Layout model and usable dimensions
A tidy baluster layout shares the available space across the gaps at both ends and between every baluster. Enter the clear distance between the boundary posts, actual baluster width, and your selected maximum clear opening. The calculator finds the smallest baluster count that keeps all equal gaps within that limit and reports the center-to-center pitch. This is a geometric layout aid only. The allowed opening, guard height, member strength, fastening, and stair-specific requirements must be checked against the applicable rules and the railing system before installation.
Fit, direction and offcut constraints
- This straight horizontal layout does not model sloped stair rails or triangular openings.
- Some rules test the passage of a sphere rather than a single flat dimension. Geometry alone does not establish compliance.
- Round physical marks conservatively and recheck openings after fastening because installation tolerances can enlarge gaps.
Layout arithmetic and example
A worked example
A 72 in opening, 1.5 in balusters, and a selected 3.75 in maximum gap require 13 balusters. All 14 clear gaps are 3.75 in; the pitch is 5.25 in.
Measure and compare a layout
- Measure the clear opening between the finished boundary posts.
- Enter the true baluster width and a verified maximum gap.
- Mark the first center, then repeat the calculated pitch and check the far end.
Frequently asked questions
Does the calculator include gaps beside the posts?
Yes. It makes the two end gaps equal to all internal gaps.
Is a calculated gap proof my railing meets code?
No. Opening limits are only one part of railing requirements, and local rules and system specifications vary.
What is the difference between clear gap and center spacing?
Center spacing includes one baluster width. Clear gap is the open distance between adjacent baluster edges.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.