# Wallpaper Calculator

> Add each wall, then your roll width, roll length and pattern repeat. The calculator counts strips per wall, cuts each strip to a whole repeat, finds strips per roll and gives the rolls to order. Four walls of 12 and 10 ft need 10 rolls, so order 11.

Canonical: https://receiptscanner.co/tools/wallpaper-calculator
Updated: 2026-10-28 · Sources re-checked by: 2027-10-28

This is a free interactive calculator that runs in the browser. Nothing you type is stored or sent. Results are estimates.

## How it works

Strips for a wall = wall width ÷ roll width, rounded up. Cut length = the tallest wall height + trim (for the top and bottom), rounded up to a whole number of pattern repeats. Strips per roll = roll length ÷ cut length, rounded down, because a strip cannot be joined across the end of a roll. Rolls = total strips ÷ strips per roll, rounded up. Rolls to order = rolls plus a spare allowance, rounded up. Doors and windows are not taken off the strips, because the paper above and below them is still needed.

**Strips per roll for an 8 ft wall (4 in trim) on a 33 ft roll, by pattern repeat**

| Pattern repeat | Cut length | Strips per roll |
| --- | --- | --- |
| None (straight) | 100 in | 3 |
| 12 in | 108 in | 3 |
| 18 in | 108 in | 3 |
| 24 in | 120 in | 3 |
| 32 in | 128 in | 3 |

**Typical roll sizes**

| Roll | Width | Length | Area |
| --- | --- | --- | --- |
| US double roll | 20.5 in | 33 ft | about 56 sq ft |
| US single roll | 20.5 in | 16.5 ft | about 28 sq ft |
| European roll | 21 in | 33 ft | about 58 sq ft |

## Worked example: four walls of 12, 10, 12 and 10 ft, 8 ft high, a 12 in repeat

1. Strips: 12 ft = 144 in ÷ 20.5 = 7.02, so 8. 10 ft = 120 in ÷ 20.5 = 5.85, so 6. In all 8 + 6 + 8 + 6 = 28.
2. Cut length: 96 in wall + 4 in trim = 100 in, up to a whole repeat of 12 in = 108 in.
3. Strips per roll: 33 ft = 396 in ÷ 108 = 3.67, so 3.
4. Rolls: 28 ÷ 3 = 9.33, so 10 rolls.
5. With a 10% spare allowance order 11 rolls. With no pattern repeat the answer is also 10, because the cut length is 100 in and 3 still fit.

## FAQ

### How many rolls of wallpaper do I need?
Count the strips each wall needs, work out how many strips come from one roll, and divide. This page does it with your roll size and pattern repeat, which is more reliable than dividing areas.

### What is a pattern repeat?
The vertical distance before the pattern starts again. Each strip has to be cut to a whole number of repeats so the pattern lines up from one strip to the next, which wastes some paper.

### Why not just divide the wall area by the roll area?
Because strips are cut in full lengths. Offcuts at the ends of rolls often cannot be used, especially with a repeat, so an area division can leave you short.

### Should I subtract doors and windows?
Not from the strips. The paper above a door and below a window is still needed, so the calculator counts full strips across every wall. The spare allowance covers the rest.

### What are the sizes of wallpaper rolls?
A US double roll is about 20.5 in wide and 33 ft long, a single roll is half that. European rolls are about 21 in wide. Check the label, because roll sizes differ by maker.

### How many spare rolls should I order?
About 10% is common, and a large or drop-match pattern may need more. Rolls from the same print run match in color, so order everything together.

## Sources

- [European rolls vs double rolls: typical roll sizes in inches (a US double roll is about 20.5 in by 33 ft)](https://www.selectedwallpapers.com/pages/european-rolls-vs-double-rolls) (checked 2026-10-28)
- [Wallpaper: how it is made, pattern repeats and matching](https://en.wikipedia.org/wiki/Wallpaper) (checked 2026-10-28)

This calculator is an estimate for planning. Roll sizes and pattern matching vary by product, so check the label and ask your supplier before you order, and buy all rolls from one batch.