Border Calculator for Wallpaper Borders and Edging
Find how many rolls of wallpaper border or pieces of garden edging you need from the room or bed size, openings to skip, waste and roll length.
Wallpaper borders and garden edging are both sold by length, so the question is always the same: how far does the border run, and how many rolls or pieces cover it? Enter the size of the room or bed, subtract any doorways or paths where the border stops, add a waste allowance for corners and pattern matching, and the calculator rounds up to whole rolls. It also works for any perimeter you have measured yourself.
How to use this tool
- Pick feet or meters and the shape: rectangle, circle, or a total length you already measured.
- Enter the length and width (or the diameter, or the total).
- Enter the total width of doors or openings the border skips, and a waste allowance.
- Enter the length of one roll or piece and, optionally, its price.
Formula
Rolls = ⌈(P − openings) × (1 + waste ÷ 100) ÷ roll length⌉
P is the perimeter: 2 × (length + width) for a rectangle or π × diameter for a circle. ⌈ ⌉ means round up to the next whole roll, because part-rolls are not sold. The spare length is what remains after the waste allowance has been used.
Example
A 12 ft × 10 ft bedroom with one 3 ft door and a border at chair-rail height: the perimeter is 2 × (12 + 10) = 44 ft, and skipping the door leaves 41 ft. With 10% waste that becomes 45.1 ft. Rolls of 15 ft give 45.1 ÷ 15 = 3.01, so you need 4 rolls (60 ft), leaving 14.9 ft spare. Without the waste allowance three rolls would cover 41 ft on paper, leaving 4 ft for cuts and matching, slightly less than the 4.1 ft allowance requested.
Frequently asked questions
Should I subtract doors and windows?
Only where the border actually stops. A border along the ceiling line runs above doors and windows, so subtract nothing. A border at chair-rail height is interrupted by doorways, so subtract their widths.
How long is a roll of wallpaper border?
It varies by brand. Five yards (15 ft) is common in the US and many European borders come in 5 m rolls, but always use the length printed on the label.
How much extra should I allow?
About 10% covers corner cuts and pattern matching for most borders. Large repeating patterns need more, so check the pattern repeat on the label.
Does this work for garden or lawn edging?
Yes. Choose rectangle or circle for the bed, enter any path gaps as openings, and use the usable length of one edging piece after the overlap or connector.
Last updated: 2026-10-30