The default: 10%
For a straight flight of uniform steps in a plain runner, 10% is the industry default and it is enough. On a 6m run that is 60cm — roughly the trimming, tucking and squaring losses a fitter incurs.
When to increase it
| Situation | Suggested margin |
|---|---|
| Straight flight, plain runner | 10% |
| Patterned runner | 10% plus one repeat per piece |
| Winders or a quarter turn | 15% |
| Curved or flared bottom steps | 15–20% |
| Old house, visibly uneven steps | 15% |
| First DIY attempt | 15% |
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 calculatorWhy not just add a metre?
A flat allowance under-protects long staircases and over-buys on short ones. A percentage scales with the risk, which is proportional to the number of cuts and steps.
Keep the offcut
Store any leftover with the dye lot number. A stair runner takes concentrated wear on the nosings; being able to patch or replace the bottom three steps in five years is worth more than the storage space.
What waste margin does not cover
- Pattern repeat — that is a separate, additive allowance.
- Measuring the wrong staircase geometry, such as forgetting the nosing wrap.
- Landings, which must be measured and added explicitly.
- Mistakes in unit conversion between inches and centimetres.
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
Is 10% waste enough for a stair runner?
For a straight flight in a plain runner, yes. Add more for winders, curves, uneven period stairs, or if you are fitting it yourself for the first time.
Does waste margin include the pattern repeat?
No. Treat them separately — waste is a percentage of the total run, pattern repeat is a fixed extra length per cut piece.
What do I do with the leftover runner?
Keep it flat and labelled with the dye lot. It is the only reliable way to patch worn nosings or replace a damaged step years later.
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.
Set my waste margin