Measure the total rise
Measure vertically from the lower finished surface to the upper finished deck, floor, or landing height.
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Free Stair Stringer Calculator
A stair stringer calculator converts total rise into equal risers, tread count, total run, stringer length, and stair pitch. Use this free layout calculator to plan deck stairs, shop stairs, or porch steps before marking a stringer board.
Stair dimensions
Measure finished surfaces before laying out the stringer.
Cut layout
Stair stringer estimate
Risers
5
7-3/16 in each
Treads
4
10 in run
Total run
3 ft 4 in
horizontal footprint
Pitch
41.99 deg
stock fits
| Total rise | 3 ftFinished floor or landing height |
|---|---|
| Riser cut | 7-3/16 in5 equal risers |
| Tread cut | 10 in4 treads before landing |
| Total run | 3 ft 4 inHorizontal stair footprint |
| Stringer length | 4 ft 5-13/16 in3 stringers recommended |
Layout notes
- Mark 5 risers at 7-3/16 in and 4 treads at 10 in.
- The stair run is 3 ft 4 in with a pitch of about 41.99 degrees.
- Add a 1 in nosing only after confirming your local code and tread material.
How to use the stair stringer calculator
Choose a target riser height
Enter the riser height you want the calculator to work toward. The calculator will divide the total rise into equal risers.
Set tread depth and stock length
Add the tread run, nosing, available stringer stock length, and number of stringers so the layout can flag short stock.
Review the cut layout
Use the calculated riser cut, tread cut, total run, stringer length, pitch, and notes as a planning check before cutting.
Stair stringer calculator FAQ
How do you calculate stair stringer layout?
Divide the total rise by a target riser height, round up to a whole number of risers, then divide the total rise by that riser count. The tread count is usually one less than the riser count, and total run is tread count times tread depth.
What is a comfortable stair riser height?
Many residential stairs use risers around 7 inches to 7-1/2 inches. Local code can vary, so confirm the maximum riser height and minimum tread depth before cutting permanent stairs.
How many treads do I need for a stair stringer?
Most straight stair layouts have one fewer tread than risers because the upper deck or landing acts as the final step surface.
How long should my stair stringer board be?
The stringer board must be longer than the diagonal distance from the bottom of the stair to the top landing. This calculator compares that diagonal stringer length with the stock length you enter.
Can I use this for deck stairs?
Yes. It is useful for deck stair planning, but ledger attachment, footings, handrails, landings, and local building code still need separate review.
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