How Many Yards of Carpet Do I Need for Stairs?

The formula in one line

Length per step = tread depth + riser height + nosing allowance. Multiply by the number of steps, add landings, add waste, then divide by 36 for linear yards.

Quick chart by step count

Turning linear yards into square yards

If you are fully carpeting the stairs rather than laying a runner, the supplier will price by the square yard. Multiply the total run by the finished carpet width, then divide by 1,296 to get square yards.

Where the yardage quietly grows

• Wrapped nosings add roughly 1 to 1.5 inches per step.
• Patterned carpet needs a full pattern repeat added to every separate cut piece.
• Landings are measured as flat rectangles and added on top.
• Winders eat far more than a straight step — allow the widest point of the tread.
• Roll width dictates how many strips you can cut side by side; an awkward width wastes metres.

Worked example: a 14-step flight with a landing

Say you have 8 steps up to a half landing, then 6 more steps to the upper floor, with 10.5in treads and 7.5in risers. Each step consumes 18 inches, so 14 steps is 252 inches of run. The landing itself is a flat 36in x 42in rectangle, which at a 27in runner width needs another 42 inches cut lengthways along the direction of travel. Total run before waste is 294 inches. Add 10% waste and you land on roughly 323 inches, or 9 linear yards. Because the flight is now three separate pieces — lower flight, landing, upper flight — a plain carpet needs no further allowance, but a patterned one needs a repeat added at each of the two joins.

Full carpet vs a runner: yardage compared

Common yardage mistakes

• Measuring the tread depth flat instead of following the nosing profile, which quietly loses half an inch per step.
• Forgetting that a return nosing at the top or bottom step needs its own small allowance.
• Using a generic 'yards per stair' rule of thumb instead of measuring actual tread and riser sizes, which vary by 2 to 3 inches between houses.
• Ordering square yards when the supplier actually needs a linear length to cut from the roll.
• Not accounting for a half-width landing that still needs a full-width strip of carpet.

DIY measuring vs a fitter's survey

A homeowner with a tape measure and this calculator can get within 5% of the correct yardage on a straight flight — good enough to order with confidence. Where it pays to have a fitter survey in person is winders, curved bottom steps, or anywhere the treads visibly vary in depth from step to step, since a single mismeasured winder can throw the whole run out by half a yard.

Cost context for the yardage you calculate

Metric equivalents for UK buyers

UK suppliers rarely sell by the yard at all — carpet and runners are priced per linear metre. A linear yard is 0.914m, so the 7.2 yards needed for a 13-step US flight converts to roughly 6.6m. Always confirm which unit a quote is using before comparing two suppliers, especially when one is a UK mill and the other a US retailer.

How roll width affects your yardage order

Broadloom carpet typically comes in 12ft or 15ft rolls, and a runner is cut lengthways from that width, leaving offcuts either side. A fitter or supplier with a wider roll in stock can sometimes nest two runner widths side by side and cut your order more efficiently, which occasionally shows up as a lower quoted price per yard even for an identical finished product. It rarely changes the linear yardage you personally need, but it is worth asking about if two quotes for the same runner differ noticeably.

Ordering for multiple identical staircases

• If you are fitting the same runner to two staircases in one property, combine the orders into a single length rather than two separate calls — it is cut from one continuous roll and guarantees an identical dye lot.
• Add the waste margin once to the combined total rather than separately to each staircase; this typically saves half a yard or more on the second flight.
• Keep a single offcut large enough to patch either staircase, rather than two smaller offcuts that may each be too short to be useful.
• Tell the supplier upfront that the order covers two locations, since some will offer a small discount for a longer single cut.

A note on estimating tools

Any online calculator, including the one above, is only as accurate as the tread and riser measurements you enter. Measure at least three steps on the flight rather than assuming they are identical — older staircases in particular can vary by half an inch or more between the top and bottom of the run, and that variance compounds over a dozen or more steps into a meaningfully different total.

Whatever you decide, get the numbers first: the stair runner calculator doubles as a stair runner length calculator, adding nosing wrap, landings, winders, pattern repeat and waste so you order the right length the first time.

Still deciding on material, width or pattern? Our hub on stair runners compares weaves, widths, backings and fitting styles side by side, then hands the numbers straight to the calculator.