Stair Rise Calculator
Estimate riser count and individual rise height for any staircase.
Estimate riser count and individual rise height for any staircase.
Stair rise is the vertical height of each step, measured from the top of one tread to the top of the next. Total rise is the full vertical distance the stairs must climb, from the lower finished floor or landing to the upper finished floor or deck surface. Dividing total rise into equal steps gives the number of risers and the height of each one, which are the first numbers needed to lay out stringers for interior stairs, deck stairs, or porch steps.
Comfort and code set the target. Most residential stairs use risers between about 7 and 7.75 inches, and the International Residential Code, adopted in many US jurisdictions, caps riser height at 7.75 inches and requires all risers in a flight to be within 3/8 inch of each other. Uneven steps are a well-known trip hazard, which is why the total rise must be divided evenly rather than stacking full-height steps and leaving a short one at the top or bottom. Measure total rise from finished surfaces, accounting for flooring or decking that has not been installed yet, and measure at the spot where the stairs will land, since ground and floors are rarely perfectly level. Local codes can differ, so confirm requirements with your building department.
To use this stair rise calculator, enter the total rise in inches and your target rise per step (7.5 inches by default). The tool divides total rise by the target, rounds to the nearest whole number to get the riser count, then divides total rise by that count to find the actual height of each riser. The result shows the number of risers and the exact rise per step. If the actual rise comes out above your code limit, add one riser and recalculate.
7 to 7.75 inches is typical for residential stairs. Code varies by jurisdiction.
9 to 11 inches is standard. The sum of one riser + one tread should be 17–18 inches.
Results are estimates for planning purposes. Verify with product labels and local requirements before purchasing materials.
Measure the total rise — the vertical distance from the lower floor to the upper floor. Divide by your target riser height (7–7.75 inches is standard) and round to the nearest whole number. That gives you the riser count.
Formula: Risers = ROUND(Total rise ÷ Target rise height)
Divide total rise by the riser count to get the actual rise per step. All risers in a flight of stairs must be equal within 3/8 inch — uneven steps are a trip hazard and a code violation.
| Total rise | Target 7 in | Target 7.5 in | Target 7.75 in |
|---|---|---|---|
| 42 in | 6 risers × 7.0 in | 6 risers × 7.0 in | 5 risers × 8.4 in* |
| 54 in | 8 risers × 6.75 in | 7 risers × 7.71 in | 7 risers × 7.71 in |
| 90 in | 13 risers × 6.92 in | 12 risers × 7.5 in | 12 risers × 7.5 in |
| 108 in | 15 risers × 7.2 in | 14 risers × 7.71 in | 14 risers × 7.71 in |
*Exceeds code maximum of 7.75 in — adjust riser count up.
7 to 7.75 inches is the most comfortable range for residential stairs. The IRC (International Residential Code) allows a maximum rise of 7.75 inches.
Rise is the vertical height of each step. Run (or tread depth) is the horizontal depth — the part your foot lands on. Standard run is 10–11 inches. The sum of one rise + one run should be 17–18 inches.
Measure from the deck surface to the ground (total rise). Divide by your target rise (7 inches is common) and round to the nearest whole number. That gives you the number of risers.
Risers are the vertical faces between steps — the height of each step. Treads are the horizontal surfaces — the part you step on. A straight stair with 10 risers typically has 9 treads, because the upper floor acts as the final step.
Yes in many jurisdictions, but openings must be small enough that a 4-inch sphere cannot pass through — important for child safety. Check your local code.
The calculator rounds to a whole number of risers and then splits the total rise evenly. For 100 inches at a 7.5-inch target, 100 ÷ 7.5 = 13.3, which rounds to 13 risers at about 7.69 inches each. With 47 inches, it rounds to 6 risers at 7.83 inches, which is over the 7.75-inch IRC limit, so use 7 risers at about 6.71 inches instead.
Total run is the number of treads times the tread depth. In a typical flight where the upper floor acts as the top step, there is one fewer tread than risers, so 14 risers with 13 treads at 10 inches gives a total run of 130 inches, or about 10 feet 10 inches.
Measure straight down from the top of the finished deck surface to the spot where the bottom step will land, such as a concrete pad or the ground. If the ground slopes, measure at the actual landing point, because the rise there can differ from the rise right at the deck edge.