculations tend to come out low. Enter your measurements, confirm the drops and lengths, and then order — you will keep both waste and shortfalls to a minimum.

FAQ

How much wallpaper do I need for a 2.64 × 3.52 m room?

With a 2.4 m ceiling, the walls need 14 drops — 35 m of 92 cm paper. Subtracting a door and a window gives about 34 m, and adding one spare makes 36.5 m (order 37 m). The ceiling needs about 11 m more. In 52 cm × 10 m rolls, the walls take 7 rolls.

How do you calculate how much wallpaper you need?

For each wall, divide the width by the width one drop covers and round up, then multiply by the drop length (ceiling height + about 10 cm). For 92 cm overlapped paper each drop covers 90 cm; for 52 cm butt-jointed paper it covers 52 cm. Dividing area by width ignores trimming and partial drops, so it comes out short.

How many rolls of wallpaper do I need?

With 52 cm × 10 m rolls, a 2.64 × 3.52 m room with a 2.4 m ceiling needs 26 drops, or 7 rolls, because each roll yields four 250 cm drops. At a 2.5 m ceiling each drop is 260 cm, only three fit per roll, and it becomes 9 rolls. Patterned paper can need more.

How much extra wallpaper does a pattern repeat need?

Each drop is rounded up to a multiple of the repeat, and a half drop adds another half repeat. At a 2.4 m ceiling with a 64 cm repeat, a straight match needs 256 cm drops and a half drop 288 cm. In the example room, 92 cm paper goes from 37 m (plain) to 38 m (straight) or 43 m (half drop); 52 cm rolls go from 7 to 8–9.

Can I subtract doors and windows from the wallpaper quantity?

Only the drops that fit entirely within the opening's width. An 80 cm door saves nothing with 92 cm paper hung at 90 cm per drop; a 165 cm window replaces one drop with short pieces above and below. The saving is about one drop, so on a first project it's safer not to subtract.

How much wallpaper do I need for one feature wall?

For a 352 cm wall with a 2.4 m ceiling: 4 drops (10 m) of 92 cm paper, or 12.5 m (order 13 m) with one spare. In 52 cm × 10 m rolls it's 7 drops — 2 rolls, still 2 with a spare. A 264 cm wall needs 3 drops of 92 cm paper, or 10 m with a spare.

How much wallpaper do I need for a ceiling?

Lay it across the short side and cut it to the long side. A 2.64 × 3.52 m ceiling needs 3 drops of 362 cm — 10.86 m, so order 11 m. A 3.52 × 3.52 m ceiling needs 4 drops, about 15 m. If walls and ceiling use the same rolls, counting them together lets offcuts be reused and can save a roll.

How much spare wallpaper should I buy?

One or two drops regardless of room size: two for a first project or a matched pattern, one if you're experienced and the paper is plain. A different production batch can be a slightly different shade, so order everything, spares included, at the same time.

How much paint do I need for the walls of a small bedroom?

For the 2.64 × 3.52 m example room, the walls minus a door and a window are 26.15 m². Two coats of paint that covers 8 m² per litre, plus 10% waste, is about 7.2 L — for example 3 L × 2 + 0.7 L × 2 (7.4 L) or 7 L + 0.7 L (7.7 L). Including the ceiling it's about 9.8 L: 7 L + 3 L.