Calculate how much stair runner to order for one straight run. Include the covered treads and risers, measured profile allowance, straight landing length, finishing, pattern allowance and the supplier's sale increment.
Stair runner length calculator
Free planning toolHow much stair runner do I need?
You need the length that follows the surfaces the runner will cover, plus the allowances required for your chosen finish and design. Then round that length up to the supplier's sale increment. A floor-area calculation alone does not tell you how long a continuous runner must be.
This stair runner calculator offers two routes. Enter a complete measured path, or build an estimate from covered tread lengths, covered riser lengths and additional profile length. Both routes then use the same allowances and ordering calculation.
Measure the path, including the last riser
Mark the intended start and finish before taking measurements. Use a flexible tape along the route the installed runner will follow. Include a flat landing only where the same straight runner actually continues across it. If you already measured the complete route, do not add the noses or landing again.
Roger Oates' measuring guide tells readers to include the stair nose, check whether steps differ and measure the final riser. Its allowance guidance is specific to that product. Use the relevant supplier's instructions for your runner.
In the parts method, a tread is a covered horizontal surface and a riser is a covered vertical surface. Count them separately. For example, a run might cover 12 treads and 13 risers. Entering 12 for both would leave one riser out. Your staircase may have different start and finish points, so do not copy these counts without checking.
When using one tread depth and one riser height, check that the covered surfaces are consistent. If they vary, measure and add each section yourself, then enter the sum as the complete measured path. This avoids averaging away an important difference.
Stair runner length formula
For the parts method:
Covered path = tread count × covered tread depth + riser count × covered riser height + tread count × extra profile length per tread + straight landing or floor length.
For either method:
Required length = (covered path + total finishing allowance + total pattern allowance) × (1 + reserve percentage ÷ 100).
Order length = required length rounded up to a whole number of the supplier's sale increments.
The extra profile field only covers length that is not already included in the flat surface measurements. It is applied once per counted tread. It is not a universal nosing dimension. A complete path measurement is usually easier when the runner follows a shaped or wrapped profile.
Worked example: 12 treads and 13 risers
Suppose the covered treads are 28 cm deep and the covered risers are 18 cm high. The measured additional profile allowance is 2 cm per tread, and the runner continues across a 100 cm straight floor section. These are example inputs, not standard stair dimensions.
The covered path is 12 × 28 + 13 × 18 + 12 × 2 + 100 = 694 cm, or 6.94 m. Add a total of 50 cm for end finishing and 30 cm for the agreed pattern allowance. That gives 7.74 m. An additional chosen reserve of 5% adds 0.387 m, bringing the requirement to 8.127 m.
If the supplier sells in 0.1 m increments, round up to 8.2 m. The rounding adds 0.073 m, or 7.3 cm. At an entered example price of €45 per metre, the runner material cost is €369. The figures are illustrative and are not a product quotation or a recommended allowance.
With a finished runner width of 70 cm on a clear stair width of 90 cm, a centred runner leaves (90 − 70) ÷ 2 = 10 cm exposed on each side. The width diagram illustrates this geometry. It does not establish an installation clearance.
Waterfall and wrapped fitting
The intended fitting style affects the path you measure. Alternative Flooring explains waterfall and Hollywood fitting: waterfall passes over the tread edge and down, while the wrapped style follows the profile more closely. The material and staircase influence which approach suits the project.
This calculator does not attach a fixed extra length to a style name. Use the intended fitted path or a measured profile allowance. Tell the fitter how the numbers were obtained so that the same nose is not counted once in the measurement and again as extra material.
Pattern, finishing and reserve are separate
End finishing may need extra material for the chosen top and bottom treatment. Enter the combined amount for both ends. The pattern field is a separate total agreed for aligning the actual design. Entering a repeat size alone does not prove how many repeats the installation will use.
The optional reserve is applied to the path plus both allowances. For example, if the measured path already includes all agreed fitting spare, adding that same spare again would overstate the order. The breakdown makes each addition visible so you can check it.
Common questions
Can I use this for turning stairs or a landing join?
The tool estimates one straight run at one finished width. It does not design a turn, cut a mitre, arrange a join or match a pattern across separate flights. Adding their lengths together may help an early budget, but it is not a cutting plan. Use an installation-specific layout for winders, curved steps or a change of direction.
Does it calculate carpet from a wider roll?
No. The order length assumes a ready-width runner or one continuous cut supplied at the stated finished width. Broadloom carpet may require several strips, edge finishing, direction control and permitted joins. Area alone cannot determine the roll length for that cutting arrangement.
Can I subtract a leftover piece I already own?
Do not simply subtract its length from a continuous-run requirement. A short piece only helps if a planned join is suitable for the product, pattern and location. This calculator intentionally keeps the required continuous length intact.
What does the price include?
The rounded order length multiplied by the price per selected length unit. The price must apply to the chosen finished width. Binding, underlay, grippers, installation, delivery and taxes not already included in that price are separate. A square-metre price or price per 10 cm unit must be converted to the selected full length unit before entry.
Does any runner work on stairs?
Check the exact product's stair suitability and fitting instructions. Alternative Flooring's installation guidance distinguishes materials and fitting methods. Quantity calculations do not choose the underlay, fixings or installation method.
Which calculator helps with the rest of the room?
Use the flooring calculator for flat floor packs, the baseboard calculator for skirting lengths or the paint calculator for wall finishes. Each tool uses a different material model.
