Stair Calculator
How many steps do you need? Enter the total height to climb.
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Actual riser height—
Number of treads—
Total horizontal run—
Shop stair stringers & treads →
How this calculator works
It divides your total floor-to-floor rise by a comfortable target riser height to get a whole number of steps, then recalculates the exact riser height and the total horizontal run.
Worked example — a 108 inch total rise:
108 ÷ 7.5 ≈ 14 steps → riser height 7.71 in, 13 treads, 130 in of run.
Keep every riser equal
Building codes require all risers within a staircase to be nearly identical (within 3/8 inch) — uneven steps are a trip hazard. That’s why we round to whole steps and recompute.
Frequently asked questions
What is a comfortable stair riser height?
About 7 to 7.75 inches; most codes cap risers at 7.75 in.
How do I calculate number of stairs?
Divide the total floor-to-floor height by your target riser height and round to a whole number.
Planning a decking project
Board dimensions are nominal sizes and can vary by product. Include joist layout, picture framing, stairs, fascia, seams, and the direction of the boards in a final takeoff. Structural sizing and ledger details should be checked against local code or reviewed by a qualified builder.
How to use this estimate
- Measure the project in the units shown and recheck your measurements before ordering.
- Use the waste allowance as a planning buffer, not as a substitute for a detailed material takeoff.
- Compare the result with the package yield, coverage, or weight listed by your supplier.
- Prices are user-entered estimates and may change by location, product, delivery, and season.
Accuracy and limitations
Calculapedia provides educational planning estimates. It does not inspect your site, select products, guarantee quantities, or replace a contractor, engineer, architect, building official, or supplier. Confirm the final quantity and any safety or code requirements before buying or building.