Baluster Spacing Calculator

Use this calculator to space spindles between two posts. Enter the clear run, the baluster width, and the target gap (often 100 mm or 4 in max in many codes).

Spaces = max(1, floor((run + gap) ÷ (width + gap))). Count = spaces − 1. Actual gap = (run − count × width) ÷ spaces when count > 0. Run can be entered in metres (m) or feet (ft). Baluster width, target gap, and actual gap can be entered or shown in millimetres (mm) or inches (in).

This is a layout between posts. It does not check a specific building code, and it is not a stair-rake layout.

Run: Clear distance between posts, in m or ft.

Baluster width: Face width of one spindle, in mm or in.

Target gap: Desired clear gap, in mm or in.

Count: Number of balusters.

Spaces: Number of gaps, one more than the count.

Actual gap: Equalised gap that fills the run.