How to Measure Stairs for Carpet: Step-by-Step Instructions

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Quickly determine how much carpet your stairs will need
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Figuring the carpet for a staircase isn’t quite as straightforward as calculating how much carpet you’ll need for a room. To determine how much carpet you’ll need for your stairs, you have to account for the stairs, any overhangs, the pile of the carpet (which way the fibers lay flat), and any seams. But don’t worry—we’re here to walk you through every step!

How do you figure carpet for stairs?

  1. Stair Area = Stair Width × Depth (Tread Depth + Riser Height) × Number of Steps
  2. Landing Area = Landing Width × Landing Length
  3. Winder Area = Longest Width × Longest Length
  4. Total Carpet Needed = Stair Area + Landing Area + Winder Area
Section 1 of 5:

How to Measure Carpet for Stairs

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  1. The tread of a stair is the horizontal part of the stair on which you step. With a tape measure , measure from one side of the stair tread to the other side. Then, add about 2 in (5.1 cm) to account for any uneven spaces or mistakes. [1]
    • Standard treads are usually about 3 ft (0.91 m) wide. So, if the stair width is exactly 36 in (91 cm), with the added inches, the stair width would be 38 in (97 cm).
    • If your stairs have a railing on one or both sides, account for the extra carpeting needed to fit through the railing and around to the bottom of each stair—usually an extra 2 in (5.1 cm) per side.
    • If you plan to only install a carpet runner down the center of your stairway, measure the width of the area that you plan to cover. [2]
  2. Set your tape measure at the back edge of the tread and measure the tread from front to back. Then bend the tape measure down at a 90° angle and continue measuring in the same direction down the riser, or the vertical board that elevates the stairs. Add an extra 2 in (5.1 cm) to this measurement as well, and write this measurement down. [3]
    • The average tread depth is about 10–11 in (25–28 cm) and the average riser height is about 6 in (15 cm). If your tread and riser measured 16 in (41 cm), you’d write down 18 in (46 cm).
    • It’s a good idea to measure more than one stair, and even different points of the same stair, to make sure they’re all the same size.
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  3. If the tread has an overhang that goes beyond the riser (known as a nosing), measure back to the riser itself under the overhang and then down to the bottom. You’ll use the total measurement to calculate the height of each stair. Alternately, you can add about 2 in (5.1 cm) to the depth measurement to account for this overhang.
    • In the case of our example, this would make our length measurement 20 in (51 cm).
  4. Measuring the carpet for landings is straightforward: just write down the length and width of the landing. While you’re measuring the width of the landing, bend the tape measure and measure the height of the riser directly beneath it. A common landing size would measure something like 4 ft × 5 ft (1.2 m × 1.5 m). [4]
  5. If your staircase has winders—irregular-shaped steps that go around a curve or corner—measure those separately. Find where the step is the widest and deepest and take those measurements, then write them down. [5]
    • If you have a bullnose stair—a larger stair with curved edges at the bottom of your staircase—measure the width across the widest point.
    • If your stairs flare out so they’re wider at the bottom, measure each stair from the bottom individually until you’re sure the remaining stairs have the same dimensions.
    • There will be some excess carpet left over from winders or bullnoses, but that’s okay—it’s better than not having enough.
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Section 2 of 5:

Calculating the Area of the Carpet

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  1. Multiplying the rounded length and width measurements will yield the square footage of a step. The square footage—also called the area—of a step will give you the number of square feet (or meters) that you’ll need to cover with carpet. [6]
    • The area of the stairs in our example above would be 38 in (97 cm) times 20 in (51 cm). That works out to 760 sq in (4,900 cm 2 ), or 5.28 sq ft (0.491 m 2 ).
  2. Residential remodeling expert Josh Goldenberg says, “To calculate how much carpet you’ll need for stairs, multiply the number of stairs you have by the width and height of each individual stair.” If you measured by inches, he says to “divide that answer by 12 to get feet. This is how much square footage you’ll need for the stairs portion.”
    • If there are 8 steps on our staircase, that would be 6,080 sq in (39,200 cm 2 ) or 42.22 sq ft (3.922 m 2 ).
  3. Find the landing measurements that you calculated earlier. Multiply the landing’s length times its width. This will give you the total area of the landing (and the riser just below it). Add this number to the total area of the stairs to calculate the total surface you’ll need to purchase carpet for. [7]
    • In our example, the landing measures 4 ft × 5 ft (1.2 m × 1.5 m). Multiply these dimensions to calculate the amount of carpet you’ll need to cover the landing: 20 sq ft (1.9 m 2 ).
    • If you add that to the carpet needed for the stairs, you’ll need a total of 62.22 sq ft (5.780 m 2 ) of carpet for your staircase and landing.
  4. An online calculator can run the math equations for you, which may prove useful if you’re not confident in your math skills. Simply input the width and height of the number of stairs you’ll be carpeting. Hit the “calculate” key, and the calculator will give you the total area measurement.
  5. Mistakes can happen while carpet is being installed, and it’s always better to have too much carpeting than too little. So, when you’re ordering, add in an extra 10% of the total to make sure that you’ll have enough carpeting to compensate for any errors or uneven measurements. [8]
    • In our example, the total stair surface area came to 62.22 sq ft (5.780 m 2 ). Adding an extra 10% to this estimate gives us a final figure of: 68.44 sq ft (6.358 m 2 ).
    • Getting this measurement can be helpful when you’re trying to determine a budget for your carpeting—it will give you a general idea of how much carpet you’ll need. But because the nap of the carpet and the seams have to be calculated carefully for stairs, this won’t tell you exactly how much carpet to buy—you’ll need to use the next section for that.
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Section 3 of 5:

Determining How Much Carpet to Buy

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  1. A standard roll of carpet is sold in 12 ft (3.7 m) widths. Divide that by the width of your stairs to determine how many stair widths you can get from a single strip of carpet. Be sure to use your rounded-up measurement. [9]
    • In our example above, the carpet for the stairs was 38 in (97 cm) wide. When we divide that into 12 ft (3.7 m), we get 3.78—so you’ll get 3 stair widths out of every strip of carpet.
    • It’s okay if there’s a little left over. It’s more important that the seams and pile line up correctly than it is to use every inch of carpet.
    • The width of the carpet roll should always be calculated along the width of the carpet roll. This will ensure that the pile of the carpet goes the right way down the stairs—lifting up when you’re going up the stairs and laying flat when you’re coming down.
  2. The depth of the stairs is the number we got from measuring the height of the riser, the depth of the tread, any overhang, and a little extra as an allowance. This will tell you how far into the carpet roll you’ll need to go to cover a single stair. [10]
    • In our example, the depth was 20 in (51 cm). So based on our calculations, every 20 in (51 cm) by 12 ft (3.7 m) will cover 3 stairs.
  3. It’s usually easier to draw this out—sketch out a block of carpet, then draw blocks representing each of the stairs. Keep adding rows until you have enough blocks to cover all of the stairs. [11]
    • In our example, we can fit 3 stairs on each width of carpet and we need 8 total stairs, so we’d need 3 rows (3 on the first two rows and 2 on the third).
  4. Check your measurements sheet and add in anything that you need to carpet that isn’t already covered by the stair blocks. If you need to, you can rearrange the stair blocks to make the landings fit more efficiently. [12]
    • If we move one of our stair blocks up to a fourth row, we’ll be able to fit in the landing block and have a total carpet area of 144 in (370 cm) wide and 80 in (200 cm) long. This works out to about 80 sq ft (7.4 m 2 ). This is a bit more than our estimate above because the estimate didn't account for wasted carpet at the end of the roll.
    • This will give you more traction climbing up the stairs and make it easier to come down the stairs. It will also be easier to sweep dust and dirt toward the bottom of the stairs.
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Section 4 of 5:

Choosing the Right Carpet for Your Stairs

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  1. When you’re looking at carpets, consider factors like the material, pile, and twist. Look at how each of these fit into your budget, as well as which options are best for a busy staircase.
    • Material: Wool and nylon carpets tend to be more expensive and more durable than polyester. [13] But because they’re easier to clean, nylon and polyester may be more suited to high-traffic areas like a staircase.
    • Pile: Carpet with a longer pile will feel more plush but may cost more. But for safety reasons, a lower-pile carpet is usually recommended for stairs. [14]
    • Twist: Carpet with tightly-twisted fibers will cost more but will also last longer. A tighter twist may also be a better option for stairs.
Section 5 of 5:

FAQs

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  1. 1
    What direction should the pile go on stairs? The pile should face up when you’re going up the stairs. Position the carpet on the stairs so the carpet fibers feel smooth when you run you hand from the back of the tread to the front, and the carpet fibers lift up when you run your hand from the front of the tread to the back. [15]
    • The carpet pile refers to the direction the fibers lay.
  2. 2
    What’s the biggest mistake to avoid when measuring carpet for stairs? The biggest mistake you can make when you’re measuring for carpet is to just guess at the measurements. Double-check your measurements—measure the width and depth of multiple steps to make sure they’re all a consistent size. Also, be sure to include your landings and winders, and account for any doorways, bannisters, or alcoves. [16]
    • It’s a good idea to hire a professional to install the carpet on your stairs. If you’re having the work done professionally, they’ll be able to calculate the carpet you’ll need, minimize waste, and give you a cost estimate.
  3. 3
    How do you estimate the cost of carpet for stairs? Multiple the area of the carpet by the price per foot or yard to determine your cost. When you’re figuring your initial budget, you can use a rough estimate of the carpet’s area for a general idea of how much your carpet will cost. But when you’re getting ready to purchase, use more precise calculations to determine how much your carpet will cost.
    • The type of carpet will affect the price, as well as installation costs and where you shop.
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  • Question
    How do I convert square inches to square feet?
    Community Answer
    A square foot is the area of a square one foot (12 inches) on a side, so there are 144 square inches in a square foot. So divide the number of square inches by 144 to get square feet. Or if you're lazy, just type something like "5000 square inches in square feet" into a Google search, and Google won't just tell you the answer, it will bring up a conversion calculator!
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    How do I get 5 feet from 1887 inches?
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    You don't. 1887 sq inches should be divided by 144 sq inches (the amount of sq inches in a sq foot), and you should get 13.1 or so sq feet.
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    How do I round when putting carpet on stairs?
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    Round up, then just cut off the extra carpet.
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      References

      1. ↑ https://youtu.be/Zk9UfxlbUnk?t=52
      2. ↑ https://youtu.be/Zk9UfxlbUnk?t=97
      3. ↑ https://www.bobvila.com/articles/how-to-measure-stairs-for-carpet/
      4. ↑ https://youtu.be/Zk9UfxlbUnk?t=26
      5. ↑ https://www.homebuilding.co.uk/advice/how-to-measure-carpet-for-stairs
      6. ↑ https://sloanescarpetsecret.com/wp-content/uploads/2019/09/carpet-estimator-worksheet-1.pdf
      7. ↑ https://www.bobvila.com/articles/how-to-measure-stairs-for-carpet/
      8. ↑ https://sloanescarpetsecret.com/wp-content/uploads/2019/09/carpet-estimator-worksheet-1.pdf
      9. ↑ https://youtu.be/_6Ggx-oOcBc?t=120
      1. ↑ https://youtu.be/_6Ggx-oOcBc?t=123
      2. ↑ https://youtu.be/Nw3wYZPZum4?t=146
      3. ↑ https://youtu.be/_6Ggx-oOcBc?t=151
      4. ↑ https://www.flooringamerica.com/blog/understanding-carpet-costs
      5. ↑ https://diyhomecomfort.com/blog/how-to-measure-stair-carpet
      6. ↑ https://www.flooringtech.org/unit18_carpet_basics/section4_tufted_and_bonded_carpets/lesson2_setting_out_the_installation.htm
      7. ↑ https://www.bobvila.com/articles/how-to-measure-stairs-for-carpet/

      About This Article

      Article Summary X

      To calculate how much carpet you'll need for your stairs, start by measuring the width of 1 tread with a tape measure and add 2 inches to make sure you have enough carpet. Next, measure upward across the tread and riser of 1 stair. After measuring the riser, get the length and width of any landings, then round all of your measurements up to the nearest foot. Once you have these numbers, multiply the tread and riser measurements together to get the square footage of 1 step, then multiply your result by the number of steps. Likewise, multiply the length and width of the landing to get its area. Finally, add the area of the landing with the area of all the steps to find out how much carpet you need. For more tips, like how to know how much extra carpeting to get, read on!

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