How carpet is measured for stairs and landings

Stairs are measured step by step: each step needs the depth of the tread, the wrap over the nosing and the height of the riser. As a rough guide, allow about 0.45 to 0.5 m of carpet per straight step. Winders, a bullnose bottom step and landings all add to this, so stairs are best measured on site before ordering.

Stairs are the part of a carpet job people most often get wrong when measuring themselves, because a staircase uses far more carpet than its footprint suggests, and the way carpet comes off the roll affects how it is cut.

Why do stairs use so much carpet?

On every step, carpet covers the flat tread, wraps over the nosing (the rounded front edge) and runs down the riser to the next tread. Across a full flight that adds up quickly. Measuring a staircase as if it were a small floor area gives a figure that is far too low.

Stair carpet also takes the most wear in the house, particularly on the nosings, which is worth bearing in mind when choosing the carpet itself. See wool vs polypropylene carpet for how fibre affects durability.

How do you measure a straight step?

For each straight step, measure:

1. Tread depth: from the back of the tread to the front of the nosing.
2. Nosing: a little extra to wrap round the front edge.
3. Riser height: from the top of the tread below to the underside of the nosing above.
4. Width: across the stairs at the widest point, wall to wall or wall to spindles.

Add tread, nosing and riser together for the length per step. A typical straight step in a UK house works out at roughly 0.45 to 0.5 m, which is where the common rule of thumb comes from. Multiply by the number of straight steps; a straight flight in a typical house often has somewhere around 12 to 14.

How are winders and bullnose steps measured?

• Winders are the triangular or wedge-shaped steps where a staircase turns. Each one is measured at its widest and longest points, because a rectangle of carpet has to be cut to cover it. They use noticeably more carpet than straight steps and generate more offcuts.
• Bullnose and curved steps, often at the bottom of the flight, wrap round a curve and need extra width and careful cutting.
• Open-sided stairs with exposed edges need extra so the carpet can be turned and finished neatly, or finished as a runner with the timber left visible at the sides.

How is a landing measured?

A landing is measured like a small room: the longest length by the widest width, in metres, including any area that runs into a cupboard or doorway. If you’re doing this yourself, the floor area calculator and the guide to measuring a room for flooring cover the method. Where the stairs and landing meet, the top nosing and riser are usually covered by the landing piece or a separate cut, which affects where the join falls.

How is stair carpet cut from the roll?

Carpet is usually made in wide rolls, commonly 4 m or 5 m. Most staircases are much narrower than that, so the stairs are often cut as several strips, each the width of the stairs, taken side by side from a length of roll. The strips are then joined where they won’t be seen, typically tucked into the angle where a tread meets the riser.

Pile direction matters too. Stair carpet is normally fitted with the pile running down the stairs, which helps with wear and appearance. That means every strip has to be cut the same way round, and it is one reason the quantity can’t simply be worked out from square metres. If you’re estimating waste generally, see how much extra flooring to allow for waste.

Which stair carpet fitting styles are there?

• Fitted carpet (wall to wall): covers the full width of each step.
• Waterfall: the carpet drops from the nosing straight to the next tread without following the riser closely. A similar quantity, but a different look.
• Hollywood: the carpet is pulled tight around the nosing and follows the riser. A neater, tailored finish that takes more time to fit.
• Runner: a narrower strip down the centre with the stair timber showing at the sides. This needs the stairs to be in good condition and finished, as the edges are on show.

Can I measure stairs myself for an estimate?

Yes, for a rough idea. Count the straight steps, measure one typical tread, nosing and riser, and note the stair width and the number of winders. Measure the landing separately. Add a photo of the staircase, and include all of this when you send your details for an estimate. The guide on what to send for a flooring estimate lists the useful details.

For ordering, though, a staircase really does need an on-site measure. Spindles, a turn, a half-landing or an open side all change the quantity, the cutting and where the joins go.

Common questions

How many square metres of carpet does a flight of stairs need?

It depends on the width, the number of steps and the roll width, which is why stairs aren’t usually quoted in simple square metres. For a straight flight, multiply the length per step by the number of steps, then work out how many stair-width strips fit across the roll.

Should the stairs and landing be the same carpet?

Usually, yes. They are normally fitted together and joined at the top of the stairs, so using the same carpet keeps the join less obvious. Doing both at once also avoids a colour mismatch between batches.

Do stairs need underlay?

Generally, yes. Underlay is cut to fit each tread, which cushions the carpet and helps it wear more evenly over the nosing.

Next step

For a full staircase and landing, request a home measure so the quantity, joins and pile direction are planned properly, or see our carpet page for the types that suit stairs.