🖼️ Wallpaper Calculator

This wallpaper calculator estimates how many strips of wallpaper you need to go around a room, and how many rolls that translates to, based on your room's perimeter, wall height, door and window count, and roll dimensions. It's built for anyone planning a wallpapering project who wants to buy the right amount of material on the first trip to the store.

How It Works

The calculator subtracts a standard opening width for each door and window from your total room perimeter to get the effective (paperable) perimeter, since you don't paper over doorways and windows. It divides that effective perimeter by the roll width to get the number of wall-height strips needed, and separately works out how many strips fit into one roll by dividing roll length by wall height. Dividing strips needed by strips per roll — and rounding up at each step — gives the final number of rolls to buy.

Why It Matters

Wallpaper rolls are sold as whole units, and pattern repeats mean you typically can't split a roll perfectly across two different areas without waste. Knowing your strip and roll count up front — in either feet or meters — helps you avoid an awkward mid-project shortage, especially with discontinued patterns that may not be restockable.

Tips for Accurate Results

• Double-check your roll's actual width and length on the label — "standard" roll sizes vary between US, European, and specialty wallpaper brands.
• For wallpaper with a large pattern repeat, buy at least one extra roll to allow for pattern matching, which wastes some material at the top and bottom of each strip.
• Measure wall height at the tallest point of the room if your ceiling isn't perfectly level, to make sure every strip is long enough.
• Buy all rolls from the same production batch/run where possible, since wallpaper color can vary slightly between runs.