Stair Rise / Run

Actual riser, total run, angle, and stringer slope from total rise, riser count, and tread. Treads default to risers − 1.

Construction & Trades

Actual riser, total run, angle, and stringer slope from total rise, riser count, and tread. Treads default to risers − 1.

App id: STAIRS-01. Reference version 1.0.

How to fill it

Fill the inputs. The tool shows the outputs.

On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.

Formula

rise = totalRise / n; run = tread × (n − 1); θ = atan(rise / tread)

Inputs

Name	Unit
Total rise (optional)	`in`
Number of risers (optional)	`1`
Tread / run	`in`
Number of treads (optional)	`1`
Riser height (optional) (optional)	`in`

Outputs

Name	Unit
Actual riser (hero result)	`in`
Total run	`in`
Stair angle	`deg`
Risers	`1`
Treads	`1`
Stringer slope length	`in`

Diagnose

Observations are context. They do not pass or fail a structure. See Diagnose.

When	Observation	Severity
`deg > 40 or riser in > 8`	Steep stair geometry	caution

Provenance

Does not check maximum riser or minimum tread from any building code.