Wallpaper Calculator
Wallpaper math is unforgiving: pattern repeats eat length, and rolls cannot be split across walls. This wallpaper calculator converts your total wall length into full-width strips, lengthens each strip for the pattern repeat, and divides by what each roll actually yields. It handles US single, US double, and European rolls, so the number you get is the number to buy.
Add up the lengths of all walls to be papered
Floor to ceiling at the tallest point
Coverage is a rule of thumb — check the label
Rolls needed
4
- Wall strips needed2-ft-wide strips (rule of thumb)
- 10
- Full strips per roll
- 3
How it was calculated
- Strips = ceil(20 ft ÷ 2 ft) = 10
- Strip length = 8 ft × 1.00 = 8.0 ft
- Roll length = 56 ft² ÷ 2 ft = 28.0 ft → 3 full strip(s) per roll
- Rolls = ceil(10 ÷ 3) = 4
How it works
Strips first: wallpaper hangs in vertical strips, and this calculator assumes 2-ft-wide strips (a rule of thumb — check your roll’s actual width). Strips = ceil(total wall length ÷ 2).
Each strip must run floor to ceiling plus pattern-match waste: strip length = wall height × (1 + waste). No repeat means 0%, a small (~12 in) repeat about 10%, and a large (~24 in) repeat about 20% — all rules of thumb.
Roll yield: roll length = roll coverage ÷ 2 (same 2-ft width assumption), so a 56 ft² double roll gives 28 ft of strips. Strips per roll = floor(roll length ÷ strip length) — only full strips count.
Rolls = ceil(strips ÷ strips per roll). Partial rolls cannot be bought, and strips cannot be spliced across walls.
Worked examples
20 ft of wall, 8 ft high, US double roll, no repeat
Strips: 20 ÷ 2 = 10. Strip length: 8 ft × 1.00 = 8 ft. Roll length: 56 ÷ 2 = 28 ft → 28 ÷ 8 = 3.5 → 3 full strips per roll. Rolls: 10 ÷ 3 = 3.33 → 4 rolls.
24 ft of wall, 9 ft high, European roll, large repeat
Strips: 24 ÷ 2 = 12. Strip length: 9 × 1.20 = 10.8 ft (20% pattern waste). Roll length: 53 ÷ 2 = 26.5 ft → 26.5 ÷ 10.8 = 2.45 → 2 strips per roll. Rolls: 12 ÷ 2 = 6 rolls.
How to measure
- Add up the full length of every wall getting paper — measure each wall separately and sum them.
- Measure height floor to ceiling at several spots; old houses slope, so use the tallest reading.
- Do not subtract doors and windows from the length — the waste around openings roughly equals the saving.
- Check your roll’s actual width and length on the label; "double roll" is not perfectly standardized.
- Note the pattern repeat printed on the roll (often in inches or cm) to pick the right waste tier.
Assumptions & limitations
Planning estimate
- Strips are assumed 2 ft wide and roll length is derived as coverage ÷ 2 — both rules of thumb; real rolls are often ~20.5 in (US) or ~21 in (EU) wide.
- Pattern waste tiers (0/10/20%) are rules of thumb; an exact repeat measurement beats the tier.
- Openings are not deducted — framing cuts around doors and windows consume roughly what you would save.
- Buy one extra roll beyond the result for future repairs; dye lots change.
Frequently asked questions
Divide the wall’s length by 2 to get strips (each strip is assumed 2 ft wide), then see how many full strips your roll yields after pattern waste. A 10-ft wall needs 5 strips; a US double roll at 8-ft ceilings with no repeat gives 3 strips per roll, so you would buy 2 rolls. The calculator above does this in one step.
Pattern repeat is the vertical distance before the design starts over — printed on every roll. Each strip must be cut so the pattern aligns with its neighbor, which means trimming off the non-aligning portion; larger repeats waste more. As a rule of thumb, allow 10% extra for a small (~12 in) repeat and 20% for a large (~24 in) repeat.
A US single roll covers about 28 ft² and a double roll about 56 ft² — double rolls are simply twice the length, not twice the width. European rolls are a different standard at about 53 ft². Coverage varies slightly by manufacturer, so always check the label and select the matching roll type above.
No — and this surprises people. The paper you would "save" over an opening gets consumed by the extra cutting and matching around its frame. Pros measure the full wall length and let the waste allowance absorb the openings. Only skip a wall entirely if it gets no paper at all.
Wallpaper dye lots shift between print runs, so a roll bought next year may not match. One spare roll covers future repairs — a torn strip, a stained section — with an exact match. Store it sealed, upright, in a dry place, and note the lot number.