CalculationTime

Wallpaper Calculator

Estimate wallpaper rolls from wall width, wall height, roll size, repeat allowance and openings, with the formula and printable room note kept visible.

Live math canvas

Your numbers, formula and explanation together

Wallpaper Calculator: 6 rolls. 26.8 m² measured · 30.82 m² with 15% allowance · 5.3 m²/roll · 210.00 material estimate

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Wall area = total wall width × wall height − opening area. Planning area = wall area × (1 + waste percent ÷ 100). Roll coverage = roll width × roll length. Rolls needed = ceiling(planning area ÷ roll coverage).
  1. Apply the formulaWall area = total wall width × wall height − opening area. Planning area = wall area × (1 + waste percent ÷ 100). Roll coverage = roll width × roll length. Rolls needed = ceiling(planning area ÷ roll coverage).6 rolls26.8 m² measured · 30.82 m² with 15% allowance · 5.3 m²/roll · 210.00 material estimate

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Total wall width
12 m
Add together the widths of the walls being papered.
Wall height
2.4 m
Use the finished height from skirting/top edge to ceiling or trim.
Doors/windows to subtract
2 m²
Subtract only significant openings. Many decorators keep small cutouts as allowance instead.
Roll width
0.53 m
Common European roll width is about 0.53 m. Check the roll label.
Roll length
10 m
Check the roll label before ordering.
Pattern/waste allowance
15 %
Use more for pattern repeat, trimming, mistakes, awkward walls or future repairs.
Optional price per roll
35 currency/roll
Use 0 if you only need roll quantity.

Resulting answer

6 rolls

26.8 m² measured · 30.82 m² with 15% allowance · 5.3 m²/roll · 210.00 material estimate

Answer
6 rolls
Live support
26.8 m² measured · 30.82 m² with 15% allowance · 5.3 m²/roll · 210.00 material estimate

Assumptions used

What this answer assumes

Planning estimate only. Confirm roll dimensions, pattern repeat, batch number and supplier return rules before ordering.

  • Walls are treated as a combined rectangular area; split unusual rooms into simpler wall sections before adding the widths.
  • Roll width, roll length and pattern allowance must come from the exact wallpaper product where possible.
  • The calculator rounds rolls up to whole rolls because partial rolls cannot usually be ordered as exact area.
  • Pattern repeat, batch matching, damaged strips, stairs, alcoves and professional hanging method can change the real order quantity.

Master’s Tip

How to use the result well

Master’s Tip: keep the product batch, roll width, roll length and pattern repeat beside the estimate. Wallpaper mistakes are often not arithmetic mistakes; they come from pattern matching, dye-lot changes, awkward offcuts and under-ordering one extra repair roll.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Total wall width
12 m
Add together the widths of the walls being papered.
Wall height
2.4 m
Use the finished height from skirting/top edge to ceiling or trim.
Doors/windows to subtract
2 m²
Subtract only significant openings. Many decorators keep small cutouts as allowance instead.
Roll width
0.53 m
Common European roll width is about 0.53 m. Check the roll label.

Embeddable calculator

Embed this calculator

Copy a clean iframe version with the required CalculationTime attribution link built in.

Formula

Wall area = total wall width × wall height − opening area. Planning area = wall area × (1 + waste percent ÷ 100). Roll coverage = roll width × roll length. Rolls needed = ceiling(planning area ÷ roll coverage).

Worked example

For 12 m total wall width at 2.4 m high, gross wall area is 28.8 m². Subtract 2 m² of openings to get 26.8 m². Add 15% allowance: 26.8 × 1.15 = 30.82 m². A 0.53 m × 10 m roll covers 5.3 m², so 30.82 ÷ 5.3 = 5.82 and the order estimate rounds up to 6 rolls.

Professional note

Master’s Tip: keep the product batch, roll width, roll length and pattern repeat beside the estimate. Wallpaper mistakes are often not arithmetic mistakes; they come from pattern matching, dye-lot changes, awkward offcuts and under-ordering one extra repair roll.

Regional and unit assumptions

Standard or basis: rectangular wall-area arithmetic using metric dimensions and whole-roll rounding. No manufacturer coverage guarantee, decorator quote, fire rating, paste specification or building-code approval is implied.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Wall area = total wall width × wall height − opening area. Planning area = wall area × (1 + waste percent ÷ 100). Roll coverage = roll width × roll length. Rolls needed = ceiling(planning area ÷ roll coverage).

Standard or basis

Standard or basis: rectangular wall-area arithmetic using metric dimensions and whole-roll rounding. No manufacturer coverage guarantee, decorator quote, fire rating, paste specification or building-code approval is implied.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: keep the product batch, roll width, roll length and pattern repeat beside the estimate. Wallpaper mistakes are often not arithmetic mistakes; they come from pattern matching, dye-lot changes, awkward offcuts and under-ordering one extra repair roll.

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Questions

How do I calculate how many rolls of wallpaper I need?

Multiply total wall width by wall height, subtract significant doors and windows, add a waste or pattern allowance, then divide by the coverage area of one roll and round up to a whole roll.

Should I subtract windows and doors for wallpaper?

Subtract large openings when they materially reduce wall area, but keep a practical allowance for trimming, offcuts and pattern matching. Very small openings may not reduce the order quantity.

What waste allowance should I use for wallpaper?

A simple room may use about 10% extra, while patterned wallpaper, awkward walls, stairs or novice installation can justify 15–25% or more. Use the allowance field to make that judgement visible.

Why does the calculator round up rolls?

Wallpaper is bought in whole rolls. Even if the area calculation says 5.1 rolls, the practical order estimate is 6 rolls before batch matching and supplier advice.

Does this handle pattern repeat exactly?

It handles pattern repeat as a percentage allowance, not a strip-by-strip layout. For expensive patterned paper, confirm the repeat, drop match and roll batch with the supplier or decorator.

Calculation note

Wallpaper estimating connects simple area arithmetic with a practical ordering problem. A wall can be measured in square metres, but wallpaper is bought as rolls with fixed width, length, pattern direction and batch colour. The printable report keeps the room dimensions, roll assumptions, allowance and notes together so the estimate can survive a supplier call or decorator quote.

Area is only the starting point

The calculator first treats the room as measured wall area: total wall width multiplied by wall height, minus significant openings. That gives a clean mathematical base before the order allowance is added.

Roll coverage turns area into a purchase quantity

Wallpaper rolls have a fixed width and length. Multiplying those values gives a nominal roll coverage area, but real usable coverage can be lower when patterns must align or strips need trimming.

Pattern repeat belongs in the paper trail

A plain wallpaper and a large drop-match pattern can have very different waste even in the same room. The report keeps the allowance visible instead of hiding it inside a single roll number.

Sources and further readingNIST: Metric/SI units and measurement resourcesWallcoverings Association: Wallcovering resources