# Wallpaper Calculator and Cost Estimator

## Using the Wallpaper Calculator to Estimate the Number of Rolls Needed

The wallpaper calculator estimates the number of rolls of wallpaper a project will require. Enter the dimensions of the room and usable square footage of wallpaper per roll and the calculator will estimate the number of rolls you need to purchase. Optionally, enter a price per roll and the calculator can estimate the cost of the materials.

The wallpaper calculator is very powerful tool to estimate wallpaper material for do-it-yourselfers and professionals alike!

Estimating wallpaper needed for a project involves finding the square footage of the surfaces to be wallpapered, determining the usable wallpaper per roll, then calculating how many rolls of wallpaper will be needed to cover the room’s square footage. Square footage the measurement of a space in feet. You can find a wall’s square footage by measuring the wall’s length times the wall’s height, ie. a 12 ft wide by 9 ft high wall is 12 x 9 = 108 sq ft. Make sure length, width, and height measurements are in feet before you multiply to find the square footage, it may be easiest to round your measurements to avoid working with inch fractions and decimals.

If your walls are not simple rectangles or are complex then you can split up the wall into smaller chunks and find the square footage of each part separately, then add the square footage measurements together. For example, if your wall is not a simple rectangle, break it into different sections and measure the square footage of each section and add the different sections together.

Once you know the square footage of all the walls, add all the square footages together to find the total project square footage.

The next step is to find the usable square footage for your chosen wallpaper. Different wallpaper patterns have different amounts of usable square footage, which is determined by the drop pattern. The reason for this is that when you drop the next section of wallpaper to align the patterns there will be waste that needs to be cut to make the pattern line up. That waste reduces the usable square footage of the roll. The following are estimates of the coverage of different drop patterns.

- A standard US wallpaper roll with no pattern will cover 36 square feet, a standard European roll will cover 29 square feet
- A 0-6 inch drop pattern will have 25 usable square feet
- A 7-12 inch drop pattern will have 22 usable square feet
- A 13-18 inch drop pattern will have 20 usable square feet
- A 19-23 inch drop pattern will have 15 usable square feet

Once you know the usable square footage per roll of wallpaper you can find the number of rolls needed by dividing the total square footage by the usable square footage per roll. For example, if your room has 350 square feet of walls that need to be wallpapered, and each roll has 25 usable square feet, the number of rolls needed is 350 / 25 = 14 rolls.

It may be a good idea to order 10-20% extra paint to allow for cutoffs and waste material. If you are fairly close to an even roll then it may be a good idea to order an extra roll to ensure you are not short on material. It is worth finding out the return policy and if a return is simple then ordering extra material can ensure you are not short and allow you to simply return any excess material.

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