Rise and Run

Definition

Rise is the vertical height of a flight (floor to floor, including finishes). Run is the total horizontal going. A comfortable target riser is often 7–7¾ in (178–197 mm). The tool rounds total rise ÷ target riser to a whole number of risers; treads are one fewer because you step onto the landing. Stringer length is the hypotenuse of total rise and total run. Blondel’s 2R + T is a comfort check, not a code.

Calculators that use this

• Carpentry & framing

  Stair Rise and Run Calculator

  Size stair risers, treads and stringer length from total rise and a target step height. Works in inches or millimetres.

• Carpentry & framing

  Roof Pitch & Rafter Length Calculator

  Calculate common rafter length, pitch angle, rise and overhang from building span and a rise-per-12 pitch.