Railing Calculator
Calculate the number of balusters, posts, and rails needed for your railing project.
Enter length and baluster spacing.
Railing Materials
Railing material calculations:
Posts = (Total Length / Post Spacing) + 1
Balusters per Section = (Post Spacing / (Baluster Width + Baluster Spacing)) - 1
Total Balusters = Balusters per Section × Number of Sections
Top & Bottom Rails = 2 × Number of Sections
Building code notes:
- Maximum baluster spacing: 4 inches (10 cm) — a 4-inch sphere must not pass through
- Standard baluster width: 1.5 inches (3.8 cm)
- Standard post spacing: 6–8 feet (1.8–2.4 m)
- Minimum railing height: 36 inches (91 cm) for decks, 34 inches (86 cm) for stairs
Add 10% extra for waste and cuts.