Wallpaper Calculator
Estimate wallpaper rolls from wall size, roll dimensions, pattern repeat, openings, trim allowance, and waste.
Use room perimeter when you know the room size, total wall width for selected walls, or known wall area when the area is already measured.
Results
This estimates wallpaper rolls for simple walls and rooms. It does not price installation, removal, adhesive, or wall preparation.
How to use this calculator
- 01Choose room perimeter, total wall width, or known wall area.
- 02Enter the wall size, opening deduction, roll width, and roll length.
- 03Add pattern repeat, trim allowance, and waste percentage if they apply.
- 04Use the rolls needed row as the main ordering estimate and review the drops per roll.
If you need to find wall area first, use the Square Footage Calculator. For metric-first area inputs, use the Square Meter Calculator.
Understanding the math
When wall width and height are known, the calculator estimates wallpaper by strips. It rounds each drop for trim and pattern repeat, finds how many drops fit on a roll, then adds waste.
total_wall_width = 2 x (room_length + room_width) drop_length = wall_height + trim_allowance adjusted_drop = ceiling(drop_length / pattern_repeat) x pattern_repeat drops_per_roll = floor(roll_length / adjusted_drop) drops_needed = ceiling(net_wall_width / roll_width) rolls_needed = ceiling(ceiling(drops_needed / drops_per_roll) x waste_factor) known_area_rolls = ceiling((wall_area - openings) / roll_coverage x waste_factor)
Known wall area mode uses area coverage. Pattern-repeat roll counts are more exact when wall height is known because repeat affects each vertical drop, not just the total m² or square footage.
Wallpaper roll reference table
Use these active-unit examples as a quick check for common roll sizes, drop counts, repeat allowance, and opening deductions.
| Example | Result | Note |
|---|---|---|
| 20.5 in x 33 ft roll | about 56 sq ft | Before repeat and waste |
| 10 ft high wall, no repeat | 3 drops per 33 ft roll | With 4 in trim allowance |
| 10 ft high wall, 12 in repeat | 3 drops per 33 ft roll | Drop rounds to repeat |
| 20 sq ft opening | subtract 20 sq ft | Door or window deduction |
Frequently asked questions
How to calculate wallpaper?
Measure the wall width or area, subtract openings if needed, then compare the net wall area and strip count against the roll width, roll length, pattern repeat, and waste.
How to calculate square footage for wallpaper?
Multiply wall width by wall height, subtract doors or windows if needed, and add each wall together.
How do you calculate wallpaper with pattern repeat?
Add trim allowance to the wall height, then round each drop up to the next pattern repeat before calculating how many drops fit on a roll.
How many sq ft is in a single roll of wallpaper?
A common US roll is about 20.5 inches wide by 33 feet long, or roughly 56 sq ft before pattern matching and waste.
Can I use this calculator with metric measurements?
Yes. Use the Imperial/Metric toggle. Inputs, results, reference values, and examples follow the active unit system.