Stair Calculator

FREE PROJECT PLANNING TOOL

Turn a floor-to-floor height into a practical first-pass stair layout. The calculator estimates riser count, exact riser height, tread count and total horizontal run from the dimensions you enter.

How the stair calculator works

The tool divides total rise by a target riser height, rounds to a whole number of equal risers, then recalculates the exact height. For a typical straight flight, tread count is one fewer than riser count and total run equals tread count multiplied by tread depth.

  1. Measure finished floor to finished floor—not the rough opening.
  2. Enter a target riser height and intended tread depth.
  3. Review the recalculated equal riser height, tread count and total run.
  4. Compare the result with your local code and the available opening before building.

FREE WALL CALCULATOR

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Worked planning example

For a 108 in total rise and a 7.5 in target, the tool tests the nearest whole-riser layout and reports the exact equal height. A 10 in tread depth is then multiplied by the resulting tread count to estimate run.

Stair geometry affects safety and is regulated. Finished flooring thickness, landings, nosing and headroom can change the real layout. Use this calculator for early planning, then have the final design checked by a qualified professional and the local authority.

Frequently asked questions

Why did the riser height change?

A staircase needs a whole number of equal risers, so the target is used to choose a count and the exact height is recalculated.

Is tread count always one less than riser count?

For a typical straight flight between floors it usually is, because the upper floor acts as the final walking surface. Landings and special layouts need separate checks.

Does this verify building code?

No. Code limits vary by location and occupancy; verify rise, run, headroom, width, guards and handrails locally.

Turn the estimate into a finished wall

Save the measurements, verify them on site and compare materials before ordering. Trim Wall Haus offers pre-cut wall molding options and project support for cleaner DIY planning.

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Planning estimate only. Verify field measurements, product dimensions and local requirements before cutting or installation.

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