Rail Calculator

The lengths of each side of a deck often vary. As a result, the post spacings for a railing will vary as will the length of the railing section that fits between each post.

This tool will save you time and show you how far apart to set your balusters from each other and from each post so the balusters appear perfectly balanced in each of your railing sections.

For help, simply click on the(?) beside the section you need help with, Or watch this Tutorial Video.


Both fields are mandatory. The spacing between balusters cannot be larger than 4".

Width of Baluster:
Spacing Between Balusters:

Identify each side of your deck that requires a rail. Each side will be made up of one or more railing "Sections" that should be identically sized to give you a nice balanced appearance. For example, one side that is approximately 15' long may have three 5'railing sections.

Input the distance between the faces of opposing posts that is representative of that 5' railing "Section". The results you get apply to all railing "Sections" along that particular side of your deck.

If other sides of your deck have different sized "Sections" simply input the dimension for as many different railing "Sections" you may have.

Section A:
Section B:
Section C:

**Based on your selected baluster width (b), spacing (c) and distance between opposing post faces (a), the space between the posts and the first and last baluster has been calculated a displayed below (d).


Baluster Calculator