What is a slip test?
A slip test measures the coefficient of friction—basically, how much grip a surface provides—under standardised, controlled conditions. These tests tell us how well a material will perform underfoot, even when things are slightly less than ideal, such as with a stray bit of dust or a slightly damp sock. The higher the rating, the more grip the surface provides.
While these tests are more common for commercial projects, they are becoming increasingly relevant for residential stair runner selection. As a fitter, I always appreciate when a manufacturer provides this information; it's a mark of a quality, safety-conscious product.
How much runner do I need?
For a 13-step flight: 10 in tread run + 7.5 in riser + 0.75 in nosing wrap = 18.25 in per step. Total = 237.25 in (5.97 m). Plus 24 in finishing allowance = 261.25 in (6.57 m). With an 8% waste margin, you need approximately 23.5 ft (7.1 m).
| Measurement | US (in/ft) | UK (cm/m) |
|---|---|---|
| Tread run | 10 in | 25 cm |
| Riser height | 7.5 in | 19 cm |
| Nosing wrap | 0.75 in | 1.9 cm |
| Total per step | 18.25 in | 45.9 cm |
| 13-step subtotal | 19.77 ft | 5.97 m |
| Finishing allowance | 21.77 ft | 6.57 m |
| With 8% waste | 23.5 ft | 7.1 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 calculatorThe takeaway for your home
When you are choosing your runner, ask about its slip resistance. Look for products that are described as 'high traction' or 'slip-resistant'. While it's just one piece of the puzzle, combined with professional installation and the right underlay, it contributes to a safer, more confident home.
- Ask your retailer for slip resistance ratings.
- Prioritise products with a proven, reliable grip.
- Remember that installation—not just material—is key to preventing slips.
- Use a quality, stable underlay to ensure the runner stays grippy.
- Keep your runner clean and free of dust and debris, which can reduce grip.
Beyond the test
Testing is one thing; day-to-day use is another. A slip-resistant runner will only stay that way if it's well-maintained, properly installed, and kept clear of potential slip-inducing objects. Safety is a holistic approach, not just a rating on a specification sheet.
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.
Frequently asked questions
What is a slip test for carpets?
It is a standardised test that measures the carpet's coefficient of friction—how much grip it provides—when you step on it.
Are slip tests mandatory for home runners?
Usually not, but it is a good idea to choose a carpet that has been tested and has a good rating, as it is a mark of quality and safety.
What should I look for in a rating?
Ask for products with a high, proven slip-resistant rating. Your retailer will be able to help you interpret the numbers.
Can I improve my runner's slip resistance?
Only by ensuring it is properly installed and clean. You cannot realistically increase the intrinsic grip of the material itself once it's on the stairs.
Does the underlay affect slip resistance?
Yes, it matters. If the underlay isn't stable, the runner will slip. Use a high-quality, non-slip underlay that is correctly fitted.
Are some fibres more slip-resistant than others?
Generally, denser, more tightly woven fibres provide better grip than loose, shaggy fibres. Synthetic fibres that are inherently slip-resistant are also good options.
How does wear affect slip resistance?
As a carpet wears, it can lose its texture, which can reduce its slip resistance. Regular inspection and replacement as needed are important.
Should I prioritise slip resistance over style?
You should aim for both. Many of the most popular, high-quality runner materials are also excellent in terms of slip resistance.
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.
Plan your runner with the stair runner calculatorEvery 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.