How many rolls you need — with pattern repeat & waste
Add each wall's width separately. Strips are rounded up per wall — they don't wrap around corners cleanly, so this orders a little more than the perimeter method.
Using a non-standard roll, a tighter tolerance, or want a cost estimate? Open Roll specs to set roll width, length, safety margin and price.
Roll specs, openings & price
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Wallpaper to order
0 rolls
0 strips
Buy all rolls in one order and confirm they share the same batch / dye-lot number — reorders rarely match.
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Wallpaper Calculator — guide & how to use
What it does
This wallpaper calculator works out how many rolls to order for a room —
not from plain area, but from how many vertical strips (drops) you can actually hang and how
many you get out of each roll once you account for the pattern repeat. It adds a safety
buffer, reports the answer in the unit the store really sells (double rolls in the US), and gives an optional
cost estimate. Calculated privately in your browser, free.
How to use it
Pick a method: Whole room (enter the total perimeter) or Wall-by-wall (add each wall's width). Wall-by-wall rounds strips up on every wall, since a strip can't wrap a corner — useful when you're skipping a feature wall or want the safest count.
Enter your room perimeter (sum of all wall widths) and wall height.
Pick the pattern match type and enter the pattern repeat from the roll label (leave 0 for plain / free-match paper).
Open Roll specs to set the roll's usable width, length, the unit the store sells, your safety margin, doors/windows and an optional price.
Read the rolls to order, the strip and waste breakdown, and the cost.
Worked example
A 10×10 ft room has a 40 ft perimeter and 8 ft walls. The paper is a
straight match with a 20.5 in repeat, on double rolls that are
20.5 in wide × 33 ft long, with a 10% safety margin:
Strip length = 8 ft (96 in) + 4 in trim = 100 in.
Straight-match waste = one repeat = 20.5 in, so each strip is produced at 100 + 20.5 = 120.5 in.
Strips per roll = floor(396 in ÷ 120.5 in) = 3 strips.
Strips needed = ceil(480 in perimeter ÷ 20.5 in width) = 24 strips.
Raw rolls = ceil(24 ÷ 3) = 8; with 10% margin = ceil(8 × 1.10) = 9 double rolls.
Notice that a plain "area ÷ coverage" shortcut would have under-ordered here — the 20.5 in repeat quietly
added a whole extra roll.
Accuracy notes & disclaimer
This is an estimate for ordering, not an exact cut list. The strip method intentionally over-estimates (worst-case repeat waste, full-height strips over doors/windows) because running short forces a reorder that may not match the dye lot.
The repeat-waste model is conservative: it assumes up to one full repeat lost per strip (straight match) or about 1.5× the repeat (half-drop). A skilled hanger nesting offcuts may use slightly less — never assume less when ordering.
Default roll sizes: US single roll ≈ 20.5–21 in × 16.5 ft; US double roll ≈ 33 ft (the unit actually sold); Euro roll ≈ 0.53 m × 10.05 m. Always confirm the exact width, length and repeat on your specific product's label — they vary by manufacturer.
Printed "coverage" figures (≈56–60 sq ft per US double roll) bake in some trim but not your pattern repeat or wall geometry, which is why an area-only shortcut under-orders for big repeats.
Not a substitute for a professional measure on staircases, slopes, irregular rooms or feature walls. Murals and panel sets are sold by the panel, not the roll — this tool doesn't apply to them.
Frequently asked questions
How many rolls of wallpaper do I need?
Strips needed across the room (perimeter ÷ usable width, rounded up) ÷ strips per roll (roll length ÷ strip length after pattern matching, rounded down), rounded up, plus a 10–15% safety margin. This tool does it all and accounts for pattern repeat.
How does pattern repeat change the amount?
Each strip is cut on a repeat boundary, so up to one full repeat is wasted per strip (≈1.5× on half-drop). A 20+ in repeat can add 30–50% more paper — the #1 reason people run short.
Single roll vs double roll — which do I buy?
US labels quote single-roll coverage but stores sell double rolls (~33 ft). This tool reports the answer in the sold unit so you don't double or halve the order.
How much extra should I order?
Add 10–15% on top of repeat waste for trimming errors and a spare for patch repairs. Reorders rarely match the dye lot, so buy everything in one order and check the batch numbers match.
Why is this more than plain area suggests?
Because you can only hang whole strips and each loses paper to the pattern repeat. The strip method is deliberately conservative so you don't run short mid-job.
Is it really free?
Yes. 100% free, everything runs in your browser. A free account is only needed if you want to download or save your result.