Stair Calculator
Calculate the number of steps, actual riser height, and recommended tread depth for a staircase.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter your total floor-to-floor height and desired riser height to find the number of steps and recommended tread depth.
150-180mm is a comfortable riser height for most residential stairs.
Your result
17
Number of steps
Actual riser height176.5
Recommended tread depth277
AI explanation
Formula
Number of steps = round(total rise ÷ desired riser); actual riser = total rise ÷ number of steps; tread ≈ 630mm − 2 × actual riserWorked example
3000mm floor height, 175mm desired riser
| Field | Value |
|---|---|
| Total rise / floor-to-floor height (mm) | 3000 |
| Desired riser height (mm) | 175 |
| Number of steps | 17 |
| Actual riser height | 176.5 |
| Recommended tread depth | 277 |
Assumptions
- Uses the widely cited "2 × riser + tread ≈ 630mm" comfort rule of thumb for a proportionate, comfortable stair — a design guideline, not a building-code requirement. Check your local building code for minimum/maximum riser and tread dimensions.
Frequently asked questions
Why is the actual riser different from my desired riser?
The number of steps must be a whole number, so the total rise is divided evenly across that many steps — the actual riser is usually very close to, but not exactly, your desired value.
What is a comfortable riser and tread size?
150-180mm risers with 250-300mm treads are typical comfort ranges for residential stairs, following the "2×riser + tread ≈ 630mm" rule of thumb.
I need the diagonal stringer length too — is there a calculator for that?
Yes — see the Stair Stringer Calculator, which computes the stringer length from the total rise and run.