Stair Carpet Calculator
Estimate stair carpet for your project with our free calculator. Get accurate material quantities, costs, and specifications.
Formula
Carpet per Step = Tread + Riser + (2 x Nose Tuck); Total = Per Step x Stairs x Width
For each step, add the tread depth, riser height, and nose tuck allowance at both top and bottom. Multiply this linear measurement by the number of stairs to get total length. Then multiply by the stair width to get square footage. Convert to square yards by dividing by 9.
Worked Examples
Example 1: Standard Residential Staircase
Problem: 13 stairs, 10-inch treads, 7.5-inch risers, 36 inches wide, with 1.5-inch nose tuck.
Solution: Per step = 10 + 7.5 + (1.5 x 2) = 20.5 inches = 1.71 ft\nTotal linear = 1.71 x 13 = 22.2 ft\nWidth = 36 / 12 = 3 ft\nSquare feet = 22.2 x 3 = 66.6 sq ft\nSquare yards = 66.6 / 9 = 7.4 sq yd
Result: 66.6 sq ft or 7.4 sq yd of carpet
Example 2: Wide Staircase with Landing
Problem: 15 stairs, 11-inch treads, 7-inch risers, 48 inches wide, 1.5-inch nose tuck, plus one landing.
Solution: Per step = 11 + 7 + 3 = 21 inches = 1.75 ft\nTotal linear = 1.75 x 15 = 26.25 ft\nWidth = 48 / 12 = 4 ft\nStairs sq ft = 26.25 x 4 = 105 sq ft\nLanding = 3 x 4 = 12 sq ft\nTotal = 117 sq ft = 13 sq yd
Result: 117 sq ft or 13 sq yd including landing
Frequently Asked Questions
How do I measure stairs for carpet?
Measure each stair by adding the tread depth (horizontal surface you step on), the riser height (vertical face), and nose tuck allowance (extra carpet tucked under the nose at top and bottom of each step, typically 1.5 inches each). Multiply this per-step measurement by the number of stairs, then multiply by the stair width. Always measure the widest and deepest stair if dimensions vary.
How much carpet do I need for 13 stairs?
For 13 standard stairs with 10-inch treads, 7.5-inch risers, and 1.5-inch nose tuck on a 36-inch wide staircase, you need approximately 28.2 linear feet of carpet. That translates to about 84.5 square feet or 9.4 square yards. Add 10 percent for waste and pattern matching, bringing your total order to about 10.3 square yards. Always confirm measurements on site as stair dimensions can vary.
What type of carpet is best for stairs?
Low-pile or loop carpet with dense fiber construction works best on stairs because it resists matting and wear from heavy foot traffic. Nylon and polyester are the most durable fiber choices for stairs. Avoid thick plush carpet on stairs as it can create a tripping hazard by making the tread feel less defined. A carpet pad of 3/8 inch or less with 8-pound density provides cushion without making steps feel unstable.
Should I waterfall or cap stair carpet?
Waterfall installation drapes carpet over the stair nose and down the riser in a smooth curve, which is easier to install and more budget-friendly. Cap installation wraps carpet tightly around the nose and staples it underneath, creating a tailored fitted look that shows the stair profile. Cap installation costs more in labor but provides a more professional appearance. Waterfall is better for DIY projects, while cap installation is preferred for high-end homes.
How do I calculate stair dimensions to meet building codes?
The standard rule is riser height plus tread depth should equal 17-18 inches. Most codes require risers between 4-7.75 inches, treads at least 10 inches deep, minimum 36-inch width, and handrails 34-38 inches high. Calculate number of risers by dividing total rise by desired riser height.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.