Why is tread count one less than riser count?

This planner assumes a straight stair finishing at a top landing. You step onto the landing after the final riser, so the stair run has one fewer tread than risers.

What happens if I lower the maximum rise per step?

The calculator adds risers until the exact rise per step falls at or below your limit. More risers usually means a gentler stair, but it also means more total steps to build.

What happens if I make the treads deeper?

Deeper treads increase total run because each tread adds more horizontal distance. The stair usually becomes shallower, and the stringer gets longer.

What does stringer length represent here?

It is the straight-line diagonal from the bottom of the stair to the top landing in this simple side profile. It helps you estimate the overall stringer geometry before detailed cut layout.

How is this different from triangle math or material estimators?

Triangle calculators solve abstract side relationships, and material estimators count boards, sheets, or volume. This tool turns level-to-level rise plus stair assumptions into a practical straight-stair layout you can judge for fit.

Does this confirm code compliance?

No. Local building rules vary by project and location. Use this calculator to plan geometry, then confirm your final stair design against the rules that apply where you are building.

Stair Calculator

Plan a straight staircase from total rise, target maximum rise per step, and tread depth. Get a practical layout with riser count, exact rise per step, tread count, total run, stringer length, and stair angle before you cut stringers or buy materials.

Units

Total Rise

Maximum Rise per Step

Tread Depth

Examples

Enter values above to see results