Wallpaper Calculator

Enter your room dimensions, roll size, and pattern repeat to get an accurate roll count. Accounts for doors, windows, and pattern waste. Metric and imperial.

Switching units converts your existing inputs.

Room dimensions

metres

metres

metres (floor to ceiling)

Doors & windows

Default 2.0 m² per door subtracted

Default 1.5 m² per window subtracted

Roll dimensions & pattern

cm (standard 53 cm)

m (standard 10 m)

cm (enter 0 for plain / random match)

Roll presets:

How to Calculate Wallpaper Rolls

The core calculation is: work out the net wall area, divide by the usable coverage per roll, and round up. The complication is that usable coverage depends on wall height and pattern repeat — a roll that's 10 m long doesn't give you 10 m of usable strips if each strip needs to be cut longer than the wall to align a pattern.

The strip method used here is more accurate than a simple area division. It calculates how many full-height strips fit in each roll (accounting for pattern waste), then counts how many strips are needed to cover the net wall area, and divides one by the other. For a plain wallpaper on a 2.4 m wall with a 53 cm wide, 10 m long roll: strips per roll = floor(10 / 2.4) = 4. Net wall area 28 m² ÷ (0.53 × 2.4) = 22 strips needed. 22 ÷ 4 = 5.5, rounded up to 6 rolls.

Standard Roll Sizes — Metric vs Imperial

Format Width Length Gross coverage Strips @ 2.4 m wall
Metric standard53 cm10 m5.3 m²4 strips
Metric long roll53 cm15 m7.95 m²6 strips
Metric wide roll106 cm10 m10.6 m²4 strips
US standard20.5 in27 ft~36 ft²3 strips
US long roll21 in33 ft~57 ft²4 strips

Strips per roll based on plain pattern (no repeat waste). Check your product label — roll lengths vary by brand.

Pattern Repeat Waste Guide

Pattern type Typical repeat Waste per strip Extra rolls for a typical room
Plain / random match0 cmMinimal0
Small repeat10–25 cmUp to half a repeat0–1
Medium repeat25–64 cmUp to one repeat1–2
Large repeat64 cm+Can be nearly one full repeat2–3

Extra roll estimates based on a typical 4×3.5 m room with 2.4 m ceilings. Larger rooms need proportionally more allowance.

Measuring your walls accurately

Measure each wall's length at floor level and the height at the tallest point — walls are rarely perfectly square. Calculate the gross perimeter as 2 × (length + width) × height. Then subtract openings: a standard interior door is about 2.0 m² (1.0 m × 2.0 m) and a typical window is about 1.5 m² (1.0 m × 1.5 m). If you have unusually large windows, measure them individually and subtract the actual area.

For rooms with alcoves, chimney breasts, or angled walls, break the room into rectangles and calculate each section separately, then add them together. The calculator's length × width approach works well for standard rooms; for irregular rooms, use the "enter total area" approach and input your pre-calculated net wall area directly.

Frequently Asked Questions

A 10×12 ft room with 8 ft ceilings has a gross wall area of about 352 ft². Subtract one door (20 ft²) and two windows (15 ft² each) to get roughly 302 ft² of net wall area. A standard US roll at 21 in wide and 33 ft long covers about 40–45 ft² at working height, giving you 7–8 rolls for a plain pattern. Add one extra roll if you have a pattern repeat, and always buy all rolls from the same dye lot.
A large pattern repeat forces each strip to be cut longer than the wall height so the design aligns between strips. A 64 cm repeat on a 2.4 m wall means each strip uses 2.56 m of paper instead of 2.4 m, reducing strips per roll from 4 to 3. On taller walls or bigger repeats, the loss can be a full strip per roll. This calculator rounds wall height up to the next repeat interval automatically to account for this waste.
Yes, for most rooms. Subtracting standard openings gives a more accurate roll count than using gross wall area, which can over-order by one or two rolls. The exception is rooms with very small windows or many narrow wall sections between openings, where the strips above and below windows still draw from a full-height cut anyway. This calculator subtracts net opening area, which is accurate for typical residential rooms.
Buy at least one extra roll beyond the calculated total. The main reason is dye lot matching: wallpaper is printed in batches, and rolls from a different batch can have a slight colour shift that's invisible on the roll but noticeable on a finished wall. If you run short and the store is out of your batch number, you may not be able to finish the room with a consistent result. One extra roll is cheap insurance compared to the cost of redoing a wall.
Most European and Australian wallpaper is sold in rolls 53 cm wide and 10 m long, giving about 5.3 m² gross coverage. US rolls are commonly 20.5–21 inches wide and 27–33 feet long, giving roughly 36–57 ft² gross depending on the length. Both formats are supported in this calculator — enter the width and length from your roll's label for the most accurate result.
Start from a vertical plumb line near the most prominent wall — usually the one you face when entering. Work outward in both directions so any pattern mismatch ends up in a less visible corner. Avoid starting at a corner, as corners are rarely truly vertical, which causes strips to drift out of alignment as you go. Mark your starting line with a spirit level before hanging the first strip.

Wallpaper Installation Checklist

Reviewed by Natalie Green (interior decorator). Covers surface preparation, primer type by wall condition, paste selection, seam alignment, trimming at ceiling and skirting, and common mistakes that cause bubbling or peeling.

Download Checklist (PDF)

Planning reference only. See Methodology and Data Sources. View all project checklists →

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Accuracy & Review

Reviewed by: Natalie Green

Natalie is an interior decorator with experience specifying and installing wallpaper across residential renovation projects. She reviewed the strip calculation method, pattern repeat waste logic, and the roll size reference data used in this calculator.

Last updated:

See: Methodology · Data Sources · Review Board

Disclaimer: These estimates are for general planning purposes only. Actual roll quantities depend on surface condition, room geometry, installation method, and pattern matching. Always check your specific product's label for exact roll dimensions and coverage before purchasing.

See Methodology and Data Sources for calculation assumptions.