Railing Calculator

How much railing do I need?

ft
ft
posts
in
Rail stock

Order this much balusters

65balusters

Posts at 6 ft with a 3.5 in target gap so a 4 in sphere cannot pass. Guards 30 in above grade generally need a 36 in height. Confirm with local code and your railing's manufacturer.

6 ft sections, 13 balusters each30 ft, 5 sections, orange = corners
Posts8
Top and bottom rail8 × 8 ft
Balusters per section13
Clear gap3.5 in

Count posts, top and bottom rail and balusters for a whole run. Corners and post spacing change the post count quickly.

How it works

Sections come from run length ÷ post spacing. Each section gets an even baluster layout at about 3.5 inches clear.

Before you order

  • Many post-to-framing connections are what fail, so use the connector the plans specify.
  • Keep rail joints centered on posts.
  • Guard height is usually 36 inches for decks over 30 inches above grade, and local code may ask for more.

Common questions

How far apart can railing posts be?

Six feet is a common maximum for wood guards, and products with their own tested systems may differ.

How high must a deck railing be?

Under the common residential code, at least 36 inches where the deck is more than 30 inches above grade. Local rules can be stricter.