Wallpaper Calculator
Calculate wallpaper rolls for any room or feature wall. Covers all roll sizes with random, straight and half-drop pattern repeat. Includes paste sachets and batch number reminder. 2026 UK pricing.
Standard UK roll: 10.05m long × 530mm wide. Check the label on your roll for exact dimensions.
0.9m wide each
1.2m wide each
Tip: only deduct large openings (patio doors, wide bays). Leave small windows as solid wall — you'll need full drops above and below anyway.
Wallpapering Guide
Pattern Matching & Hanging Tips
Understanding pattern repeat types
Random match (free match): No vertical pattern alignment needed. Each strip can start at any point. Minimal waste — only the 50–100mm trim at ceiling and floor. Best value for money and easiest to hang.
Straight match: The pattern repeats horizontally at regular intervals. Every drop must start at the same point in the pattern, so you may need to cut into the roll to find the right starting position. Waste per drop ≤ one full repeat.
Half-drop (offset match): The pattern shifts diagonally — alternate strips are offset by half the pattern repeat. This means cutting alternately from two different starting points in the roll, wasting up to half a repeat on every other strip. Plan carefully and cut from two separate rolls alternately to reduce waste.
Where to start in a room
Start from the most visible focal wall and work outwards in both directions. Draw a true vertical line with a plumb bob or spirit level — never use a door frame or window reveal as a guide since they are rarely truly vertical.
For feature walls: centre the first drop on the wall centre point so the pattern is symmetrical. For patterned papers with a large repeat, position the pattern at eye level on the most visible wall first, then work to the corners where the pattern cut-off will be less obvious.
Paste types and coverage
Standard ready-mixed paste sachets are labelled for 5 or 10 rolls at a stated concentration. Heavy or thick wallpapers (embossed, textured, non-woven) may need paste mixed slightly stronger, reducing coverage to 4–5 rolls per sachet.
Paste-the-wall (non-woven) papers: paste is applied to the wall, not the paper. Use a short-pile roller to apply evenly, then hang the dry paper into it. This is much faster than pasting the paper and eliminates the soaking step. Check the paper specification — not all non-woven papers support paste-the-wall application.
FAQ
Common Questions
For a 4×3m room at 2.4m ceiling height: perimeter (minus 1 door, 1 window) = ~11.9m. Drops = 11.9 ÷ 0.53 = ~23 drops. Drops per roll = floor(10.05 ÷ 2.5m) = 4. Rolls = ceil(23 ÷ 4) + 1 spare = 7 rolls total. With a 53cm pattern repeat, drops per roll drops to 3, giving 9 rolls total.
Only deduct wide openings like patio doors or large bay windows. For standard doors and windows, you still need full drops above and below them — the offcuts are rarely usable elsewhere. Our calculator subtracts the width from the perimeter, which gives a reasonable estimate, but many decorators prefer not to deduct standard-size windows at all to ensure sufficient material.
The pattern repeat is the vertical distance in centimetres before the design repeats again. It is printed on the roll label alongside pattern match symbols. A 53cm straight match means every 53cm the design repeats exactly. This figure is added to each drop length when calculating how many drops you can get from a roll.
Yes — always size (prime) walls first. Diluted paste or proprietary size seals absorbent plaster, preventing it from sucking paste out of the paper too quickly. This gives you time to position the paper correctly. Fresh plaster must cure for at least 6 months, or use a specialist new-plaster primer before papering over it.