Enter total rise, available run, and preferred step dimensions for code checks. See stringer length, pitch angle, cut marks, and material summary instantly here.
| Scenario | Total Rise | Total Run | Risers | Treads | Riser Height | Tread Depth | Pitch | Stringer Length |
|---|---|---|---|---|---|---|---|---|
| Residential | 2800 mm | 3750 mm | 16 | 15 | 175.0 mm | 250.0 mm | 36.87° | 4683.7 mm |
| Compact | 2400 mm | 3000 mm | 14 | 13 | 171.4 mm | 230.8 mm | 38.66° | 3841.9 mm |
| Gentle | 2700 mm | 4500 mm | 15 | 14 | 180.0 mm | 321.4 mm | 30.96° | 5244.0 mm |
Measure finished-floor to finished-floor height, not rough framing. Include underlayment, tile, hardwood, and any finish buildup. A 15 mm flooring change can shift every riser by nearly 1 mm across a 15-riser stair, which is noticeable and may fail consistency checks.
Riser count controls comfort and safety. Typical residential risers often fall roughly in the 150–200 mm range (or about 6–8 in). This calculator lets you target a riser height or lock a riser count, then reports the exact riser height that matches the total rise.
Available run is the horizontal space the stair can occupy. With a fixed run, tread depth becomes total run divided by the number of treads (usually risers minus one). If you instead choose a tread depth, the calculator updates total run so you can see the footprint required.
A common comfort check is the step “feel” relationship: 2R + T (two risers plus one tread) near 600–650 mm, depending on local practice. Use the reported riser height and tread depth to evaluate this quickly and adjust either value to improve walking rhythm.
Pitch is the slope of the stair, computed from rise divided by run. A higher pitch saves space but can feel steep and reduce safety margins. Compare your pitch angle to your project requirements, then refine riser count or tread depth until the stair fits both space and usability goals.
Stringer length is the diagonal cut line length: √(rise² + run²). Use it to confirm stock size, splices, or engineered members. Add a waste allowance for end trimming and checking your layout lines. The material total multiplies the length by your stringer count.
Nosing affects the tread projection at each step and helps with marking references. It does not change the structural run, but it matters for layout, finish alignment, and comfort. The calculator reports tread projection as tread depth plus nosing so you can plan consistent overhang and finish details.
After calculating, verify that every riser is identical after finishes, and confirm landing thicknesses and framing tolerances. Use the warnings for minimum and maximum thresholds to flag out-of-range steps early. Print or export results so installers can confirm counts, sizes, and angles on site.
1) Why are treads usually one less than risers?
A stair starts on the lower floor and finishes on the upper floor. Each riser raises you to the next level, while the last riser lands on the top floor without needing an extra tread.
2) What if my riser height is not a “nice” number?
That is normal. Consistency matters more than a round value. Use the calculated riser height for all steps, and re-check after finish thickness changes to keep all risers uniform.
3) Should I enter rough or finished dimensions?
Use finished dimensions whenever possible: finished floors, finished landings, and final tread thickness. If you must use rough framing numbers, revisit the inputs once finishes are confirmed.
4) How do I use the pitch angle result?
Pitch summarizes steepness. If the angle feels high for the space, increase total run or reduce riser height by increasing riser count. Always compare to your local requirements and project constraints.
5) Does nosing change the total run?
No. Nosing changes the visible tread projection and marking reference, but the structural run is based on tread depth multiplied by tread count. Use projection for finish alignment and comfort checks.
6) How many stringers should I use?
It depends on stair width, tread material, and loading. Wider stairs and thinner treads typically need more stringers. Use your design guidance, then enter the count to estimate total stringer length.
7) What is a practical waste allowance?
Many builders add a small percentage for trimming and defects. If you expect splices, knots, or field adjustments, increase the waste value. The material total updates automatically with your chosen percentage.
Measure twice, cut once, and build safer stairs always.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.