Wallpaper Calculator

The Wallpaper Calculator helps you quickly determine how many rolls and meters of wallpaper to order for a room renovation or DIY project. Enter the room width, depth, and ceiling height in meters, then specify the number of doors and windows to deduct — and the tool instantly calculates the total wall area, net area after deductions, and the exact number of rolls required. Prevent over-ordering and plan your purchases at home centers and specialty shops with confidence.

The default settings match common Japanese wallpaper rolls: 92cm wide and 50m long. You can also switch to 53cm rolls or enter a custom width to accommodate imported wallpaper or specialty products. The overage slider (0–20%) lets you add a safety margin for cuts, pattern matching, and installation waste.

The standout feature is pattern repeat matching support. If your wallpaper has geometric patterns, stripes, or other repeating designs, enter the repeat interval in centimeters. The tool automatically adjusts the effective ceiling height so adjacent strips align perfectly at eye level — a professional-grade calculation.

Doors are assumed to be 0.9m × 2.1m and windows 0.9m × 1.2m — standard Japanese residential sizes — so the deduction calculation is both fast and realistic. The results panel shows all key metrics: total wall area, deduction area, net area, area with overage, rolls needed, and meters needed. Use these values as your reference when ordering.

All calculations happen entirely in your browser. No data is sent to any server, making it safe to use for real project planning. Ideal for pre-purchase verification before requesting contractor quotes or for budgeting your own DIY renovation.