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The total vertical height the stair climbs, floor to floor.
Finished floor to finished floor, which is not the same as slab to slab — the finishes at top and bottom are frequently different thicknesses and the difference lands entirely in the first or last riser. Measure it on site rather than from a section if the floors are built: a stair fabricated to a drawing that was 20 mm out arrives with every riser right and the top one wrong.
The total horizontal distance the stair covers.
The going, in plan, from the face of the bottom riser to the face of the top one. It is usually the constrained dimension — the stair has to land somewhere — and together with the rise it fixes the pitch. If the run is not free, check the resulting riser and going against the code's limits before fabricating: a stair that fits the hole and fails the going rule is a stair that comes out again.
Stringer length
16.4 ft
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Structural Steel Stair Stringer Length Calculator: 16.4 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Stringer length = √(total rise² + total run²), standard right-triangle geometry applied to a stair stringer's diagonal slope
Inputs used
- Total Rise
- 10 ft
- Total Run
- 13 ft
What this calculation does not cover
- The figure is one stringer. A flight normally carries a stringer each side, and a wide flight adds an intermediate one, so the steel take-off is this length multiplied by the number of stringers; treads, nosings, landing framing and handrail posts are separate items this number does not include.
- It assumes a single straight flight between the two levels. Where the stair breaks at an intermediate landing or turns on winders, the total run entered must be the run of one flight alone: including the landing depth returns a diagonal longer than any member that actually gets fabricated, the real stringers stopping at the landing beam and restarting above it.
- This is geometry, not a structural check. It does not select the channel or plate, and it does not test the stringer for bending, deflection or lateral-torsional buckling as an inclined beam spanning between its end connections, even though a longer diagonal is a longer unsupported span. The stair live load, the concentrated tread load and the deflection limit that govern the section come from the code in force, not from this length.
- Total rise and total run are taken as given and never divided into risers and treads, so nothing here tests riser uniformity, tread going, headroom or pitch. A 3 m rise over a 4 m run is a 36.9 degree pitch, but the same formula returns 10.05 m just as readily for a 10 m rise over a 1 m run, an 84.3 degree pitch no occupied stair would be built to; the permitted maximum pitch is jurisdictional and is not applied to your entries.
- The length says nothing about whether that member can be rolled, coated or delivered in one piece. At the top of the accepted input range, a 10 m (33 ft) rise over a 15 m (49 ft) run, the result is 18.03 m (59 ft), which is beyond ordinary mill stock lengths, beyond most galvanising baths and beyond routine road transport, so a splice or site joint is implied that the geometry never shows. Bath capacity and available stock lengths are supplier-specific.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Part of a bigger job
Or plan the space itself: measure it once, doors and windows included, and this figure comes back worked out on that space, with what goes with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-02 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Stringer length = √(total rise² + total run²), standard right-triangle geometry applied to a stair stringer's diagonal slope
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