Wallpaper Roll Calculator – Free Calculator

Understanding the wallpaper roll calculator — concept and principle

This calculator estimates how many rolls of wallpaper you need for a room. You enter the total length of the walls you want to cover, the wall height, the roll width and length, and the pattern repeat printed on the label. Order enough at the start: rolls from different print batches can differ slightly in shade.

Only whole drops count: each 10 m roll gives three 2.55 m drops, so 34 drops need 12 rolls.

How it is calculated

Wallpaper is hung in vertical strips called drops, so the calculation counts strips rather than square metres.

Drop length: wall height plus 5 cm for trimming at top and bottom. If the paper has a pattern repeat, this length is rounded up to the next whole multiple of the repeat, so every strip can start at the same point in the pattern.
Number of drops = wall perimeter ÷ roll width, rounded up.
Drops per roll = roll length ÷ drop length, rounded down, because a leftover piece shorter than a full drop cannot be used for a full-height strip.
Rolls = number of drops ÷ drops per roll, rounded up.

The principle

Area-based estimates (wall area ÷ roll area) undercount, because each roll ends with an offcut that is too short to reuse. Counting whole drops captures that waste directly. The pattern repeat matters for the same reason: with a 64 cm repeat, a 2.55 m drop must be cut as 2.56 m (4 × 64 cm) so the motifs line up across the seams, and the extra paper is lost on every strip.

Worked example

Default inputs: perimeter 18 m, height 2.5 m, roll 0.53 m × 10 m, no pattern repeat.

Drop length = 2.50 m + 0.05 m = 2.55 m.
Drops = 18 ÷ 0.53 = 33.96, rounded up to 34.
Drops per roll = 10 ÷ 2.55 = 3.92, rounded down to 3.
Rolls = 34 ÷ 3 = 11.33, rounded up to 12 rolls.

Each point is the calculator re-run with only “Roll width (m)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Roll width (m)	Rolls
0.133	46
0.265	23
0.398	16
0.53	12
0.662	10
0.795	8
1.06	6

How to read the result

The roll count assumes you paper every metre of the perimeter, including over doors and windows. For a standard door or window you can usually leave the figure as it is, since the short pieces above and below openings use offcuts. For very large openings such as patio doors, subtract their width from the perimeter yourself. Note how sensitive drops per roll is: here 3.92 rounds down to 3, so almost a whole drop per roll is lost.

Common mistakes

Using wall area instead of counting drops, which underestimates rolls.
Ignoring the pattern repeat; large repeats can add 10–20% more rolls.
Mixing batch (lot) numbers, which can show visible colour differences.

Keep in mind: This is an estimate for flat, rectangular walls. Sloping ceilings, alcoves, half-drop patterns and offset matches can need more paper. Buy one spare roll from the same batch for repairs.

Frequently asked questions

How many rolls do I need for an average bedroom?

It depends on perimeter and height, but a room with 18 m of wall at 2.5 m high needs about 12 standard European rolls (0.53 × 10 m) with a plain paper.

What does "pattern repeat" mean?

It is the vertical distance after which the design repeats exactly. It is printed on the roll label, usually in centimetres.

Should I deduct doors and windows?

Usually not for ordinary sizes, because the offcuts cover the space above and below them. Deduct only very wide openings.

Sources: EN 233 — Wallcoverings in roll form: specification for finished wallpapers, wall vinyls and plastics wallcoverings · EN 235 — Wallcoverings: vocabulary and symbols

Checked 8 Nov 2026. Typical coverage rates and standard formulas. Always check the product label and local building rules; buy 5–10% extra for waste.

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