Calculators
Stair Calculator
Estimate stair steps, riser height, tread depth, stringer length, and stair angle from total rise and run locally in your browser.
Enter the total stair rise and total stair run in inches plus a target riser height to estimate the step count, actual riser height, tread depth, stringer length, and stair angle. The calculation runs locally in your browser; your values are not uploaded or stored.
Steps are rounded from total rise divided by the target riser height, then the actual riser is total rise divided by steps and the tread is total run divided by steps. The stringer is the straight length from the bottom to the top of the stair. This is a planning layout only and does not check local building codes for riser, tread, headroom, handrail, or landing rules, so confirm the design with your local code and a qualified builder before cutting materials.
Plan a stair layout without uploading anything.
Enter the total stair rise and total stair run in inches plus a target riser height to see the step count, actual riser height, tread depth, stringer length, and stair angle. Everything runs locally in your browser, so your values are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What formulas does the stair calculator use?
It rounds steps = total rise / target riser height, then uses actual riser = total rise / steps, tread = total run / steps, stringer = square root of (rise squared + run squared), and angle = arctangent of (rise / run). For example, a 42 inch rise with a 7 inch target gives 6 steps with a 7 inch riser.
Which inputs are accepted?
Enter total rise and total run greater than zero through 1000000000 inches and an optional target riser height from 1 to 12 inches (7 inches when blank). Missing or non-numeric entries show a clear error instead of a result.
Does this check building codes?
No. It is a geometric planning layout only and does not check local codes for riser height, tread depth, headroom, handrails, or landings, so confirm the design with your local code and a qualified builder before cutting materials.
Do my values stay private?
Yes. The calculation and copy action run locally in your browser. CodeASystem does not upload or store the values you enter.