Stair Rise Calculator
Estimate riser count and individual rise height for any staircase.
Stair Estimate: —
Stair FAQ
What is a comfortable riser height?
7 to 7.75 inches is typical for residential stairs. Code varies by jurisdiction.
What is the ideal tread depth?
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.
How to calculate stair rise and riser count
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.
Stair code requirements (IRC)
- Maximum rise: 7.75 inches per riser.
- Minimum run (tread depth): 10 inches.
- Minimum headroom: 6 ft 8 in at all points above the stair.
- Handrail required on stairs with 4 or more risers.
- All risers must be within 3/8 inch of each other — consistent rise is critical for safety.
Frequently asked questions
What is a comfortable stair rise height?
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.
What is stair run and how is it different from rise?
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.
How do I calculate the number of stairs for a deck?
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.
What is the difference between risers and treads?
Risers are the vertical faces between steps — the height of each step. Treads are the horizontal surfaces — the part you step on. A stair with 10 risers has 10 treads.
Are open risers allowed by code?
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.
Related tools
- Roof Pitch Calculator — calculate pitch ratio and angle
- Square Footage Calculator — calculate landing and floor area
- Concrete Bag Calculator — estimate concrete for stair footings
QuickJobTools is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.