Stair Riser and Tread Calculator
Calculate the number of risers, actual riser height and tread depth from total rise and available run.
Formula
Planning estimate. Check product specifications and local requirements before purchasing.
Worked example: Stair Calculator
Measurements in this example
| Total rise | 280 cm |
|---|---|
| Available horizontal run | 390 cm |
| Maximum riser height | 18 cm |
Calculated quantities
| Risers | 16 |
|---|---|
| Actual riser height | 17.5 cm |
| Tread depth | 26 cm |
What to check
This calculation uses: Total rise, Available horizontal run, Maximum riser height. It returns: Risers, Actual riser height, Tread depth.
Measure finished levels rather than unfinished structure. Keep landing lengths, headroom and clear width as separate checks.
A geometrically possible result may not comply with accessibility or stair rules. Check the current local requirements.
Do not alter one riser to absorb an error. Consistent finished dimensions are essential for comfortable and safe use.
Use the units beside each field. The values in the worked example are starting inputs; replace them with your measurements and the specifications of your material.
Compare alternatives
Open a tool, enter your measured dimensions, then save an estimate. Keep another version if you want to compare products or allowances.