How Many Metres of Stair Runner Do I Need?

The short answer, then the working

Most homeowners asking this question have a straight staircase with somewhere between 12 and 16 steps, and for that range the honest answer is 'you will almost certainly need somewhere between 6.5 m and 9 m', but nobody wants to order carpet against a range that wide when it's sold by the metre and offcuts don't get refunded. The only way to get a number you can actually hand to a supplier is to measure the going (the horizontal depth of each tread), the rise (the vertical height of each riser), count your steps, then add a wrap allowance for the nosing at the front of each tread plus a waste margin for cutting. I've fitted enough stairs to know that a job that's short by even 15 cm at the top of a flight means a return trip and an awkward join, so it pays to over-measure slightly rather than order to the exact metre.

The other reason a single rule of thumb doesn't work is that not every staircase has a flat going and a flat rise. Older UK Victorian and Edwardian houses often have a deeper going than a modern new-build stair, and some houses have open-riser stairs where there's no riser section to wrap at all, just a tread. Both change the metreage meaningfully, so treat any online chart giving you 'metres per step' as a rough starting point only.

How much runner do I need?

Take a US example first: a straight 13-step flight, 10 in tread going and 7.5 in riser height, with a 0.75 in nosing wrap allowance on each step for a standard rounded bullnose. Per step that's 10 + 7.5 + 0.75 = 18.25 in. Across 13 steps that's 237.25 in, which is 19.77 ft. Add a top-and-bottom finishing allowance, commonly 12 in at each end to tuck under landing carpet or finish cleanly at the base, and you're at 261.25 in, or 21.77 ft. Apply a 7% waste margin for straight cuts and joins and the order length comes to roughly 23.3 ft, which most fitters round up to 23-24 ft to leave a safety margin.

The metric version of the same flight: 25 cm going, 19 cm riser, 1.9 cm nosing wrap, giving 45.9 cm per step. Multiply by 13 steps for 596.7 cm, add a 60 cm total finishing allowance (30 cm at each end) for 656.7 cm, then apply the same 7% waste margin to land at approximately 7.03 m. So a 13-step flight measured either way comes out to the same physical length, roughly 7 m or 23 ft, which is a useful sanity check when you're converting between the two unit systems for a supplier quote.

Why the waste allowance matters more than people think

A 5-10% waste margin isn't padding for the supplier's benefit, it covers real cutting losses: pattern matching on a striped or bordered runner, trimming a slightly uneven starting edge, and having enough spare to re-cut a bottom step if your riser heights turn out to vary by a centimetre or two, which they very often do on older houses where the treads were never perfectly level to begin with. On a patterned runner with a large repeat, I'd push the waste allowance to nearer 10%, since matching the pattern across a winder or a landing join eats into the roll faster than a plain weave does. On a plain flat-weave runner in a single colour, 5-7% is usually enough.

• Measure every tread and riser individually rather than assuming they're all identical - older stairs rarely are.
• Round your final length up to the nearest 0.5 m or 1 ft, not down.
• Add extra for any winders, half landings or full landings the runner crosses.
• Ask your supplier whether the roll width covers your chosen runner width without an extra seam.
• Keep any leftover offcut in case a future repair or re-stretch needs a patch that matches the dye lot.

What changes the metreage beyond a straight flight

Winders (the pie-shaped steps used to turn a corner) need more runner per step than a straight tread because the going varies across the width of the step, and a half landing or full landing adds a flat section that's priced and cut differently to the stepped sections. If your staircase has any of these features, treat the straight-flight calculation above as only part of the total, and measure the winders and landing separately before adding them together. Stair runners bought for a flight with a turn in it are one of the most common places people under-order, because it's easy to measure the straight run carefully and then guess at the turn.

Runner width is the other variable that affects how much you buy, since some suppliers sell stair runners by length only once you've picked a fixed width, while others cut bespoke widths from a broader roll and charge by the square metre or square foot instead. If you're buying by area rather than running length, multiply your calculated length by your chosen width to get the total area, and check whether the supplier's minimum order length is longer than what you actually need, which happens more often than you'd expect with narrower specialist widths.

Getting this right before you place an order is exactly what the stair runner calculator is built for: plug in your step count, going, rise and chosen waste percentage, and it converts your specific staircase into a metreage or footage figure in both units, rather than leaving you to do the arithmetic by hand or guess from a generic chart.

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.