Wallpaper roll calculator

How to use the wallpaper roll calculator

Estimate the wallpaper rolls needed for walls using total wall length, height, openings, roll dimensions and pattern matching. It works in feet and inches or metres and centimetres.

1. Choose Feet / inches or Metres / cm under Units.
2. Enter the total wall length to paper and Wall height.
3. Enter the total area of doors and windows in Openings to deduct, or leave it at 0.
4. Enter the Pattern repeat and choose Free match, Straight match or Drop match.
5. Open Show advanced: Roll size if your roll width, length or trim allowance differs from the defaults, then review the roll and strip totals.

What to enter

Units

Choose Feet / inches for imperial measurements or Metres / cm for metric measurements. The default is Feet / inches.

Total wall length to paper

Add the widths of all walls you will paper. Enter feet by default; the default is 52 ft. Metric input uses metres.

Wall height

Enter the wall height in feet by default; the default is 8 ft. Metric input uses metres.

Openings to deduct

Enter the combined door and window area. Use sq ft by default; the default is 0 sq ft. Metric input uses m². Leave 0 to make no deduction.

Pattern repeat

Enter the printed vertical repeat from the wallpaper label. Use inches by default; 0 means no repeat. Metric input uses cm.

Match type

Choose Free match (no alignment), Straight match or Drop match (half-drop). The default is Free match.

Roll width

Enter the roll width in inches by default; the default is 20.5 in. Metric input uses metres, with a default of 0.53 m.

Single-roll length

Enter the length of one single roll in feet by default; the default is 33 ft. Metric input uses metres, with a default of 10.05 m.

Trim allowance per strip

Enter extra length cut at the top and bottom of each strip. The default is 4 in. Metric input uses cm, with a default of 10 cm.

Default imperial example

Use 52 ft of total wall length, an 8 ft wall height, 0 openings, a 0 in pattern repeat, Free match, the default 20.5 in roll width, the default 33 ft single-roll length and 4 in trim. Convert the wall measurements: 52 ft × 12 = 624 in and 8 ft × 12 = 96 in. Each strip is 96 in + 4 in = 100 in. One roll is 33 ft × 12 = 396 in, so 396 in ÷ 100 in = 3.96; floor to 3 strips per roll. Around the walls, 624 in ÷ 20.5 in = 30.439..., so the calculator rounds up to 31 gross strips. With 0 openings, 20.5 in × 96 in = 1,968 sq in per full-height strip area and 0 ÷ 1,968 = 0 saved strips, leaving 31 strips needed. Rolls needed are 31 ÷ 3 = 10.333..., rounded up to 11 single rolls. Double rolls are 11 ÷ 2 = 5.5, rounded up to 6 double rolls. The last roll has 11 × 3 = 33 strip spaces; 33 − 31 = 2 spare strips, so one extra roll is optional. Paper area is 11 × 396 × 20.5 = 89,298 sq in. Wall area is 624 × 96 = 59,904 sq in. Waste is (89,298 − 59,904) ÷ 89,298 × 100 = 32.916..., displayed as 32.9%.

How the roll estimate is computed

The calculator converts entered lengths to inches for the calculation. Strip cut length starts with wall height + trim allowance. With Free match, the pattern repeat does not change strip length. With Straight match, cut length is rounded up to the next whole pattern repeat. With Drop match, the calculator adds half a repeat after that rounding. Strips per roll = floor(single-roll length ÷ strip length). If fewer than one strip fits on a roll, the calculator shows an error. Gross strips = ceil(total wall length ÷ roll width). Openings are converted to square inches. Saved strips = floor(openings area ÷ (roll width × wall height)), limited to no more than gross strips − 1. Strips needed = the greater of 1 or gross strips − saved strips. Single rolls = ceil(strips needed ÷ strips per roll). Double rolls (US retail) = ceil(single rolls ÷ 2). The extra-roll recommendation is yes when the final rolls leave fewer than two spare strips or when the match type is Drop match. Waste is calculated from the difference between the paper area (single rolls × roll length × roll width) and wall area after the opening deduction, divided by paper area. The displayed strip length and waste percentage are rounded to one decimal place.

Reading the results

The main result shows Single rolls. The breakdown also shows Double rolls (US retail), Strips needed, strips per roll, gross strips, strips saved by openings, spare strips in the last roll and Waste. Buy the displayed single-roll quantity, or use the double-roll quantity when shopping in US retail units. Buy one extra roll when the result says yes; this recommendation is separate from the calculated roll totals. A double roll is treated as two single rolls for the calculation.

Limitations and common mistakes

• The calculator cuts every strip at full wall height from a fresh length. It does not reuse partial strips.
• Openings are deducted only as whole full-height strip equivalents, so the deduction is conservative.
• The calculation uses total wall length and opening area. It does not place doors, windows, corners or other obstacles on individual walls.
• Roll packaging, usable selvage and product-specific instructions can differ. Check the roll label before buying. Buy from the same batch and keep a spare roll for repairs if needed.

Frequently asked questions