Baluster Spacing Calculator
Plan deck spindle spacing from the railing run, baluster width, end margins, and maximum clear opening. The result distinguishes clear opening from center-to-center pitch.
Advanced margins and fixed-count mode
For multiple railing sections, calculate each section separately. Add extra balusters for cuts or damage in your material order.
Verify local rules. Building codes can measure openings differently and may vary by railing location. Confirm the permitted clear opening and measuring points before construction.
Clear opening formula
For n balusters and n + 1 equal gaps, clear gap = (run − n × baluster width) ÷ (n + 1). The planner finds the smallest integer n whose opening is no greater than the selected maximum, unless you enter a fixed count.
Worked example
For a 72-unit run, 1.5-unit balusters, and a 4-unit maximum opening, 15 balusters leave an approximately 3.66-unit clear opening. That is not the same as the center-to-center pitch.