What is the standard maximum spacing?
Most building codes (like IRC) require that a 4-inch sphere cannot pass through the balusters, so spacing is typically set to a maximum of 4 inches.
Calculator
Enter your values
Results
Balusters Needed
22
Exact Spacing
3.7826"
Center-to-Center
5.2826"
Layout Plan
Installation guide
Start Point
To center the layout, find the center of the rail. Place the center of the middle space at the center of the rail.
Code Compliance
Your spacing of 3.7826" is within the maximum limit.
How to Use
Step-by-step instructions
- 1Enter the total length of the rail section.
- 2Enter the width of a single baluster.
- 3Enter the maximum allowed spacing (usually 4 inches).
- 4The calculator will provide the number of balusters and exact spacing.
Uniform Spacing
Determines the exact gap between balusters to ensure they are evenly distributed and meet code requirements (usually max 4 inches).
Spacing = (Length - (Count × Width)) / (Count + 1)Variables:
LengthTotal rail lengthWidthWidth of one balusterCountNumber of balustersExample
10ft Railing
Inputs:
Length:120 in
Width:1.5 in
Max Space:4 in
Steps:
- 1.Min Spaces = (120 + 1.5) / (4 + 1.5) = 22.09 -> 23 spaces
- 2.Balusters = 23 - 1 = 22
- 3.Spacing = (120 - (22 × 1.5)) / 23 = 3.78 inches
Result:
22 balusters, 3.78" spacing