The complexity of double winders
Double winder staircases are a challenge for even the most experienced carpet fitters. They require a 180-degree turn made entirely of narrow, pie-shaped treads. Because the tread width changes drastically from the inside pivot to the outer edge, the runner has to be pleated or box-cut at the narrow end on almost every single step to sit flat. It's a high-precision task that simply cannot be rushed.
Measuring for success
Measure each winder tread individually at the walk line, not at the inside corner. If you calculate based on the inside corner, you will be vastly short of material. Templating the winder section is mandatory for any double-winder project. You need to see how that runner flows through the 180-degree turn.
How much runner do I need?
Because of the sheer amount of cutting and pleating involved, waste is high. Always budget at least 20-25% waste for a double winder section. For a standard 13-step flight with double winders, 30 ft (9.1 m) is a safe order. The stair runner calculator will help you account for this specific winder configuration, but be generous with your order.
| Measurement | Imperial (in) | Metric (cm) |
|---|---|---|
| Straight step total | 150 in | 381 cm |
| Double winder total | 120 in | 305 cm |
| Waste allowance (25%) | 60 in | 152 cm |
| Total runner | 330 in (27.5 ft) | 838 cm (8.4 m) |
Know your numbers in 30 seconds
Enter your step count, tread depth and riser height — the stair runner calculator gives you the exact length to order, in metres and feet, with waste included.
Open the stair runner calculatorA double winder project is a true masterclass in stair runner installation. If you are buying your stair runner, ensure you choose a quality product that can be cut and pleated cleanly. You can find many stair runners for challenging stairs, and you should use the stair runner calculator to ensure you don't run short.
- Template the winders carefully.
- Expect to pleat or dart the runner on the inside edge.
- Use the walk-line measurement for each tread.
- Start with extra runner—double-winder waste is significant.
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.
Frequently asked questions
Why are double winders difficult?
The complex geometry of pie-shaped treads requires precise cutting and pleating of the runner to keep it flat.
How do I measure double winders?
Measure the going along the walk line (about two-thirds from the narrow edge) for each individual winder.
Is a double winder runner a DIY project?
It's a high-level project. Unless you have significant experience, it’s best left to a professional.
Do I need pleats?
Almost certainly. Pleats or darts are necessary on the inside of the turn to make the fabric lie flat on the tapering tread.
How much extra runner should I allow?
Expect 20-25% waste to account for all the individual pleats and the complexity of the turn.
Can I use patterns on double winders?
Patterns are extremely difficult to match here and are usually avoided by professionals.
Do the winders need a template?
Yes, it is highly recommended to get a clean result on any double-winder staircase.
What's the best runner for double winders?
A flexible, high-quality runner that is easy to shape and pleat without cracking.
Know your numbers in 30 seconds
Enter your step count, tread depth and riser height — the stair runner calculator gives you the exact length to order, in metres and feet, with waste included.
Calculate your double-winder runnerEvery guide is written from hands-on measuring and fitting experience, checked against the calculator’s own maths, and re-reviewed whenever prices or methods change. Read our editorial standards.