Advanced options
Each step needs tread + riser + 2cm to wrap the nosing. A straight flight is assumed: winders (kite-shaped turning steps) each need a full stair-width square of carpet, so add one width-x-width piece per winder. Measure the widest point and always let the fitter confirm before ordering.
What The Stair Carpet Calculator Works Out
- Carpet length needed: each step takes tread plus riser plus 2 cm to wrap the nosing, multiplied by the step count, plus a 40 cm fitting allowance. Thirteen steps at a typical 25 cm tread and 20 cm riser need about 6.5 linear metres.
- Area to buy: the length multiplied by the stair width plus 10% waste, roughly 6.4 m2 at a 90 cm width. Measure the widest point of the flight and let the fitter confirm before ordering.
- Carpet cost: the area at your price per m2. Stairs take the heaviest, most concentrated wear in the house, so the received wisdom is an 80/20 wool twist or hard-wearing loop rated for heavy domestic use, typically GBP 20 to GBP 45 per m2.
- Winders and landing (advanced): each kite-shaped turning step consumes a full stair-width square cut on the angle, and half-landings add their own rectangles, which is why L-shaped flights quote higher than their step count suggests. Winders are taken out of the straight-run length and added back as squares.
- Fitting allowance and waste (advanced): edit the 40 cm allowance and the 10% waste. Patterned or striped carpet that must match across steps can need 15% to 20%.
- Roll length to order (advanced): stair carpet is cut as strips from a 4 m or 5 m wide roll, so a 90 cm flight gets four strips from one length of 4 m roll. The figure shows how much roll length to ask for, and why a staircase is exactly the job remnant bins exist for.
- Underlay and grippers (advanced): a firm (not luxuriously thick) underlay over the same area at your price, typically GBP 4 to GBP 8 per m2, plus gripper rod at two widths per step. Squashy underlay on stairs makes carpet flex and wear at the nose.
- Fitting (advanced): fitters price stairs per step, commonly GBP 5 to GBP 10, with uplift and disposal of the old carpet extra. Knee-kicker tension and proper stretching onto grippers are what stop dangerous loose-carpet creep.
- Total project cost (advanced): carpet plus underlay, grippers and fitting, itemised in the table. The carpet itself is often the minor line; the extras commonly double the ticket.