Wallpaper calculator
Count whole drops for one wall, with free or straight matching.
Formula
Drop = height rounded up to a repeat; rolls = ceil(strips / floor(roll length/drop))
Wall width: 12 ft · Height including trim: 9 ft · Roll width: 20.5 in · Usable roll length: 33 ft · Straight pattern repeat: 0 in · Cut length per strip ≈ (9 ft × 0.3048 m/ft) · Strips needed ≈ ceil(((12 ft × 0.3048 m/ft)÷(20.5 in × 0.0254 m/in))×(1-8.881784197001252e-16)) · Strips per roll ≈ floor(((33 ft × 0.3048 m/ft)÷(2.7432))×(1+8.881784197001252e-16)) · Physical rolls ≈ ceil(((8)÷(3))×(1-8.881784197001252e-16))
How to use
- Enter wall width and height including trimming.
- Enter physical roll size; repeat 0 means free match.
- Read rolls; buy any additional spare rolls separately.
Examples
- 4 m wide, 2.5 m drops and 0.5 × 10 m rolls need 2 rolls.
Frequently asked questions
What about windows?
Keep the full wall width: short pieces around openings are not reused here.
Does it handle offset patterns?
No. Half-drop, offset and paired-roll patterns need a product-specific plan.
Why can a roll be unusable?
A roll shorter than one full drop cannot be used. Initial pattern alignment must be included in the usable roll length.
Sources
Updated: