Stair Stringer
Lay out a staircase stringer from rise and run.
About Stair Stringer
The combined rise set and run set form a right triangle whose hypotenuse is the long edge of the stringer board. The length of a 2x stringer decides whether one standard board spans a staircase or you need to splice it.
Formula
Stair Stringer
Stringer = sqrt(rise set^2 + run set^2)
- run set
- Horizontal travel equals treads x tread run
Worked example
With the default values below, Stair Stringer returns Riser Count of 15. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total riseminimum 6 in
- 105 in
- Riser heightminimum 4 in
- 7 in
- Tread runminimum 6 in
- 10 in
Results
- Riser Count
- 15
- Rise Set
- 105.0 in
- Run Set
- 140.0 in
- Stringer Length
- 14.58 ft
Step by step
- 1Values used
- 2Stair Stringer
- 3Riser Count= 15
- 4Rise Set= 105.0 in
- 5Run Set= 140.0 in
- 6Stringer Length= 14.58 ft
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Stair Stringer calculated?
Stringer = sqrt(rise set^2 + run set^2) The combined rise set and run set form a right triangle whose hypotenuse is the long edge of the stringer board.
Why does Stair Stringer matter?
The length of a 2x stringer decides whether one standard board spans a staircase or you need to splice it.
What values do I need to enter?
This calculator takes 3 inputs: Total rise, Riser height, Tread run. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.