Stair Stringer Calculator for Risers, Treads & Cut Layout
Use this stair stringer calculator to calculate risers, treads, total run, stringer length, and cut layout from total rise and available run constraints. Core stair layout math is free - go Pro for custom limits, riser-count comparisons, cut marks, and a copyable stringer plan.
6 risers at 7 in with 5 treads gives 52.50 in total run.
Each riser is 7 in with 5 treads at 10.50 in.
Pro unlocks custom constraints, riser-count comparisons, cut marks, and a copyable stringer plan.
Unlock with ProPro unlocks custom constraints, riser-count comparisons, cut marks, and a copyable stringer plan.
Unlock with ProPro unlocks custom constraints, riser-count comparisons, cut marks, and a copyable stringer plan.
Unlock with ProFree to use. Pro when you need more.
One oftenoriginal Pro membership unlocks the pro features on every tool.
Free
$0- ✓Riser count and actual riser height
- ✓Tread count and tread depth inputs
- ✓Total run checked against available run
- ✓Stringer length and stair angle
- ✓Deck, porch, and interior starting presets
- ✓No sign-up required
oftenoriginal Pro
$9/month- ✓Everything in Stair Stringer Calculator, unlocked
- ✓Custom riser and tread constraints
- ✓Nosing and stringer count inputs
- ✓Riser-count comparison table
- ✓Step-by-step cut layout
- ✓Copyable stringer plan
Stair Stringer Calculator — frequently asked questions
How does this stair stringer calculator work?+
It tests possible riser counts against your total rise, available run, tread depth, and riser limits, then picks the layout closest to your target riser height that still fits the run.
How many treads does a stair need?+
For a typical straight stair, the tread count is one less than the riser count because the upper floor or deck surface acts as the final landing.
Can I use this for code-compliant stairs?+
The calculator includes common stair planning constraints, and Pro lets you customize riser and tread limits. Always check local building code and site conditions before cutting lumber.
Is my stair project data sent to a server?+
No. Total rise, available run, tread depth, riser limits, stringer length, and cut layout are calculated entirely in your browser.
Related tools
More free tools from the oftenoriginal toolbox — no sign-up required.
Get new free tools monthly
We ship a new free tool nearly every day. Get the best of the month in one short email.