Deck Railing Calculator
Estimate railing posts, balusters, and rails for your deck
Total linear feet of railing
Max 6 ft on center
Max 4" gap per code
Width of each baluster
Posts Needed
—
posts
Balusters Needed
—
balusters
Top Rail Length
—
ft
Estimated Cost
—
USD
How to Use This Calculator
Deck railing requires precise baluster calculations to meet building codes. Our calculator determines posts, balusters, and rails.
- Measure total railing length
- Determine post spacing
- Set baluster spacing (max 4" gap)
- Enter specifications
AI Insights
Smart analysis for your project
Smart Estimates
Our AI cross-references material costs, regional pricing, and project complexity for more accurate estimates.
Waste Optimization
AI-calculated waste factors based on project type, not flat percentages. Saves 5-15% on material costs.
Best Practices
Recommendations derived from building codes, contractor data, and thousands of completed projects.
Calculation Formula
Posts = (Length / Post spacing) + 1
Balusters = Length x 12 / (Baluster width + Spacing)
Top rail = Length
Frequently Asked Questions
What is maximum gap between deck balusters?
Building code requires a maximum 4-inch gap between balusters (4-inch sphere rule).
How high should deck railing be?
Residential deck railing must be at least 36 inches high. Required for decks > 30" above grade.