CarpetCalc Tip

Carpet for stairs calculator

Each step needs a piece as wide as the stairs and as long as the tread plus the riser plus a little extra to wrap the nose. CarpetCalc fits as many of those pieces side by side across the roll as it can, then counts the rows. This page starts with a typical straight staircase: 13 steps, 36 inches wide, with 10-inch treads and 7½-inch risers. Four 36-inch pieces fit across a 12 ft roll, so 13 steps take four rows, about 6½ linear feet.

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    Pile direction should run down the stairs on every step. Winders, open sides and landings need extra; measure landings as a small room and add them.

    How the carpet calculator works

    CarpetCalc works out both layouts. Strips running along one side are that side plus the trimming allowance long; the number of strips is the other side ÷ the roll width, rounded up. Linear feet = strips × strip length, carpet area = linear feet × roll width, and square yards = square feet ÷ 9. It keeps the layout with fewer linear feet (or fewer seams on a tie). Pad = floor area plus the extra you set; tack strip = perimeter − doorways. For stairs, each piece is tread + riser + wrap long, and as many pieces as fit side by side across the roll are cut from each row.

    Carpet bought from a 12 ft roll (6″ trimming allowance)

    RoomFloorCarpet boughtSeams
    10 × 12 ft13.33 sq yd14 sq yd (10.5 linear ft)0
    12 × 12 ft16 sq yd16.67 sq yd (12.5 linear ft)0
    12 × 15 ft20 sq yd20.67 sq yd (15.5 linear ft)0
    12 × 18 ft24 sq yd24.67 sq yd (18.5 linear ft)0
    14 × 16 ft24.89 sq yd38.67 sq yd (29 linear ft)1
    16 × 20 ft35.56 sq yd44 sq yd (33 linear ft)1

    Real layouts also depend on pile direction, pattern repeat, seam placement and how offcuts can fill closets and doorways, so a store or installer may plan the cuts differently. Patterned carpet needs extra for matching the repeat. Results are estimates: have the room measured before you order.

    Frequently asked questions

    How much carpet do I need for 13 stairs?

    For 36-inch-wide stairs with 10-inch treads and 7½-inch risers, about 6½ linear feet of a 12 ft roll, roughly 8.7 sq yd.

    How do you measure stairs for carpet?

    Measure the width, the tread depth including the nose and the riser height, and add about 2 inches per step to wrap the nose.

    Do I need pad on stairs?

    Yes, usually cut to cover the tread and wrap over the nose, but not the riser.

    Is CarpetCalc free?

    Yes, with no sign-up or ads.

    Are my measurements saved?

    Yes, in this browser only.

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