How to use this calculator
Stair geometry starts from total rise: divide it into equal risers no taller than your chosen maximum, then count treads by the landing convention you state. Equal risers matter for safety and comfort, which is why the tool equalizes them instead of leaving a short or tall final riser.
Enter your own figures in the form above. A blank field is treated as missing — not as zero — so the tool will ask you to complete it. A genuine zero is accepted where it makes sense (for example, no HOA dues). Press Calculate for a breakdown, Load worked example to fill in the example below, or Reset to return to the defaults.
Formula and assumptions
Risers = total rise ÷ chosen maximum riser, rounded UP. Actual riser = total rise ÷ risers (equal risers). Treads = risers − 1 under the top-landing convention, or risers under the top-step convention. Total run = treads × going. Slope angle = arctan(actual riser ÷ going).
Worked example
Worked example: total rise 108 in, chosen maximum riser 7.5 in, going 10 in, top landing as final riser. Risers: 108 ÷ 7.5 = 14.4, rounded to 15 risers at 7.2 in each; treads 14; total run 140 in.
Use the Load worked example button above to reproduce this example in the form, then change one input at a time to see what drives the result.
Limitations and common mistakes
No universal US code pass/fail is given: riser/tread limits, headroom, landing size, handrails, guards and stair width depend on the locally adopted code and the stair’s use. This is geometry for planning and discussion, not a code compliance check or a full stair design.
Frequently asked questions
Why equal risers?
Because an unexpected riser height is a trip hazard. Equalizing spreads the remainder evenly instead of dumping it on one step.
What is the landing convention?
Whether the upper floor/landing itself serves as the last “step up.” If it does, there is one fewer tread than risers; if a top step is built, treads equal risers.
Can I check code compliance here?
No. Check the code adopted in your jurisdiction and have the stair designed and inspected as required locally.
Sources
No external price, product or market data is used on this page. Every price, density, coverage and rate is a figure you enter, or a clearly labelled illustrative default in the form. Check product labels and supplier quotes for the figures that apply to your job.
Estimates only. Results from this calculator are not a loan offer, appraisal, engineering design, equipment selection or contractor quote.