How to Measure Stairs for Flooring — Carpet, LVP, and Hardwood

Count the number of steps

Count every step from bottom to top, including the landing at the top if it will receive the same material. Write down the total. A typical single-storey staircase has 13–15 steps; a basement stair has 12–14.

Tip: Don't forget to include the landing at the top of the stairs if it will be carpeted or finished the same as the stairs.

Measure the tread depth

The tread is the horizontal surface you walk on. Measure from the back of the step (where it meets the riser) to the front edge of the nosing (the overhang). A standard stair tread is 10–11 inches deep; some open-riser stairs have shallower treads. For carpet, you need to include the nosing wrap — add 2 inches to the tread measurement to account for carpet wrapping under the nosing.

Measure the riser height

The riser is the vertical face between steps. Measure from the top of one tread to the top of the next — a standard riser is 7–8 inches. For carpet installation, you need enough material to cover both the tread and the riser. For hard-surface installations (LVP or hardwood), the riser is typically painted or covered separately; the nosing piece caps the front edge.

Tip: If risers will be painted rather than carpeted, subtract the riser dimension from your carpet calculation.

Measure the stair width

Measure from wall to wall (or spindle base to wall if balusters are present) at the widest point of each step. Write this down — if all steps are the same width, one measurement suffices. For winder stairs, measure each winder step individually at its widest point.

Calculate carpet square footage

For wall-to-wall carpet on stairs: (Tread + Riser + 2" nosing wrap) converted to feet × stair width in feet = sf per step. Multiply by number of steps. Add 10% waste allowance. See the formula above for a worked example.

Calculate hard-surface nosing requirements

For LVP or hardwood stairs, the tread is often matched to the floor plank and a pre-finished nosing piece is used to cap the front edge. Count one nosing piece per step. Measure the width of each step — nosing pieces are typically sold in 94-inch lengths that can be cut to width. Calculate: (stair width in inches ÷ 94) rounded up = pieces needed per step. Multiply by steps and add 10% waste.

Tip: Nosing pieces must match the flooring product exactly — order them from the same manufacturer as the floor planks.

Factor in winder steps

Winder (pie-shaped) steps require significantly more material than straight steps because of the triangular shape's waste. For carpet, a winder step may use 150–200% of the material of a straight step. For hard-surface, winders often require custom-cut nosing. Tell your installer the exact number of winder steps — they will measure and plan the material layout.