How to Measure Stairs for Carpet: A Step-by-Step Guide
To measure stairs for carpet, measure one step from the back of the tread, over the nosing, and down the riser, then multiply by the number of steps and add the landing. Here is the full step-by-step method, including winders and the mistakes that catch people out.
The Quick Answer
To measure a straight staircase for carpet: measure the depth of one tread (the flat part you stand on) from the back of the step to the front edge, wrap your tape over the nosing, and continue down the riser (the vertical face) to the bottom. That single tread-plus-riser figure, multiplied by the number of steps, gives you the length of carpet you need. For the width, measure the widest step from edge to edge. Most UK staircases have 12 or 13 steps, treads around 25cm deep, and risers around 20cm high — but never assume; older Liverpool terraces in particular vary step by step. Add 10% for trimming and pattern matching, measure the landing separately as a small room, and you have your figure. The rest of this guide walks through each stage in detail, including winder stairs, which need a different approach.
What You Need Before You Start
You need four things: a metal tape measure (fabric tapes stretch and lie), a notepad or phone to record each measurement, a helper if the staircase is wide or awkward, and a simple sketch of the staircase drawn before you start. The sketch matters more than people expect. Mark every step on it, note which steps are full rectangles and which are winders (the wedge-shaped steps that turn a corner), and mark where the landing starts. As you measure, write each figure directly onto the sketch next to the step it belongs to. This prevents the single most common DIY measuring failure: a list of numbers with no record of which step each one came from. Measure in centimetres rather than feet and inches — carpet is sold in metric widths, and mixing units is how ordering errors happen.
Measuring a Straight Flight, Step by Step
First, measure one tread from the back of the step (where it meets the riser above) to the front edge of the nosing. Second, wrap the tape over the nosing and measure down the riser to where it meets the tread below. Add these together — a typical UK step totals around 45 to 50cm of carpet. Third, count your steps. Fourth, multiply the tread-plus-riser figure by the number of steps. Fifth, measure the width of the widest step, including any exposed side if your staircase has open edges. If every step measured the same you could stop there, but in practice you should measure at least three different steps — the bottom step is often deeper, and settlement in older houses makes steps drift from one another. Always use the largest measurements you find. Carpet that is slightly generous can be trimmed; carpet that is short cannot be stretched.
Winders, Corner Stairs, and Landings
Winder stairs — the wedge-shaped steps that turn a corner — are where DIY measuring usually goes wrong. Each winder must be measured individually at its widest and deepest points, and each one is effectively cut from a rectangle of carpet the size of those maximum dimensions. That means winders waste carpet by design, and three winders can need as much material as five straight steps. Treat each winder as its own rectangle on your sketch and resist the urge to average them. For landings, measure the longest and widest points of the space as if it were a small room, and remember the carpet usually needs to wrap over the top step nosing — add one extra tread-plus-riser to the landing length to cover it. If your staircase has a half-landing mid-flight, measure the two flights separately and the half-landing as its own rectangle.
How Much Carpet for a Typical 13-Step Staircase?
The most common UK staircase configuration is 13 steps in a straight flight. Using typical step dimensions — around 48cm of carpet per step and an 80cm usable width — a straight 13-step flight needs roughly 6.5 metres of carpet length at stair width, before the landing. Cut from standard 4-metre-wide carpet, a straight flight plus a small landing typically comes out of a piece around 2.5 to 3 metres long, depending on how the cuts are planned. This is exactly why professional fitters plan the cutting layout before ordering: a clever cutting plan can take a staircase and landing out of surprisingly little carpet, while a poor one wastes metres. If your staircase has winders, add one full rectangle per winder at its maximum dimensions. When in doubt, round up — offcuts are useful for repairs, but a shortfall means a second delivery and a visible join.
Five Mistakes That Catch People Out
One: measuring only one step and assuming the rest match. In older Liverpool homes especially, steps vary, and the bottom step is frequently deeper than the rest. Two: forgetting the nosing. The tape must wrap over the rounded front edge of each tread — measuring tread and riser as flat faces undercounts every single step. Three: ignoring pattern repeat. Striped and patterned carpets need extra length so the pattern aligns up the flight; plain twist piles do not. Four: forgetting the landing wrap, where the landing carpet folds over the top step. Five: buying exactly the calculated amount with no margin. Professionals add roughly 10% for trimming, joins, and the inevitable surprise. A final tip: if your stairs are being fitted with a runner rather than full-width carpet, the measuring rules change — see our stair runner service page for how runners are sized.
Or Skip All of This — Free Measuring in Liverpool
Measuring stairs properly is one of the trickier DIY measuring jobs, and mistakes are expensive in both carpet and patience. If you are in Liverpool or anywhere across Merseyside, Princess Flooring will measure your staircase for free — no obligation, no call-out charge. One of our team visits your home, measures every step, winder, and landing properly, plans the most efficient cutting layout, and gives you a written all-inclusive quote covering carpet, underlay, gripper rods, and fitting on the same visit. We have fitted stair carpets across Toxteth, Aigburth, Wavertree, Allerton, and the wider city for over 16 years. Call 0151 709 4943 or visit our Lodge Lane showroom to book your free measure — and bring your sketch if you have one, we love a good staircase drawing.
Explore Our Flooring Services
Everything below is supplied and professionally fitted by our Lodge Lane team, with free home measuring across Liverpool and Merseyside.
Need Help Choosing Your Flooring?
Visit our showroom on Lodge Lane or call for a free, no-obligation quote.
Call 0151 709 4943