For a standard 13-step staircase, you will need approximately 21 to 23 feet of a stair runner (about 60 to 70 square feet of total carpet). The exact amount depends on your step measurements, but costs typically range from $400 to $650 completely installed.
As you look at how to calculate carpet for stairs, you should; Add 5cm (0.05m) to the width. Add 5cm (0.05m) to the length per step – for example, 65cm for 13 steps. Leave a 10% increase for wastage and peace of mind.
For 12 standard stairs, you generally need a carpet runner that is 20 feet long, or about 9 to 12 square yards (80 to 108 square feet) if you are carpeting the full width of the stairs.
The "27-inch rule for stairs" typically refers to two important safety and comfort design guidelines.
Building construction code has very specific requirements regarding the height of steps. This is to minimize the number of trips and falls. And the vertical distance between floors is fairly standard, given usual ceiling heights and joists supporting the upper floor. The result usually falls between 13 and 15.
For 7 steps (which usually means 7 risers/treads), you will need a piece of lumber that is at least 8 to 10 feet long. The exact uncut length depends on your total rise (height), but a standard rule of thumb is to allow about 14 inches of stringer board per step, plus some extra length to account for the angles.
Finally, multiply the total number of straight steps by the m² needed for a single step to get the total amount of underlay required for your straight steps. In the example above, 13 steps x 0.36m² per step = 4.68m² total area.
For a standard straight staircase with 12 stairs, you will need approximately 20 feet of linear carpet length. If you are buying broadloom carpet to cover the entire width of the stairs (wall-to-wall), you will typically need about 7 to 9 square yards (around 60 to 80 square feet).
Not at all. In fact, carpet is making a major comeback in 2026. While hard surfaces like hardwood and LVP remain popular in open-concept spaces, interior designers are heavily utilizing carpet to add warmth, acoustic dampening, and custom textures to homes.
For the average straight staircase of 12 steps, which is 6 metres long, a stair runner costs between £50 and £200, depending on carpet quality.
Home Depot charges starting at $0.49 per square foot for basic carpet installation, though they frequently run promotional deals. Total project costs typically break down as follows:
The best carpet for stairs is nylon or wool in a low-pile or tightly-loomed construction. These materials withstand heavy foot traffic, bounce back from pressure, and resist matting on the edges.
The 7-11 stair rule is a widely used architectural and carpentry guideline stating that the ideal stair riser (the vertical height) should be 7 inches and the tread (the horizontal depth) should be 11 inches. This ratio mimics the natural human stride, providing maximum comfort and safety.
Stair carpet trends are heavily focused on making the staircase a focal point through bold patterns, natural textures, and creative runner installations. Rather than wall-to-wall carpeting, modern designs lean toward tailored, custom-width runners that leave painted or stained wood edges exposed.
For a standard staircase with 13 steps, you need approximately 22 feet of carpet (or 7.5 to 8 linear yards) for a runner. This translates to 65 to 75 square feet, depending on your exact stair width and design.
For 12 standard stairs, you generally need a carpet runner that is 20 feet long, or about 9 to 12 square yards (80 to 108 square feet) if you are carpeting the full width of the stairs.
The "25-inch rule" for stairs is a building and design principle stating that twice the riser height plus the tread depth should equal about 25 inches. It ensures stairs are comfortable and natural to climb, matching the average human stride.
Calculating carpet for stairs is easy once you measure a single step. For standard straight stairs, you only need to measure the depth of the tread (the part you step on), the height of the riser (the vertical part), and the width of the step.
High-traffic areas wear out faster
Here's a rough guide: Bedrooms: 10-15 years with light use. Living rooms and hallways: 5-10 years due to constant foot traffic. Stairs: The most wear-prone area, often needing replacement every 5-7 years.
A 14-step stair stringer (which creates 15 total risers) has a total installed height of about 94 to 112 inches (7.8 to 9.3 feet), depending on your local building code and step height.
Common stair design mistakes compromise both safety and structural integrity. The most critical errors include inconsistent step heights, treads that are too shallow, and inadequate headroom. Failing to meet local building codes, poor handrail placement, and using slippery materials also pose major hazards.
The "27 rule" usually refers to one of two staircase design and safety guidelines: