How to use this calculator
Measure the width of each wall you are papering and add them up, then enter the wall height. Subtract doors and windows. The coverage per roll defaults to a standard European roll (53 cm wide, 10.05 m long, about 57 ft²); US double rolls typically cover about 56 ft² and US single rolls about 28 ft² before waste — use the figure printed on the label.
The allowance defaults to 15%, which covers trimming at the ceiling and skirting and a typical pattern repeat. Use 10% for random-match or plain papers and 20–25% for repeats over 50 cm (20 in).
The formula
- P
- total width of walls to paper
- h
- wall height
- A
- wall area
- A_open
- doors & windows area
- A_net
- area to paper
- c
- coverage per roll
- w%
- pattern-match & trim allowance
- N
- rolls needed
Worked example
You are papering all four walls of a 12 × 12 ft room, 8 ft high, with standard European rolls (53 cm × 10.05 m). Doors and windows take up 40 ft².
- Wall area = 48 × 8 = 384 ft²; minus openings = 344 ft².
- Each roll covers 0.53 × 10.05 = 5.33 m² = 57.3 ft².
- Rolls = 344 × 1.15 ÷ 57.3 = 6.9, rounded up to 7 rolls.
Buy 7 rolls from the same batch (dye lot), or 8 if the pattern has a large repeat.
Common roll sizes
| Roll | Size | Coverage |
|---|---|---|
| European standard | 0.53 × 10.05 m | 5.33 m² (57 ft²) |
| US double roll | 20.5 in × 33 ft | about 56 ft² |
| US single roll | 20.5 in × 16.5 ft | about 28 ft² |
| Wide (“American”) roll | 27 in × 27 ft | about 60 ft² |
Assumptions and limits
- An area-based estimate. For very tall walls or very large pattern repeats, count drops instead: strips per roll = roll length ÷ (wall height + repeat).
- All rolls should come from the same batch number, since colors can vary between print runs.
Frequently asked questions
What is a pattern repeat?
The vertical distance after which the design repeats. Every strip has to be shifted to line up, so larger repeats waste more paper.
Should I subtract windows and doors?
Subtract large openings such as doors and big windows. Small windows can be ignored — the extra paper is useful for matching around them.
How many rolls for a feature wall?
A 12 ft wide, 8 ft high wall is 96 ft²: two European rolls with 15% allowance, or three if the repeat is large.
Sources
- Wallcoverings Association — Industry resources
- NIST Handbook 44, Appendix C — Units of length and area
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