Staircase calculator
Enter the height between floors and your preferred riser and tread to plan a straight flight of steps.
A planning aid for a straight flight. Have your architect check the design against the building rules.
How this is worked out
- Number of steps = floor height divided by the preferred riser, rounded up.
- Exact riser = floor height divided by the number of steps.
- Horizontal run = the tread depth times one less than the number of steps, because the top step meets the upper floor.
- Landings, headroom and the width of the stair are not included.
What it works out
A staircase is a set of equal steps. Each step has a riser (the height of the step) and a tread (its depth). The calculator divides the floor-to-floor height by your preferred riser, rounds to whole steps and gives the exact riser and the horizontal length the flight needs.
How to use it
- Enter the height from finished floor to finished floor.
- Enter the riser you would like, usually 6 to 7 inches.
- Enter the tread depth, usually 10 inches or more.
- Read the number of steps and the run, and check the run fits the space.
A worked example
A floor height of 10.5 feet (126 inches) with a 6.5 inch riser gives 20 steps of 6.3 inches. With a 10 inch tread the flight runs 15.8 feet along the floor.
Comfort and safety
The National Building Code is commonly cited for houses: a riser of no more than 190 mm (7.5 in) and a tread of at least 250 mm (10 in). Steps in one flight should be equal. Your architect will also plan landings, headroom and the width.
Questions about this tool
The riser is the vertical height of one step. The tread is the depth you put your foot on.
People adjust to a steady rhythm; one step of a different height is a common cause of falls.
No. A turn or landing adds length; ask your architect to plan it.
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