How to Measure Stairs for Carpet

Adding carpet dramatically alters the look of a plain wooden staircase—and adds considerable comfort. But before you start looking at carpet swatches, it’s a good idea to measure your stairs to know exactly (or at least semi-precisely) how much carpet you’ll need to do the job.

Measuring carpet can be a tricky process. Carpeting on stairs is usually installed in separate pieces (rather than one large piece), and precision is required to achieve clean edges and trim and a polished final result.

The right approach to measuring stairs for carpet depends on the floor plan, the size of the staircase, the type of stairs involved, and if the homeowner wants a runner or fully carpeted stairs.

Below are the tools, materials, and step-by-step instructions you will need for the job.

Time required: One hour or less
Difficulty: Intermediate
Estimated cost: Less than $10

Before You Begin…

Measuring carpet for a staircase necessarily requires that you do some calculations. You’ll need to measure (in square feet) not only each individual stair, but also any stair landings or adjacent hallways that you would like to carpet. We advise double-checking all your measurements before placing a carpet order to make certain you don’t underbuy or over-spend. (Note that if you’re hiring a professional for the job, they will be able to measure the stairs for you.)

If you are replacing an existing carpet that was recently removed, the best moment to clear all nails, tack pads, glue, and other debris before you start measuring, not only to simplify installation later on but also to ensure highest possible degree of accuracy in measuring.

Tips for How to Measure Stairs for Carpet

• Carpet pieces are sold by the square foot or the square yard, and these are not interchangeable units of measurement! Be aware and remember to convert your measurements appropriately as needed.
• Some stairs may not be the same size as the others. It’s advised to measure each stair individually, even if the staircase is not irregularly shaped.
• Buy a bit of extra carpet in case of mistakes or if additional pieces are needed towards the project’s end.

STEP 1: Draw the floor plan of your stair landing, staircase, and any adjoining hallways.

It’s essential to start with a floor plan that lays out the entirety of the measurements needed for the staircase, including the landings and hallways. Using a piece of paper, pencil, and ruler, draw out the floor plan of these areas (using your best judgment on appropriate scale). Add any doorways and alcoves on the plan. Keep the floor plan handy when measuring.

STEP 2: Measure the stair landing.

The staircase carpet will flow from the landing to the rest of the stairs, making this starting measurement a crucial step. Stand on the staircase’s top step and measure the landing area’s width and length using a measuring tape. Note this measurement on the floor plan. Next, multiply the measurements to calculate the number of square feet needed for the landing. Remember to convert to square feet by dividing this number by 12.

STEP 3: Measure the rise and run of your stairs and add to the landing measurement.

The rise of a stair is the height, and the run of the stair is the depth. The width of the stair is the measurement from the edge to the wall. For a straight staircase, measure the rise and run in inches (with an extra inch or two for the nose) of one stair and multiply that number by the total number of stairs. Divide this number by 12 to get the measurement in feet. Measure the width of one stair to the nearest foot. Multiply this number by the rise and run feet measurement to obtain the area in square feet.

This measurement can also be used when painting a staircase. How to measure stairs for a carpet runner is similar to the above solution. Remove at least 4 inches from each side of the stair width in the above calculations.

STEP 5: Use your measurements to calculate the amount of carpet you will need for your staircase.

Using the floor plan and all its measurements, enter these values into an online carpet calculator tool to determine the amount of carpet needed for the staircase. Additionally, you can add the calculations from the landings, stairs, and hallway to determine the total carpet needed.

Remember to add about 10 percent of carpet to the final number to account for any carpet waste or mistakes in the carpet installation process. If you have a bullnose stair (a bottom stair that’s wider than the others and usually has a rounded edge), it will also be necessary to order a bit of extra carpet. It’s better to have too much carpet than not enough to finish the job.

STEP 6: Determine whether you will install the carpet yourself or hire a professional.

Once all the measurements have been calculated, it’s time to determine if the carpet will be a DIY project or if you’ll outsource the job to a professional.

If a staircase is irregular, winding, or has a complex layout (or if a homeowner doesn’t have the time or skills to complete the project), it’s always best to hire a professional. A professional will double-check measurements and order the exact amount of carpet needed so that the homeowner can avoid material waste or costly rework during the installation process.

Measuring stairs for carpet is a simple process once you get the hang of the basic calculations and measuring techniques. After you’ve calculated your final measurements for your staircase, you’ll be one step closer to the carpet installation process.