Baluster Spacing Calculator

Lay out horizontal balusters with balanced end gaps and clear tape-measure marks.

Enter the clear opening—or a reference span with left and right offsets—plus the actual baluster width. Choose a baluster count or enter your own maximum clear gap. The calculator shows the balanced clear gap, on-center spacing, full left/center/right mark table, visual rail diagram, and a far-end check.

Imperial input accepts decimals, fractions, mixed numbers, and feet-and-inches. Metric entry is also supported. Calculations use exact rational arithmetic and round only for display.

Free features include unlimited calculations, count and maximum-gap modes, complete mark tables, diagrams, copy/share text, offline use, and three reopenable recent calculations. There are no ads and no account is required.

The optional one-time Pro upgrade adds named layouts with notes, reusable templates, advanced precision, nearby-count comparison, PDF field sheets, and JSON backup and restore. It is not a subscription.

Your layout data stays local to the device. The app has no advertising SDK and no analytics SDK.

Planning aid only. Verify local requirements, product instructions, permits, and inspection requirements before construction. The app does not determine code compliance or structural suitability.