There's nothing more frustrating for a do-it-yourself paperhanger than to run out of wallpaper just a few feet short of finishing a project. Proper measuring and calculating at the outset of a project can eliminate that frustration.

Here are some tips for estimating rollage:

Step 1:

Measure Accurately.

Whether you do the calculations yourself or have a retail salesperson help you, the first step is to have accurate measurements. Use a yardstick or steel tape measure, never a cloth tape measure. Take measurements in feet, rounding off to the next highest half foot or foot.

Next, draw a room diagram, showing ceiling height, doors, windows, fireplaces, built-in bookcases and the like. Measure wall height from floor to ceiling, excluding baseboards and moldings. Measure length of each wall, including doors and windows. If hanging the entire room, add all wall length measurements to get the circumference.

Find the total square feet of the wall(s) by multiplying ceiling height by room circumference. Subtract areas that will not be covered. Standard doors are about 3 by 7 feet, or 21 square feet. Standard windows are about 3 by 5 feet, or 15 square feet.

These calculations give you the total number of square feet to be covered. With this information, you or your retailer can determine how many rolls to order.

Step 2:

Calculate Your Rollage-Use the online calculator

There is no simple method for calculating rollage needs that is always 100-percent accurate. A pattern repeat, room of unusual shape or size, greater-than-normal waster during hanging, or other special circumstances can throw off any estimate. In order to calculate accurately, you need to determine the length of the pattern repeat, if any.

Using the following chart, find the usable yield for the wallcovering selected. Then, divide the square footage figure you have previously calculated by the usable yield for the wallcovering selected, rounding up to the nearest whole number. This will give you the number of single rolls needed.

Usable Yield Chart

These figures work well for normal-sized walls. For unusually short (under 3 feet, such as over kitchen cabinets) or high (above 9 feet walls), they do not apply. Talk to your dealer for those special circumstances.

Estimating Example:

With the measurements, you have made, you find the room has a total of 340 square feet. Your selection has a 9-inch repeat, giving you a usable yield of 22 square feet. Dividing 340 by 22 gives you 15.45, which you round up to 16 single rolls.

Keep in mind that wallcovering is sold in double-roll bolts. So, if you need 15 single rolls, you should order 16 single rolls, which is actually eight double-roll bolts.

Note that with wallcoverings, it's always better to have a little too much than not enough. Even the most experienced do-it-yourselfer can make an occasional hanging mistake that may necessitate using more wallcovering than originally planned.

Copyright © 1995 Paint & Decorating Retailer is published by the Paint and Decorating Retailers Association 403 Axminister Drive St. Louis, MO 63026-2941