Baluster Gap & Spacing Calc

Calculate baluster spacing and materials for deck and stair railings — code compliant, built for builders.

Guessing at baluster spacing wastes material and risks failing inspection. The 4-inch sphere rule sounds simple, but getting even gaps across an odd-length span requires math. This app does it instantly.

Enter total span between posts, baluster width, post width, and max allowed gap (IRC 4-inch residential or IBC 6-inch commercial preset). Get the exact number of balusters, actual gap size, on-center spacing, and instant code pass/fail check.

Supports deck railings, stair railings, fence sections, and porch guards. IRC R312.1 and IBC compliant gap limits built in. Shows full layout summary with post-to-baluster spacing.

KEY FEATURES:

• IRC and IBC gap presets
• Even spacing calculation
• Code compliance check
• Works completely offline
• No account or login required

Built for deck builders, carpenters, general contractors, and home inspectors.