Stairs Calculator — Rise, Run & Step Count
Enter the total rise and your target riser height to get the number of steps and the total run. No sign-up, no data stored.
Staircase layout
How staircase steps are calculated
The math is simple and exact — no assumptions to adjust for:
- Total rise = vertical height between finished floors (in inches).
- Riser count = total rise ÷ riser height, rounded up.
- Actual riser = total rise ÷ riser count (keeps every step equal).
- Treads = riser count − 1 (the top landing is the last step).
- Total run = treads × tread depth.
- Stringer length = the diagonal from floor to floor, using the rise and run.
Building codes require all risers in a stair to be equal. This calculator divides the rise evenly so every step is identical — that's the comfort and safety standard. Check your local code for minimum tread depth and maximum riser height.
Stair layout chart
Common riser heights and their step counts.
Risers for common floor-to-floor heights
| Total rise | Risers @ 7" | Treads | Run @ 10" |
|---|---|---|---|
| 8 ft (96 in) | 14 | 13 | 130 in |
| 8.5 ft (102 in) | 15 | 14 | 140 in |
| 9 ft (108 in) | 16 | 15 | 150 in |
| 10 ft (120 in) | 18 | 17 | 170 in |
Comfort rule of thumb
| Riser | Tread | Sum |
|---|---|---|
| 7 in | 10 in | 17 in ✓ |
| 7 in | 11 in | 18 in ✓ |
| 7.5 in | 10 in | 17.5 in ✓ |
Last updated: October 2026 · Riser and tread values reflect common US residential practice. Always check your local building code, which sets minimums and maximums, before building.
Stairs calculator FAQ
Assuming an 8-ft rise to the finished floor, that's 14 steps at a 7-inch riser (13 treads). If the rise is closer to 9 ft, you'll have 16 risers and 15 treads. Measure your actual floor-to-floor height.
Most single-floor rises (8–9 ft) work out to 14–16 steps. Divide your total rise in inches by 7 and round up — that's the number of risers.
The riser is the vertical height of each step; the tread is the horizontal part you step on. One tread per riser, except the top landing, which counts as the last step — so treads = risers − 1.
Divide the total rise in inches by the number of risers you want. For a 108-inch rise split into 15 steps, each riser is 108 ÷ 15 = 7.2 inches.
Some codes require a landing if the stair rises more than a certain distance (often every 12 feet of vertical rise). Landings also break up long runs for safety and comfort. Check your local code.