Wallpaper Calculator

Determine exact wallpaper roll counts, usable strip yields, and waste allowances for straight match and half-drop pattern repeats.

Total Wall Width (Ft) Total horizontal width of all walls

Wall Height (Ft) Baseboard to ceiling

Roll Packaging Size

Pattern Vertical Repeat

Deductions for Windows / Doors (Sq Ft) Optional (many installers ignore to keep extra spare cuts)

Double Rolls to Order

7 Rolls

242 sq ft Net Surface (Includes Pattern Waste)

Full Vertical Strips 19 Strips Based on 20.5" roll width

Strips per Roll 3 Strips Accounting for pattern match

Order from the Same Dye Lot! Always buy all wallpaper rolls at the same time. Verify that the Run / Batch / Dye Lot number matches on every roll to prevent slight color shifts between panels.

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How Pattern Repeats Affect Wallpaper Yield

Unlike plain painted walls, patterned wallpaper requires matching motifs across adjacent seams. With a 21-inch vertical repeat, each vertical strip must be cut longer than the wall height to align with the adjacent panel.

Effective Cut Height = Wall Height + (Pattern Repeat in Inches / 12)
Strips per Roll = Roll Length (ft) / Effective Cut Height
Total Strips Needed = Wall Width (inches) / Roll Width (inches)

Frequently Asked Questions

Why is wallpaper sold in double rolls if priced as single rolls?

In the US, wallpaper is historically priced in "single rolls" but manufactured and shipped in continuous "double rolls" (33 feet long) to minimize scrap waste from short end-cuts.

What is a half-drop match?

A pattern where every second strip is shifted vertically by half of the pattern repeat, creating a diagonal flowing motif across the wall.

Should I subtract door and window openings?

For small windows and doors, installers recommend NOT subtracting them. The extra paper serves as an essential safety margin for dye lot matching and future repairs.