Quickly get critical numbers for setting out stairs. A graphical representation will also be generated for you.

June 2026 Update

I updated this tool to also check the stair’s design against the National Construction Code. If they meet the code, it will show a green tick. If they don’t it will show what’s not meeting the code. You can see the relevant code here: Part D3 Construction of Exits (see section D3D14 “Goings and Risers”) and Table D3D14 which specifies riser and going limits. (Note: I have increased the minimum going by 10mm, to 260mm)

These standards are usually used for public access and fire escapes, so may not apply if you are doing landscaping or surrounds at private residential properties. Check with designers and local authorities before building.

You should always confirm design sizes before building and do not rely on this tool as an authority. The NCC is the Australian authority at time of writing.

Riser “Layback”

This tool doesn’t consider any riser face “layback”. It calculates and depicts stairs like they are built with plumb riser faces.

Generally, riser layback can be achieved by either:

1. leaning the top of each riser out, or
2. leaning the bottom of each riser in

by an equal distance on each riser.

If you lean the bottom of each riser inward, I find it is smarter to allow for this when you are setting out the top and bottom throat points (the start and finish points of the stair flight) otherwise the shift in the bottom of the riser form encroaches on the throat’s thickness.

If you lean the top of each riser outward, ensure that the top-most going’s overall size is not affected by this – especially if the stairs must meet strict regulations.