OneTool

Stair Stringer Calculator

Rise and tread assumptions → stringer layout sketch.

Floor-to-floor height.

  • Number of risers

    13

  • Actual riser height

    7.38 in

  • Number of treads

    12

  • Total run

    120.0 in

  • Stringer length (min.)

    153.7 in

    Buy stock at least this long — round up for the notch cuts and stock lengths available.

What is this tool?

Stair layout starts from total rise. Dividing by a target riser height gives the number of risers; treads are typically one fewer. Stringer length follows from rise and total run. Common IRC residential ranges are flagged for reference — always confirm local code before building.

How to use it

  1. Enter total rise and target riser/tread dimensions.
  2. Read riser count, actual rise, run, and stringer length.
  3. Verify against local building code before cutting.