How Much Wallpaper Do I Need? Free Calculator and a Simple Method

If you are about to wallpaper a room, the scariest part is ordering. Buy too little and you wait days for a matching batch, or worse, the store is out of your dye lot. Buy too much and you have thrown money away. The good news: getting the number right is simple once you know the method, and you can skip the math entirely with the free calculator below, which also estimates your full project cost (material plus installation).

The quick method

Wallpaper is sold by the roll, and rolls vary in size, so you cannot just eyeball it. Here is the reliable sequence:

1. 1Measure each wall: width and height in feet. Write them down.
2. 2Multiply width by height for each wall, then add them up. That is your total wall area.
3. 3Subtract the area of big openings (doors and large windows). Small windows you can usually ignore for a safety margin.
4. 4Check the roll you want: the label lists its coverage, usually in square feet, after a normal waste allowance.
5. 5Divide your wall area by the coverage per roll, then round up. Add one extra roll as a safety buffer.

The three things that make people over or under order

1. Pattern repeat

If your wallpaper has a design that repeats, every strip has to be lined up to match the one next to it. That alignment wastes a bit of paper at the top of each strip. A large pattern repeat can mean noticeably more rolls than the raw square footage suggests. Plain or textured paper with no repeat wastes almost nothing.

2. Waste factor

Trimming at the ceiling and baseboard, plus the odd mistake, means you never use 100 percent of a roll. A 10 percent waste allowance is normal for a simple room, and more for rooms with lots of corners, angles, or a big pattern repeat.

3. Doors and windows

Subtracting openings saves you money, but only subtract the big ones. If you cut your estimate for every small window and outlet, you leave yourself short. Take out doors and large picture windows, and leave the small stuff as buffer.

A quick example

Say you have a 12 by 14 foot bedroom with 9 foot ceilings, one door and one window:

• •The four walls come to roughly 468 square feet of surface.
• •Take out the door and window, call it about 430 square feet to cover.
• •A common roll covers around 56 square feet after waste, so 430 divided by 56 is about 8 rolls.
• •With a patterned paper, round up and add a buffer roll: order 9 to 10.

That is the math the free calculator does for you in about a minute, including the pattern repeat and waste that are easy to get wrong by hand.

Should you hire a professional to hang it?

For plain paper in a small, square room, a careful DIYer can do it. But patterned, large, or specialty wallpaper is genuinely hard to hang clean: the seams have to be invisible, the pattern has to march straight across corners, and bubbles are unforgiving. A professional installer also wastes less paper, which can pay for a chunk of their fee.

If you would rather have it done right, we match you with a licensed, insured installer in your area who is 5-star rated and guarantees their work - and you get 10 percent off for coming through WallFlow. Run your numbers in the calculator, leave your details, and we connect you. It is free and there is no obligation.

Common questions

How many rolls do I need per wall?

It depends on the wall size and the roll, but a single standard roll covers very roughly 55 to 60 square feet after waste. A typical accent wall takes 3 to 4 rolls. The calculator gives you the exact figure for your walls.

Can I return extra unopened rolls?

Many retailers accept unopened, uncut rolls within their return window, so buying one safety roll is low risk. Always keep your receipt and do not remove the wrapping until you are sure you need it.

Is the calculator really free?

Yes, completely free and no signup. If you want it installed, matching you with a local professional is free too.