# Wallpaper Calculator — Rolls, Pattern Repeat & Paste > Free wallpaper calculator: how many rolls to buy, counting drops, pattern repeat and straight vs. drop match waste, door and window deductions, paste and tools — all in your browser. Count the drops, handle the pattern repeat, and get the exact rolls to buy — with paste and a tool checklist to match. - **HTML page:** https://siteometry.com/en/tools/wallpaper - **Category:** [Decorating & Interiors](https://siteometry.com/en/tools/category/decorating-interiors) - **Figures live on the page:** tables, diagrams and worked figures the text refers to ("the table below") are drawn by the page and are not reproduced here. Each section below links to its anchor on the page. - **Runs in the browser:** Siteometry calculators need no account and send no input anywhere — every number below is computed on the visitor's own device. ## Five steps to your roll count 1. **Choose units and currency** — Pick metric (metres and centimetres) or imperial (feet and inches). Set a currency if you want a cost. 2. **Enter the room** — Set the ceiling height and add each wall's width. The tool shows the drops per wall as you type. 3. **Add doors and windows** — Set how many doors and windows there are and their sizes. They reduce the drops you need. 4. **Set the roll and pattern** — Choose the roll width and length, enter the pattern repeat (0 for plain), and pick straight or drop match. 5. **Set paper, waste and spares** — Choose the paper type for a paste recommendation, slide the waste buffer, and note any rolls you already have. 6. **Read the results** — Read the rolls to buy, paste packets and cost. Download a PDF buying list or export a CSV to bring to the shop. _On the page: https://siteometry.com/en/tools/wallpaper#howto_ ## Wallpaper roll & pattern calculator This calculator turns a room's walls into the one number a wallpaper shopper actually needs — how many rolls to buy — while handling the two things cheap calculators get wrong: the pattern repeat and the difference between a straight and a drop match. It works the way professional decorators do: in drops. A drop is a single floor-to-ceiling strip of paper. The tool counts the drops each wall needs, works out how many drops you get from one roll, then converts that into whole rolls, with a waste buffer and a spare you can adjust. _On the page: https://siteometry.com/en/tools/wallpaper#wallpaper-guide-intro_ ## How many rolls of wallpaper do I need? Start with the wall, not the roll. Add each wall's width and your ceiling height, and the calculator finds the drops per wall by dividing the wall width by the roll width and rounding up — a part-width strip is still a whole drop off the roll. A standard 53 cm × 10 m roll gives about four full drops on a 2.4 m ceiling once you allow for trimming, so it covers roughly four drops' worth of wall. Doors and windows shave drops off the total; the pattern repeat adds length to every drop. The calculator keeps all of this straight and gives you a roll count you can take to the shop. _On the page: https://siteometry.com/en/tools/wallpaper#how-many-rolls_ ## How the calculator works Enter the room, choose your roll and pattern, then read the rolls to buy from the results panel. Every figure updates as you type, and nothing leaves your browser. _On the page: https://siteometry.com/en/tools/wallpaper#how-calculator-works_ ## Pattern repeat and match type The pattern repeat is the vertical distance before the design starts again — it is printed on the roll label. For patterned paper, every drop has to be cut to a whole number of repeats so the design lines up across seams, which makes each drop longer than the bare wall height. How the pattern lines up across the seam matters even more. A straight (free) match repeats at the same height on the next drop. A drop (offset) match staggers every second drop by half a repeat, so the offcut from one drop can't start the next — costing about half a repeat of extra waste on every drop. It is the single biggest reason a job comes up short. _On the page: https://siteometry.com/en/tools/wallpaper#pattern-match_ ## Paste, tools and the formulas Heavier papers need stronger paste. The calculator reads your paper type and recommends a paste family and a number of standard packets — a safer figure than litres, because brand concentrations differ. Here is the maths behind the roll count. _On the page: https://siteometry.com/en/tools/wallpaper#paste-and-tools_ ## Worked examples Two runs through the same 4 m × 5 m room — once plain, once with an offset pattern — show how much the match type moves the roll count. _On the page: https://siteometry.com/en/tools/wallpaper#examples_ ## Common mistakes Buying short. The number-one cause is ignoring the pattern repeat, especially on a drop match. The waste buffer and the spare roll exist for exactly this. Mixing batches. Rolls from different print runs (batches) can differ slightly in colour. Buy all your rolls — including the spare — from one batch, and check the batch number on every label. Forgetting the offcuts don't always fit. Above a door or below a window you need short pieces, but on a patterned paper those offcuts rarely match, so the calculator only deducts openings conservatively. _On the page: https://siteometry.com/en/tools/wallpaper#mistakes_ ## Frequently asked questions Short answers to the questions people most often ask about estimating wallpaper, pattern repeats and paste with this calculator. ### How many rolls of wallpaper do I need? Add each wall's width and the ceiling height, choose your roll size and pattern, and the calculator counts the drops, works out the drops per roll, and gives you the whole rolls to buy — including a waste buffer you can adjust. ### What is a drop? A drop is one floor-to-ceiling strip of wallpaper. Decorators count drops rather than area because a roll is divided into whole drops, and that is what makes the roll count accurate. ### What is the difference between a straight match and a drop match? A straight (free) match repeats at the same height on each drop. A drop (offset) match staggers every second drop by half a repeat, so it wastes about half a repeat more per drop — often a roll or two more across a room. ### Does the pattern repeat really change how much I buy? Yes. Each patterned drop is cut to a whole number of repeats so the design lines up, which makes every drop longer than the bare wall height. A bigger repeat means fewer drops per roll and more rolls. ### What if my paper is plain? Enter a pattern repeat of 0. The calculator uses the fast path: every drop is just the wall height plus trim, with no pattern waste, so you typically need fewer rolls. ### Does it deduct doors and windows? Yes, conservatively. Openings reduce the drops in proportion to how much of the wall they cover, but because patterned offcuts above and below an opening rarely match, the deduction stays cautious so you don't end up short. ### Which paste should I use? Light and standard papers hang with all-purpose paste; heavy and vinyl papers need heavy-duty paste; embossed and textured papers suit a ready-mixed paste. The calculator recommends a type and a number of packets from your paper choice. ### I already have some rolls — can I account for them? Yes. Enter the rolls you already have and they are subtracted from the rolls to buy, so you don't over-order when finishing a job or redoing one wall. ### Can I use feet and inches? Yes. Switch between metric and imperial at the top. Room sizes use metres or feet; roll width, pattern repeat and trim use centimetres or inches. ### Does it handle US double rolls? The calculator works in single rolls. US wallpaper is often priced as a double-roll bolt but hung as two single rolls — enter the single-roll width and length from the label, and read the count as single rolls. ### Is the calculator private? Completely. Everything runs in your browser — no account, no upload, and nothing you type leaves your device. _On the page: https://siteometry.com/en/tools/wallpaper#faq_ ## Related calculators - [Tile & Flooring Calculator](https://siteometry.com/en/tools/tile) - [Flooring Calculator — Laminate, Vinyl Plank & Hardwood](https://siteometry.com/en/tools/flooring-calculator) - [Paint Coverage & Cost Calculator](https://siteometry.com/en/tools/paint) - [Countertop Calculator — Slabs, Area & Cost](https://siteometry.com/en/tools/countertop-calculator)