Wallpaper Calculator
Find out how many rolls of wallpaper you need. Enter your room and roll dimensions to get the roll count using the strip (drop) method decorators use — more accurate than a simple area estimate.
Wallpaper calculator
Uses the strip (drop) method decorators use. Buy an extra roll for pattern matching and mistakes, especially with a large pattern repeat. Default roll is a US double roll (20.5 in × 33 ft).
How to use it
- Enter the room length, width, and wall height.
- Enter the roll width and roll length from the product (a US double roll is 20.5 in × 33 ft).
- Read off the rolls needed, and buy one extra for pattern matching.
How it's calculated
We use the strip method: strips to go around the room = perimeter ÷ roll width; full strips you can cut per roll = roll length ÷ wall height (rounded down); and rolls = strips needed ÷ strips per roll (rounded up).
Frequently asked questions
- How many rolls of wallpaper do I need?
- Work out how many full-height strips you can cut from one roll, then how many strips it takes to go around the room, and divide. Enter your room and roll sizes above.
- Should I buy extra wallpaper?
- Yes — add an extra roll for pattern matching and mistakes, especially with a large pattern repeat. Buy from the same batch so colors match.
- How is wallpaper measured?
- By the strip (drop) method: you can't reuse the offcut at the top of each drop, so the calculator counts full strips per roll rather than raw area.
Last updated June 2026.