Stair Calculator To Work Out Run and Rise Lengths, Free Online Tool

Private Stairs

Min Rise (mm) = 150 mm
Max Rise (mm) = 220 mm
Min Going (mm) = 220 mm
Max Going (mm) = 300 mm

Utility Stairs

Min Rise (mm) = 150 mm
Max Rise (mm) = 190 mm
Min Going (mm) = 250 mm
Max Going (mm) = 400 mm

General Access Stairs

Min Rise (mm) = 150 mm
Max Rise (mm) = 170 mm
Min Going (mm) = 250 mm
Max Going (mm) = 400 mm

Max Elevation Angle = 42º

Other Requirements:

• For school buildings, the preferred rise is 150 mm and the preferred going is 280 mm.
• For dwellings, for external tapered stairs that are part of the buildings, the going should be a minimum of 280 mm.
• For existing buildings, alternatives may be proposed if the dimensional constraints do not allow these requirements to be followed.
• There are more complex requirements for stepped gangways in assembly buildings, and there may be a conflict between these requirements and sightlines in some buildings with spectator seating.
• Buildings that are not dwellings and common areas in buildings that contain flats should not have an open riser, should have visual contrast to make nosings apparent, and nosings should not protrude by more than 25 mm.
• The minimum headroom should be 2 m.