How Much Wallpaper Do I Need? A Practical Guide & Calculator

9 July 2026

Falling in love with a bold conversational print or a rich, statement wallpaper is the exciting part. Figuring out exactly how many rolls to order? Less so.

Ordering too little means mid-project delays. Ordering too much leaves you with leftover rolls. At Harlequin, we want your DIY project to run flawlessly.

Here is our quick guide to calculating your wallpaper needs accurately, from simple feature walls to tricky, awkward spaces.

Image of rolls of wallpaper in blue and green from henry holland collaboration with Harlequin

1. THE SIMPLE MEASUREMENT METHOD

Before jumping in, grab a steel tape measure (fabric ones can stretch) and note down your wall dimensions in metres or centimetres.

Step 1: Measure the total width

Measure the horizontal width of each wall you intend to paper. Add these widths together to get your total horizontal distance.

Step 2: Measure the maximum height

Measure vertically from the top of your skirting board to the ceiling or coving. Measure in a few different spots, as older houses rarely have perfectly straight walls; always use the highest measurement.

Step 3: Do not subtract doors and windows

It is tempting to cut out large windows or double doors from your calculations, but keeping them included gives you a safety buffer for trimming and alignment.

Image of bedroom covered in green wallpaper from henry holland collaboration with harlequin

2. NAVIGATING PATTERN REPEATS & TRICKY CORNERS

Standard wallpaper calculators work beautifully for plain walls, but designer wallpapers with large, expressive motifs require a bit more strategy.

The Pattern Repeat Factor: When your wallpaper has a pattern, each drop needs to be lined up perfectly with the last. This means a portion of the paper at the top of each strip will be trimmed away. Check the product specifications on our website for the Repeat Height (e.g., 52cm) and look out for whether it is a Straight Match or a Drop Match, as this impacts how much excess you will need.

Sloped Ceilings & Alcoves: If you are wallpapering an attic space or a room with a chimney breast, treat each section as a full rectangle based on its tallest and widest points.

Tricky Corners: Always allow an extra 5–10cm of width to wrap around internal or external corners. Walls are rarely perfectly plumb, and this ensures you don't run out of coverage mid-corner.

Image of flowers in vase in front of green patterned wallpaper

3. SKIP THE MATHS: USE OUR ONLINE WALLPAPER CALCULATOR

Instead of working out the surface area manually, let our digital tools do the heavy lifting for your home or design project.

Every wallpaper product page across the Harlequin website features our tailored Online Calculator. Simply find your favourite design, enter your wall width and height, and our system automatically factors in that specific width and pattern repeat to tell you exactly how many rolls to add to your basket.

The golden rule? Always add one extra roll to your final order. This covers unexpected mistakes and leaves you with a spare for any future repairs.