Stair Calculator
Work out how many steps you need, how big they should be and how much space your staircase will take.
Fine-tune dimensions +
Check available space +
Height of each step.
Horizontal distance between step edges.
Compare riser counts
Three ways to divide the same height.
Download plan and section.
Architectural resources for plans, sections, elevations and more ↗
Stair dimensions, without the guesswork
Enter the floor-to-floor height, stair width and shape. The calculator gives you a layout, nearby riser options and drawings you can download.
A starting point
Automatic mode aims for a 175 mm rise. The going is calculated using 2 × rise + going = 630 mm. These are design assumptions, not a building code.
Count risers and treads separately
A flight with 16 risers has 15 treads when the upper floor is its final landing. Two flights are counted separately. Calculations keep full precision. Displayed values are rounded.
Before you build
This tool calculates layout geometry. Headroom, structure, handrails, guards, access and local code compliance are not checked.
A few useful things to know
What is the difference between rise and going?+
Rise is the vertical height of one step. Going is the horizontal distance between successive step edges. It is not the full tread depth when a nosing projects over the step below.
What does the footprint include?+
The flights and any intermediate landing. A U-shaped stair also includes the gap between flights. Walls, finishes around the enclosure, handrail projections, and clear arrival spaces at the top and bottom are not added.
Why is the section unfolded?+
For L-shaped and U-shaped stairs, the section follows both flights and the landing in one straight line. Its horizontal length is the developed route, not the plan footprint.
Can I use the drawing in CAD?+
Yes. The DXF contains plan and section at 1:1 in millimetres, with separate layers for stair geometry, dimensions and annotations. It is a layout drawing, not a structural or fabrication design.