Calculating how much wallpaper you need is one of the most common questions we get at Peel & Pattern — and one of the most important to get right. Order too little and you'll run short mid-project; order too much and you'll waste money. This guide gives you the complete calculation method with worked examples for every common scenario.
What You Need to Know Before You Calculate
Before calculating, you need three pieces of information:
- Your wall dimensions: The width and height of each wall you plan to wallpaper. See our How to Measure for Wallpaper guide.
- The wallpaper roll dimensions: The width and length of each roll. Our standard rolls are 52cm wide × 10m long.
- The pattern repeat: The vertical distance between repeating elements of the pattern. This is listed on every product page.
The Basic Calculation (No Pattern Repeat)
For plain or textured wallpaper with no pattern repeat:
- Calculate total wall area: add together (width × height) for each wall.
- Calculate usable area per roll: roll width × roll length.
- Divide total wall area by usable area per roll.
- Round up to the nearest whole number.
- Add 10% safety margin (round up again).
Example: Four walls each 3.5m wide × 2.4m high = 33.6m² total. Roll = 0.52m × 10m = 5.2m² per roll. 33.6 ÷ 5.2 = 6.46 → round up to 7 rolls. Add 10% → 8 rolls.
Calculating for Pattern Repeat
When your wallpaper has a pattern repeat, each strip must be cut longer than the wall height to allow for matching the pattern. This means you get fewer usable strips per roll.
Step 1: Calculate the Cutting Length Per Strip
Cutting length = wall height + pattern repeat.
Example: Wall height 2.4m, pattern repeat 30cm (0.3m). Cutting length = 2.4 + 0.3 = 2.7m per strip.
Step 2: Calculate Strips Per Roll
Strips per roll = roll length ÷ cutting length (round down to whole number).
Example: Roll length 10m ÷ 2.7m cutting length = 3.7 → round down to 3 strips per roll.
Step 3: Calculate Total Strips Needed
Total strips needed = total wall width ÷ wallpaper roll width (round up to whole number).
Example: Total wall width (all four walls) = 14m. Roll width = 0.52m. 14 ÷ 0.52 = 26.9 → round up to 27 strips.
Step 4: Calculate Rolls Needed
Rolls needed = total strips ÷ strips per roll (round up to whole number).
Example: 27 strips ÷ 3 strips per roll = 9 rolls. Add 10% safety margin → 10 rolls.
Quick Reference: Rolls Needed by Room Size
These are approximate figures for a standard room with 2.4m ceilings and no pattern repeat:
- Small bedroom (3m × 3m): approximately 6–7 rolls for all four walls.
- Standard bedroom (4m × 3.5m): approximately 8–9 rolls for all four walls.
- Large bedroom / living room (5m × 4m): approximately 10–12 rolls for all four walls.
- Accent wall only (3.5m wide × 2.4m high): approximately 2 rolls.
- Powder room (1.5m × 1.5m): approximately 2–3 rolls for all four walls.
Always add 10–20% for pattern repeat and safety margin.
Common Mistakes to Avoid
- Not accounting for pattern repeat: The most common calculation error. Always check the pattern repeat on the product page and add the appropriate allowance.
- Not adding a safety margin: Always add at least 10% extra. Running short of wallpaper mid-project is one of the most frustrating wallpaper experiences.
- Measuring only once: Always measure twice and use the larger measurement.
- Forgetting to measure all walls: If wallpapering a full room, measure all four walls — they are rarely all the same width.
When in Doubt, Order More
If you're between roll quantities, always order the higher number. Having one extra roll is far better than running short. Unused rolls can be kept for future repairs.
Frequently Asked Questions
What is a pattern repeat and why does it matter?
A pattern repeat is the vertical distance between identical points in a repeating pattern. When hanging wallpaper with a pattern repeat, each strip must be cut longer than the wall height to allow the pattern to align at the seams. The larger the pattern repeat, the more wallpaper is wasted in trimming, and the more rolls you need.
Do I need to account for doors and windows?
You can subtract large door and window openings from your total wall area, but many professionals recommend not doing so — the offcuts from around openings are often needed for pattern matching. If you do subtract, only subtract openings larger than 1m².
Ready to Order?
Browse our full wallpaper collection and use our calculator at checkout. If you're unsure about color or pattern, order a sample first. See our Wallpaper Sample Buying Guide.