Calculating the perfect tread
When you're measuring for your runner, remember that the tread depth often includes the nosing projection. If your stair runner is going to cover the entire tread, be sure to account for that nosing wrap. Fitting a runner on a shallow tread is much harder than on a deep one, so take extra care with your measurements if you have tight, steep stairs.
| Measurement Type | Recommended |
|---|---|
| Tread Depth | 220-280mm |
| Nosing Overlap | 16-25mm |
| Total Coverage | Sum of both |
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 calculatorWhatever 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 the ideal tread depth?
220mm-280mm is generally comfortable for most users.
Does tread depth include nosing?
Technically no, the going is the horizontal distance; the tread depth often includes the nosing.
How does depth affect carpet runners?
Deeper treads allow for easier fitting and better runner stability.
Can I adjust my tread depth?
Only if you're rebuilding the staircase; otherwise, work with what you have.
Are shallow treads safe?
Very shallow treads are a major safety hazard and should be avoided.
How do I measure for a runner?
Include the tread surface plus the nosing wrap to get the total length needed per step.
Is the calculator useful for renovation?
Yes, it helps you plan your runner coverage accurately.
Does code mandate tread depth?
Yes, local building codes always specify minimums.
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 stair renovation with our 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.