Worked example: Stair Calculator
280 cm rise. This fixed reference example shows one complete scenario; the interactive results above use your current inputs.
View the example inputs
- Measurement units
- Metric
- Total floor-to-floor rise
- 280 cm
- Chosen maximum riser height
- 18 cm
- Chosen tread depth
- 28 cm
| Calculated quantity | Example result |
|---|---|
| Number of risers | 16 |
| Equal riser height | 17.5 cm |
| Number of treads | 15 |
| Horizontal run | 420 cm |
Turning measurements into a materials estimate
Separate length, area, depth and volume
Area describes a surface, while volume includes depth or thickness. A small depth-unit error can multiply an order substantially, especially when inches, centimeters, feet and meters are mixed. Confirm each dimension and use the unit selector to convert an existing physical measurement.
A net geometric quantity and an ordering quantity answer different questions. Waste, cuts, overage and packaging can make an order larger than the idealized area or volume. The allowance is already included when a result says including waste; do not add it a second time.
Use product-specific yields and design requirements
Bag yield, bulk density, compaction and coverage vary between materials and suppliers. A volume-to-bag conversion needs the product’s specified yield, and an estimated mass depends on the density you enter. A conservative tile grid is not an optimized cutting layout.
A quantity calculator does not verify structural strength, local code, headroom, load capacity or suitability of a mix. Review the stated shape assumptions and supply the dimensions required by the actual design before ordering.
Formula and calculation method
Risers=ceiling(total rise/chosen maximum riser). Actual riser=total rise/risers. Treads=risers−1, assuming the upper floor is the final landing. Run=treads×tread depth.
Scope and Limitations
- Does not check local building rules, headroom, landings, handrails, structural strength or accessibility. Enter dimensions required by your local design.
Reference Sources
Frequently asked questions
How does this calculator work?
Risers=ceiling(total rise/chosen maximum riser). Actual riser=total rise/risers. Treads=risers−1, assuming the upper floor is the final landing. Run=treads×tread depth.
What assumptions should I check?
Does not check local building rules, headroom, landings, handrails, structural strength or accessibility. Enter dimensions required by your local design.
Can I save or print this calculation?
Use Copy link with inputs to reproduce the scenario, Download results for a text record, or Print. Where a schedule is shown, its CSV download includes every row.
What happens when I change measurement units?
The linked unit selector converts the existing measurement so it represents the same physical quantity. Entering a different number after switching units changes the underlying input. The result’s own units are shown beside its value.