How to Use the Stair Handrail Height Checker
When building or remodeling a home, confirming your stair handrail meets code before an inspection can save you a costly rework later. Enter your handrail height and baluster spacing, and this checker instantly tells you whether they meet the standards commonly referenced in the U.S. International Residential Code (IRC) and International Building Code (IBC).
Handrail height is measured vertically from the leading edge (nosing) of the stair tread to the top of the handrail. The IRC generally requires this height to fall between 34 and 38 inches. Too low and the rail doesn't support your full weight well; too high and it becomes hard to grip in a stumble.
Baluster (guard) spacing refers to the gap between adjacent vertical rail members. Code requires this opening to be small enough that a 4-inch diameter sphere cannot pass through — the so-called "4-inch sphere rule" — which prevents a young child's head or body from slipping through and falling. Measure both values with a tape measure, and if either fails, consider adding blocking or replacing the rail assembly before your next inspection.
Frequently Asked Questions
Measure vertically from the leading edge (nosing) of the stair tread to the top surface of the handrail.
Under IRC/IBC guard requirements, openings between balusters must not allow a 4-inch diameter sphere to pass through, preventing young children from slipping through or getting their head stuck.