01
Measure the total rise first
Measure the exact floor-to-floor height at the spot the stair will sit — floors are rarely level, so measure on site rather than from a plan. Every other number in the layout is derived from this one.
How to lay out a stair
The four things worth getting right before you touch a saw.
02
Pick a riser count that divides evenly
Most residential codes want each riser between roughly 4″ and 7¾″. Try riser counts in that window until the total rise divides into a whole, even number with no odd leftover step.
03
Keep tread depth and riser height in balance
A comfortable stair usually keeps riser height plus tread depth close to 17–18 inches. Tall risers want shallower treads; shallow risers can carry a deeper tread.
04
Check headroom and landing space
Once the run is set, confirm there's enough headroom the whole way up the stair, and that the landing at top and bottom gives enough clearance for a door swing or turn.