measuring and budgeting carpet

Measuring and Budgeting for Carpet

You could leave the carpet measuring up to the installers, but that could end up being a $1,000+ mistake. The measurement affects the price of everything: installation, carpet, padding, etc—yet most people don’t know how many square feet they need carpeted, let alone what this equals in amount of carpet they’ll be purchasing. This leaves the installer (or whoever measures your carpet) a dangerous amount of flexibility to manipulate the final price you pay.

Another reason you may want to consider measuring your carpet? It’ll help you create a budget, so you know how much you can spend on carpet per square foot.

The purpose of this article isn’t to make you a carpet installer—not even close. The purpose is to simplify carpet measurements (which can be pretty complicated), so you’ll be able to create a ballpark estimate, an estimate that will allow you to red flag scammy installers and/or create a budget before you shop.

By the way, there are companies like HomeAdvisor that will do the homework on installers for you, which gives you some peace of mind. Click here to enter a form with your zip code to get free quotes from pre-qualified installers in your area.

Captain says they’re not all bad guys. Most installers are good people who will give you a 100% fair measurement. Unfortunately, there are always some bad apples who can cost you a bundle. The point is don’t assume your installer is a bad person—give them the benefit of the doubt—but protect yourself at the same time.

Why Estimating Carpet the Right Way is Difficult

Accurately measuring carpet will give you a headache. It’s a two-step process that is much more difficult than you might initially assume. The first step is to measure you how much area needs carpeted (this is the easy part), and the second step is to determine how much carpet you will need to cover this area (this is wear it gets tricky).

The second part is tricky because carpet comes only in 12ft, 13-6ft, or 15ft rolls, and many times only in 12 foot rolls. This means, no matter how wide your room is, you have to order a 12 foot width of carpet (or 13-6 or 15 depending on what’s available). To complicate this further, you can’t just chop up the carpet and lay it any way. The installer has to take into account where seams will be, what way the carpet fibers lie, and what directions patterns are going. Each of these factors affects how much carpet is purchased.

This may be a little confusing, so here are two examples that demonstrate the problem I described above:

A small room size example (the roll size is the problem): Let’s say you are carpeting a bedroom that is 10 feet by 10 feet. You can do the math and determine that the area of this room is 100 square feet (10 *10 = 100). However, we discussed earlier that rolls come in widths of 12 feet, so the width can’t be any smaller than this. You’ll buy 10 feet (the length) of the 12 foot roll. This equals 120 square feet (10 * 12 = 120) or 20% more than the actual area of the room! This extra carpet is either stored to use as backup carpet (if you ever have a damaged spot you want to patch), or the installer can take it away.

A larger room example (seams and carpet patterns are the problem): Now let’s pretend you have another bedroom, but this one is bigger: 16 feet by 20 feet. Let’s say the carpet you choose only comes in 12 feet rolls (even if it came in 15 feet you’d still be short of the 16 foot width). This means that you can get 20 feet of the carpet, but an entire area 4-feet wide along the 20 foot wall won’t be carpeted (16 foot room width – 12 foot carpet roll width = 4 feet). The solution is to purchase more than 20 feet of length and use the extra length to fill in the gap. It may seem like you could do simple math to determine how much extra length to buy to fill in the 4 foot gap; unfortunately, it’s not that easy. Since you will want the carpet in as few cut pieces as possible, and the patterns and carpet to lay the same direction, the installer has to make a diagram to determine the correct amount to purchase—it’s more of an art than a science!

You’re probably thoroughly confused at this point, but don’t worry because it really doesn’t matter. The point of these examples is to show you why it’s impossible to predict exactly how much carpet you will need. The good news is you’re about to learn a method that is easy to follow, and will give you a ball park estimate that’s good enough to create a budget and keep your installer honest.

First things first: how to measure your rooms

This is the easy part. The only equipment needed is a tape measure, calculator, and pen and paper to write down your measurements. Then follow these simple steps:

  1. Start at one end of the room, and use the tape measure to measure to the other side of the room. Write this measurement down.
  2. Next, repeat this measuring the other distance of the room.
  3. Take your two measurements and multiply them. This is the square footage for that room.
  4. Repeat steps 1-3 for every room that is going to be carpeted.
  5. Add the square footage for each room together to get the total square footage.

Pretty easy, huh?

Captain’s making it simple. Most likely not all of your rooms are rectangles or squares, and this can make the measuring more difficult. Here’s a trick for odd shaped rooms: just measure from whatever area gives you the longest length. In other words, measure across the widest part of the room.

The 10% Rule

If you didn’t skip the top of the article, you have an appreciation for why estimating the carpet you’ll need is so difficult: seams, pattern matching, roll sizes, etc. The good news for you is you’re not an installer, and you don’t have to be exact. You can use the 10% rule: take whatever carpet total square footage measurement you came up with and multiple it by ‘1.10’. In example, if you determined that all of your rooms total 1,000 square feet, then you’ll estimate that you should purchase approximately 1,100 square feet. Just keep in mind that the true amount of carpet you need will vary from 2% to 20% more than what you measured—10% is just an average for estimation purposes.

What about stairs?

Stairs get complicated. There are many different sizes and different ways you can carpet them, so I’ll give you a secret to simplify things: don’t measure the stairs. Instead, you measure the rest of the house, but don’t let the store/installer know you did until they give their estimate. Then you check if the installers estimate seems reasonable compared to your estimate. If you feel like the installer cheated you, you’ll want to do business with another store. If you feel the installer was honest with their estimate compared to what you measured, chances are you can also trust their estimate on the stairs.

Captain’s parting words: See, estimating how much carpet you need isn’t so bad after all. The little work it takes pays off big time in creating a budget and also preventing being majorly overcharged. It’s important to keep in mind that your calculation is an estimate, so the official measurement likely will be a little more or a little less. If the installer’s estimate requires more carpet than yours, ask them politely to show you why there’s a difference. If what they say makes sense and the difference is reasonable, you know you’re being treated fairly. If you aren’t convinced they’re being honest with you, it’s in your best interest to do business with someone else.

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I have 500 sq (2bd with closets) that need carpet. Lowes came and measured and said I have 498 sq feet. I picked a square pattern carpet. The salesperson said I need 180 sq feet more because it is patterned carpet. Does that sound right?


We special ordered a 15ft carpet as our room is 13.6. We did not want any seams. There was not a lot to choose from but we found what we wanted. We were adamant on not wanting any seams. We came inside after letting the installer do his thing and he was putting a seam in. We told him we ordered 15ft so we would have no seams. He informed us it was a 12ft carpet. I immediately call Home Depot and spoke with the manager. Not only did we not have any seams, we now had 5. They had… Read more »

Douglas A Johannes

Good info! We have a finished basement, I recently removed a brick pedestal for a gas log heater. So my intention is to recarpet that room (16×23) with a remnant. I intend to use inexpensive indoor/outdoor carpet, I have received one estimate which I thought was high ($1,000+) so wanted to learn a bit more about this project before spending my hard earned $$$

I would likto know a ballpark figure on three fl

I would like to know a ballpark figure on three flights of stairs to an exterior three family home with 6 x 4 landings


Very informative, thank you. I just need to figure what type of carpet is best choice for stairway and hall, high traffic areas.. Anyone have recommendations for that?