Calculate perfectly equal spacing for deck spindles, balusters, or pickets while meeting safety codes.
Railing Specs
Layout Specifications
Enter measurements to calculate spacing
About this calculator
Overview
Spacing spindles (balusters) evenly is one of the more tedious parts of deck building. This calculator ensures all gaps are identical and that none exceed the maximum spacing allowed by building codes (typically 4 inches).
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Pro Tips
Measure the distance between the inside edges of your posts for the 'Railing Length'.
Cut a spacer block to your 'Actual Gap' dimension to make installation much faster and more accurate.
The 'On-Center Spacing' is the distance from the center of one spindle to the center of the next.
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Fun Facts
"Most US building codes require that a 4-inch ball cannot pass through any part of the railing."
"A standard 2x2 wood spindle is actually 1.5 inches by 1.5 inches."
"Equal spacing is not just about safety; it's what makes a railing look professionally installed."
Formula: Min Spindles = ceil((Length - MaxGap) / (Width + MaxGap))
Actual Gap = (Length - NumSpindles * Width) / (NumSpindles + 1)
