Flooring guide

How to measure stairs for carpet

Reviewed October 6, 2026 · By the Room Calculators team · How we check facts

Stairs are measured step by step, not as floor area. Each step needs a piece that covers the tread (where you stand), wraps the nosing (the front edge), and runs down the riser (the vertical face).

Measure one step

1. Tread depth: from the back of the step to the front edge.
2. Riser height: from the top of one tread to the next tread down.
3. Nosing wrap: the extra length to curve around the front edge.
4. Width: the full width the carpet will cover.

Worked example

A straight staircase has 13 steps, each 10 in deep with a 7.5 in riser, a 2 in nosing wrap, and 36 in wide. Each step needs 19.5 in × 36 in, which is 4.9 sq ft. Thirteen steps is about 63 sq ft, or 7.0 sq yd, before any allowance for cutting and pile direction.

Landings, winders, and open sides

• Measure a landing like a small room: length × width.
• Winders (pie-shaped steps) need their widest dimensions; measure each one.
• Open-sided stairs may need extra to wrap the exposed edge.

Why stairs use more carpet

Carpet pile should usually run the same way on every step, and each piece is cut from a roll of fixed width. That leaves offcuts. Installers often lay out stairs from the roll differently from rooms, so share your measurements and let them confirm the order.