Do I deduct every window?
Deduct large openings. Tiny windows and awkward corners still eat into offcuts, so keep some margin.
FAQ
Quick answers before you order the wallpaper.
Should I buy extra wallpaper?
Yes when the repeat is long, the room is awkward, or the paper may be hard to match later.
Why does pattern repeat change the roll count?
The installer loses usable drop length while lining up the print, especially on longer or staggered repeats.
Can one calculator cover the whole house?
It is safer to plan one room or one feature wall at a time when heights, windows, and repeats differ.