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  • Writer's pictureAron Pinto

Home Improvement 101 – The Right Way to Estimate How Much Carpet You Need Before You Shop

Whether you are upgrading the flooring in a new home, or staging your Waterloo Region home for sale, new flooring can make a huge difference to the overall look and feel of a room, just one of the reasons new flooring is high on the list of home improvements for many homeowners.

For many homeowners it has been a while since they have had to utilize any of the math they learned in school beyond balancing their checkbook at the end of the month and calculating the total of their weekly grocery trip.

So when it comes to figuring out the square footage of a room in order to go shopping for flooring it is hardly surprising that many of us have forgotten how to do that.

For example, imagine you are replacing, or adding, new carpet to your living room, bedroom, and hallway, but not in the bathroom. How can you calculate approximately how much you will need so that the carpet showroom salesperson can start talking prices? You could guess and wait for the installer to come out and do the final measurements after you have picked your carpet out. But by doing that you may cheat yourself out of the carpet you really wanted.

If you over calculate you may pass on that more expensive wool carpet you want because you believe it is too costly when in actual fact you only needed half the amount you thought. Or vice versa, an expensive carpet becomes even more so because you underestimated. So going out shopping with a good idea of the floor space that needs to be covered is always the best plan.

Now down to the maths part (yes you can use a calculator by the way) To determine how much carpet you’ll need, you’ll use this simple formula: A = L x W, or in other words, “area equals length times width.”(you see its coming back to you now, your seventh grade math teacher would be proud)

For our example start by figuring the total area of the floor plan. When you’re done, you can deduct the area of the bathroom, since you don’t want to carpet that room at the moment.


To figure out the total area of the floor plan, you’ll need to know the total length and width. The total length of the floor plan shown to the left is 12 feet plus 10 feet, or 22 feet. The total width is 7 feet plus 5 feet, or 12 feet. Plug these numbers into your equation to get the total area of the floor plan: A = 22 feet x 12 feet so A = 264 square feet.

Now deduct the bathroom area, which in this is example is 7 feet long and 5 feet wide which gives it a total square footage of 35 sq ft. This leaves you with a measurement 229 square feet.

You will need to add a waste factor which varies depend on room shape and carpet width. As a general rule the waste factor can be anywhere from 7% to 15% and your salesman can help you by looking at your drawing.

In this example assuming carpet is 12′ wide you will need 12′ x 22′.03″ or 267 sq feet of carpet and a solid number to take carpet shopping with you. This formula will work for many other types of flooring as well, so this one is a very handy one to hang on to. 

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