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Wallpaper Calculator

Rolls required for a room. Free online Wallpaper Calculator. Calculate wallpaper online — fast, accurate, mobile-friendly, no signup needed.

Rolls
6

Derivation

  1. ├── 01Givenperimeter = 40, h = 8, roll = 56
  2. ├── 02Formulaceil(t × a / n)
  3. └── 03Compute Rolls6
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§01What is

Understanding the Wallpaper Calculator

The Wallpaper Calculator computes Rolls from 3 inputs: room perimeter (ft), wall height (ft), roll coverage (ft²). Rolls required for a room.

On a construction site, estimates that come in 10% off add up to six-figure overruns. Running the quantities with a calculator instead of a rule-of-thumb gets you closer to the truth with zero extra effort. The Wallpaper Calculator sits in that toolkit — it rolls required for a room. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

ceil(t × a / n)

Where

perimeter
Room perimeter (ft)
h
Wall height (ft)
roll
Roll coverage (ft²)
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: Room perimeter (ft) = 40, Wall height (ft) = 8, Roll coverage (ft²) = 56.

  1. 01Start by noting the input — Room perimeter (ft): 40.
  2. 02Start by noting the input — Wall height (ft): 8.
  3. 03Start by noting the input — Roll coverage (ft²): 56.
  4. 04Substitute these values into the formula: ceil(t × a / n)
  5. 05Compute Rolls: the calculator returns 6.
  6. 06Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Wallpaper Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

Room perimeter (ft) halved

perimeter = 20 (from 40)

Keep every other input at its default and halve the room perimeter (ft). See how rolls responds.

  1. 01New Room perimeter (ft): 20
  2. 02Baseline Rolls: 6
  3. 03New Rolls: 3
  4. 04Rolls decreases by 50% → use this sensitivity to plan for real-world variation.
02 · PATTERN

Room perimeter (ft) doubled

perimeter = 80 (from 40)

Keep every other input at its default and double the room perimeter (ft). See how rolls responds.

  1. 01New Room perimeter (ft): 80
  2. 02Baseline Rolls: 6
  3. 03New Rolls: 12
  4. 04Rolls increases by 100% → use this sensitivity to plan for real-world variation.
03 · PATTERN

Wall height (ft) halved

h = 4 (from 8)

Keep every other input at its default and halve the wall height (ft). See how rolls responds.

  1. 01New Wall height (ft): 4
  2. 02Baseline Rolls: 6
  3. 03New Rolls: 3
  4. 04Rolls decreases by 50% → use this sensitivity to plan for real-world variation.
04 · PATTERN

Wall height (ft) doubled

h = 16 (from 8)

Keep every other input at its default and double the wall height (ft). See how rolls responds.

  1. 01New Wall height (ft): 16
  2. 02Baseline Rolls: 6
  3. 03New Rolls: 12
  4. 04Rolls increases by 100% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
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