How much wallpaper do I need? Work out the right amount with this expert advice

'How much wallpaper do I need?' - it's a mind-boggling moment for many a DIYer. Let's face it, doing your own decorating can save money - and time. (Depending where you live the waiting list for a tradesperson can stretch into next year). However, wallpapering is not without its pitfalls. 

So if you've decided to roll up your sleeves and do it yourself, it pays to do the prep work properly. This includes calculating the rolls of wallpaper required, so you're not falling short or spending cash on too much surplus. 

Start with your favourite wallpaper ideas, then once you've decided what you want, you can work out what you'll need.

'Wallpaper can sometimes seem intimidating when it comes to measuring up but following some steps makes it much easier,' says James Greenwood, interiors expert at Graham & Brown.

How do I calculate how many rolls of wallpaper I need?

Take your time and begin by measuring your room and the coverage of the wallpaper roll in these stages. 

1. Work out the width of your walls

'To calculate the amount of wallpaper rolls you'll need, measure the width of each wall and add them together to get the overall width of the room,' says James at Graham & Brown. 

2. Measure the height of your walls

'Then measure the height of your walls (or as high as you wish to cover, eg up to a dado rail) from the skirting board and multiply that figure by the total width of the room (or just the wall if it's for a feature wall) to get the overall square meterage.'

'When measuring, use a good quality rigid measuring tape, and round up to the nearest whole number,' adds Alex Whitecroft, head of design at I Want Wallpaper. 

3. Calculate the coverage of the wallpaper roll

'All of our wallpapers are 52cm wide and 10 meters long so one roll will cover 5.2 square metres,' says James at Graham & Brown. 'By dividing the overall square meterage of the room by the roll coverage you can calculate the approximate amount of rolls you will need.' 

'However, many people will make the mistake of ending here and not accounting for the factors that may result in requiring more wallpaper, such as the repeat length.'

For example a room measuring 26 square metres, divided by 5.2m would equate to 5 rolls of wallpaper. However, this doesn't allow for pattern repeats or wastage, so you will need more rolls in order for the pattern to match up.

4. Include the pattern repeat

'If your chosen wallpaper has a large pattern repeat you will need extra rolls as more paper is used when matching the pattern on the walls. Find out the length of the 'repeat' and an online wallpaper calculator will let you input the measurements of the room, the size of the wallpaper roll and finally the length of the ‘drop’ repeat. 

'This is important as you will need more rolls of paper to allow for the pattern to meet in the correct place, as there’s more wastage with pattern repeats,' explains James.

'I always recommend adding at least 10% on top of any calculation to account for mistakes, recuts or replacements in future too,' says Alex Whitecroft, head of design at I Want Wallpaper. 'While saving on budget is important, when it comes to wallpaper it’s definitely better to have more than less.'

How to measure for wallpaper around windows and doors

Even if you know how to wallpaper, it's worth allowing extra wallpaper for mistakes. For ease when matching up patterns experts suggest including windows and doors in the wall measurements. 

'Remember to measure even if there are doorways, windows and inset cupboards as the wallpaper will need to be cut around these,' says Lorraine Aaron, Founder of Curious Egg. 'Considering them as part of the wall ensures the pattern continues correctly. 

'We always recommend including windows and doors within your measurements to ensure you have enough wallpaper to complete your room,' says Chelsea Clark at I Love Wallpaper. 

'If you under order and need more, you may find that the batch number you need is out of stock so any new rolls may have some colour variation and will not be an exact match. It’s always better to have a little bit extra.'

How to measure for wallpaper in an awkwardly shaped room

Measuring for wallpaper in an awkwardly shaped room is not that different to measuring a square room. Just be sure to measure each section to get the total width.  

'For ease to ensure a pattern match, measure as if it is a full wall,' says Chelsea Clark at I Love Wallpaper. 'For example, when wallpapering a chimney breast, ensure you include the chimney depth measurements, as well as the width, within the overall wall measurements to ensure you order enough paper.'  

If you are decorating around a mantlepiece, it's worth checking how to wallpaper a chimney breast, as this will give guidance about where to start the pattern. It's likely to be a feature in the room, so you'll need to decide whether to centre the seam or the pattern, depending on the design you've chosen. 

Where can I buy wallpaper?

Wallpaper can be expensive, with eye-catching designer styles costing upwards of £200 per roll. However if you're canny that doesn't have to be the case. The following retailers offer a fantastic selection of affordable styles from as little as £12 per roll. 

1. Iwantwallpaper

This online retailer offers all the latest wallpaper trends from faux marble and metallics to geometrics. As well as classic damask and floral prints, all at extremely affordable prices. 

iwantwallpaper.co.uk

2. Graham & Brown

A wallpaper stalwart this family owned company not only offers designer collaborations from the likes of 2LG and Julien MacDonald, alongside its gorgeous inhouse designs, it offers paint, curtains and blinds too.

Graham & Brown

3. Ilovewallpaper

From scrubbable and waterproof options to wow-factor wall murals, there's a fantastic array of styles and trends here, spanning maximalist to minimalist and much in between.

Ilovewallpaper.co.uk 

4. Wallpaper Direct

This powerhouse of paper, stocks a who's who of wallpaper brands, from premium names such as Andrew Martin, Designers Guild and Zoffany, through to High Street fashion collaborations from Accessorize and Ted Baker.

Wallpaper Direct

How much does one roll of wallpaper do?

This obviously depends on the size of the roll and the room. However, a standard sized wallpaper roll is usually 50cm or 52cm wide and 10m long, which equates to 5 or 5.2 square metres. This is roughly three to four vertical drops in an average height room. Note that not all manufacturers follow this sizing, so always check the size of the roll. 

For other non-standard sizes, to work about how much coverage one wallpaper roll will do, multiply the width by the length to get the square metre coverage. Be aware also that more expensive wallpapers are often sold by the metre. 

'Some papers are hung like murals in fixed size panels, side by side. Others have a drop repeat so you’ll need more rolls than you would if there was no drop repeat,' says Lorraine Aaron at Curious Egg. 

'Always calculate what you need and add an extra roll if in doubt. Rolls are made in batches, so if you use one from a different batch the colour may vary slightly. It's also important to note that some are ‘paste the wall’ rather than the paper so always check application instructions too.'

'It’s best to stick to the old adage - measure twice, cut once - to ensure you get the right coverage first time around,' says Alex Whitecroft, head of design at I Want Wallpaper.

'Although, it’s always handy to have a spare roll or two left over just in case. Errors can happen, either through a miscalculation or a miss-cut when it comes to matching patterns. Spare rolls mean you’re ready in case you need to replace a panel down the line.'

How much wallpaper do I need with a pattern repeat?

This is where calculating rolls can become trickier. With larger pattern repeats you'll need more paper in order to line up the pattern. Consider this if you're looking for living room or bedroom wallpaper ideas, if you're on a budget.

'The number of wallpaper rolls you need for a pattern repeat depends on the particular paper you have chosen,' says Alex at I Want Wallpaper. 'A pattern repeat is the distance between two matching design elements on a roll of wallpaper. This distance helps determine how many rolls you will need. 

'A wallpaper’s pattern repeat can usually be found on the roll itself, but you can also find it in the wallpaper sample book or on the manufacturer's website using the design's name or product number.'

'With pattern repeats, there's some extra measuring you need to take into account,' says Emma Deterding, Founder of Kelling Designs.

'The joyous thing about small pattern repeats is that you don’t waste as much paper. However with big pattern repeats, you can be in danger of wasting much more paper which can be costly if it's an expensive, designer paper. So bear this in mind when choosing the design.

'You'll need to add the length of a pattern repeat for each drop, bar the very first one. Then multiply the number of drops by the width of the pattern repeat. This number then gets added to your previous totals to work out the amount of paper needed in meters to cover all the walls,' explains Emma. 

'This then figure then gets divided by the length of the roll to work out exactly how many rolls you need. Remember to always round up so you don't end up short.'