How Much Wallpaper Do You Need?

Wallpaper is unforgiving to under-order: a second batch may not match the first, so running short can ruin a wall. Working out how much wallpaper you need in advance avoids that, and the calculation is quick once you know that wallpaper is sold in rolls of a standard size. The method is to measure your total wall area, then divide by how much one roll usefully covers, adding a margin for pattern matching. This guide walks through both the area method and the drop-counting method with a worked example, and explains why pattern repeats mean buying a little extra. To measure walls, our area calculator helps, and it pairs naturally with estimating paint.

Standard roll size

A standard wallpaper roll is roughly 10 metres long and about 0.53 metres wide, which is a little over 5 square metres of paper. In practice, you only get around 5 square metres of usable coverage per roll once you allow for trimming and matching. Roll sizes vary by country and brand, so always check the label, but this is a reliable planning figure.

The area method

1. Measure the room perimeter: 2 times (length plus width).
2. Multiply by the wall height to get the total wall area.
3. Divide by about 5 square metres per roll, then round up.
4. Add an extra roll for pattern matching and mistakes.

For small windows and doors, many decorators do not subtract the area, because the offcuts are lost to pattern matching anyway. Subtract only large openings.

A worked example

Take a room 4 metres by 5 metres with walls 2.4 metres high.

1. Perimeter: 2 x (4 + 5) = 18 metres.
2. Wall area: 18 x 2.4 = 43.2 square metres.
3. Rolls: 43.2 / 5 = 8.64, so round up to 9 rolls.

In plain English: this room needs about 9 rolls, which already includes a sensible margin. If the wallpaper has a large pattern repeat, you might add one more to be safe.

Measure the walls

Our area calculator makes measuring wall area easy, and the same walls you paper are the ones you might paint, so see our guide on how much paint you need too.

The drop-counting method

Professionals often count drops instead. A drop is a single vertical length of wallpaper from ceiling to skirting. First work out how many drops one roll gives: divide the roll length by the wall height, allowing for trimming. A 10-metre roll gives about 4 drops on a 2.4-metre wall.

Then work out how many drops you need in total: divide the room perimeter by the roll width. For an 18-metre perimeter and 0.53-metre-wide paper, that is about 34 drops. Divide 34 by 4 drops per roll to get about 9 rolls, matching the area method.

Why pattern repeat matters

Patterned wallpaper must line up across each drop, so you trim off some paper at the top of each length to match the design. The larger the pattern repeat, the more you waste per drop, and the fewer usable drops you get from a roll. For papers with a big repeat, add an extra roll or two, and always check the pattern repeat printed on the roll before ordering.

Frequently asked questions

How much wallpaper do I need?

Calculate the total wall area by multiplying the room perimeter by the wall height, then divide by about 5 square metres, the usable coverage of a standard roll, and round up. Add an extra roll for pattern matching. A 4 by 5 metre room with 2.4 metre walls has about 43 square metres of wall, needing roughly 9 rolls.

How many square metres does a roll of wallpaper cover?

A standard roll is about 10 metres long and 0.53 metres wide, giving just over 5 square metres of paper. In practice you get around 5 square metres of usable coverage per roll after trimming and pattern matching. Roll sizes vary by brand and country, so always check the label for the exact dimensions.

Do I subtract doors and windows when calculating wallpaper?

For small windows and doors, many decorators do not subtract them, because the paper trimmed around openings is often lost to pattern matching anyway, and it provides a safety margin. Only subtract large openings, such as big patio doors or a wide window, where the saved area is significant enough to reduce your roll count.

How does pattern repeat affect how much wallpaper I need?

A pattern repeat means each drop must line up with the next, so you trim off some paper to match the design, wasting part of every length. The larger the repeat, the more you waste and the fewer usable drops per roll. For large patterns, add one or two extra rolls, and check the repeat on the label first.

What is the drop method for wallpaper?

A drop is one vertical length of wallpaper from ceiling to floor. To use the drop method, divide the roll length by the wall height to find drops per roll, then divide the room perimeter by the roll width to find total drops needed. Dividing total drops by drops per roll gives the number of rolls.

The bottom line

To work out how much wallpaper you need, find the total wall area (perimeter times height), divide by about 5 square metres per roll, round up, and add one for pattern matching, so a 4 by 5 metre room needs roughly 9 rolls. The drop method gives the same answer by counting vertical lengths. Always check the roll size and pattern repeat on the label. Measure your walls with our area calculator.

Further reading

For authoritative background on this topic, see Wallpaper on Wikipedia.