Check the path
Your calculation audit
Every total is shown as a short sequence so you can see what was measured, deducted, adjusted and rounded.
- 01Awaiting valid measurementsComplete the fields above to reveal the formula path.
Decorating
Wallpaper calculator
Estimate wallpaper rolls from wall dimensions, roll coverage, pattern repeat and waste.
Transparent formulaFormula v1.0 · adjusted wall area ÷ usable roll coverage
Scope boundary: Roll estimates are a planning guide; check the manufacturer's stated batch, pattern and hanging guidance.
Measure clearly
Simple guidance
Measure each wall's width and full hanging height. Keep pattern repeat separate from roll width and length; pattern matching can reduce useful coverage.
Worked example
Follow the same logic
A 4 m × 2.4 m wall less 1.8 m² of openings has 7.8 m² to cover. The tool allows for repeat and the selected waste percentage before rounding rolls up.
Planning tipWrite down the product factor or pack size you used, so a later change is easy to trace.
Before you buy
Three quick checks
- 01
Use the roll dimensions printed on the selected product.
- 02
Enter the pattern repeat whenever it applies.
- 03
Check batch codes and hanging guidance before ordering.
Quick answers
Useful to know
Why is pattern repeat important?
Matching a pattern can reduce the usable length of each drop, so a roll can cover less than its simple area suggests.
Should I deduct doors and windows?
Deduct large openings, but keep enough allowance for cutting, matching and a spare drop where appropriate.
Review record
Transparent, source-ready method
Last reviewed: 15 October 2026. Formula version: v1.0. Source/review data to be added — Calculator.Shop does not present placeholder figures as an authoritative trade specification.