Use this free wallpaper calculator to find how many wallpaper rolls you need in seconds. Enter your wall size in metres or feet, choose a roll size, and the wallpaper calculator rounds up and adds extra for pattern matching and waste instantly — no sign-up, no account, and no personal information needed. Your numbers are calculated in your browser and are not sent to us.
Contents: Formula · How to use · Examples · Tips · FAQ · Related tools
No sign-up required. This wallpaper calculator works in your browser, so the dimensions you enter are not stored or sent to us. Buy all rolls from the same batch so the pattern and colour match.
Wallpaper Calculator Formula
This wallpaper calculator divides the wall area by the usable area of one roll, then rounds up to a whole roll, because you cannot buy part of a roll. It then adds your chosen percentage for pattern matching and waste, and rounds up again.
Wall area = Wall length × Wall height
Rolls needed = Round up ( Wall area × (1 + Waste ÷ 100) ÷ Area of one roll )
For example, a wall 4 m × 2.5 m is 10 square metres. A 0.53 m × 10 m roll covers 5.30 square metres. With 10% extra: 10 × 1.10 ÷ 5.30 = 2.08, which rounds up to 3 rolls. If you enter feet, the wallpaper calculator converts the area to square feet for inch rolls, or to square metres for metric rolls.
How to Use the Wallpaper Calculator
Measure the length and height of the wall, then type them into the first two boxes and choose metres or feet. Choose your roll size from the list, set the extra for pattern matching and waste (10% is a good default, 15% is safer for large patterns), and tap Calculate Wallpaper Rolls. For more than one wall, add the wall areas together first, or run the wallpaper calculator once per wall and add the rolls.
Subtract large windows and doors from the wall area only if they are very large; for small openings, keep them in the area, because the extra paper helps with pattern matching around them.
Wallpaper Calculator Examples
Example 1 — 4 m × 2.5 m wall, 0.53 m × 10 m roll, 10% waste. Area 10 sq m; 10 × 1.10 ÷ 5.30 = 2.08, rounded up to 3 rolls.
Example 2 — 5 m × 2.5 m wall, 0.53 m × 10 m roll, 10% waste. Area 12.5 sq m; 12.5 × 1.10 ÷ 5.30 = 2.59, rounded up to 3 rolls.
Example 3 — 12 ft × 8 ft wall, 20.5 in × 33 ft roll, 10% waste. Area 96 sq ft; 96 × 1.10 ÷ 56.4 = 1.87, rounded up to 2 rolls.
These wallpaper calculator examples show why rounding up matters: a result of 2.08 rolls means 2 rolls would leave part of the wall uncovered.
Wallpaper Calculator Tips
Check the pattern repeat on the roll label: a large repeat needs more extra paper than a small repeat or a plain paper. Buy all rolls from the same batch number, and keep one spare roll for future repairs. For background on wallpaper types and history, see Wikipedia’s article on wallpaper.
Wallpaper Calculator FAQ
What does a wallpaper calculator do? A wallpaper calculator finds how many rolls you need for a wall from the wall size and the roll size, rounded up and including extra for pattern matching and waste.
Why does the wallpaper calculator round up? Because rolls are sold whole. A result of 2.08 rolls must become 3 rolls, or part of the wall would stay uncovered.
How much extra should I add for waste? 10% is a good default for small patterns. Use 15% for large patterns, or for walls with many corners and openings.
Can I use feet and inches? Yes. Enter the wall in feet and choose an inch roll size, and the wallpaper calculator works in square feet. Enter the wall in metres for metric roll sizes.
Should I subtract windows and doors? Subtract very large openings, but keep small ones in the area, because the extra paper helps with pattern matching.
How do I work out rolls for more than one wall? Add the wall areas together first, or run the wallpaper calculator once per wall and add the rolls.
Related Tools
Try the Tile Calculator for floors, the Roof Calculator for roofing area, the Percentage Increase Calculator to measure a change, and the Discount Calculator to find a sale price. Return to the PDGPT homepage to browse all free calculators by category.
Sources and Method
Method: this page uses its own Wallpaper Calculator Formula. Wall area = Wall length × Wall height, and Rolls needed = Round up ( Wall area × (1 + Waste ÷ 100) ÷ Area of one roll ). The result is rounded up because rolls are sold whole, and the waste allowance covers pattern matching and waste. No external source is used for this calculation.
Last updated: October 28, 2026