Calculated result
Adjust the editable example, then select Calculate.
Method and assumptions
For N balusters of width B in opening W, remaining open space is W − N × B. Equal edge and internal gaps divide this by N + 1. Balusters at both edges divide it by N − 1 internal gaps. Maximum-gap mode finds the smallest whole count whose calculated gaps do not exceed the maximum you supply; no legal maximum is preset.
Worked example
A 60-inch clear opening with ten 1.5-inch balusters and equal edge gaps leaves 45 inches across eleven gaps: about 4.091 inches each. This is geometry, not a compliance finding.
Common mistake
Do not confuse clear gap with center-to-center spacing. Do not assume one gap limit applies to every guard, stair, jurisdiction, or project.
Planning limits
This calculator does not determine the applicable code, certify a railing, account for field tolerances or angled stairs, or assess load or connections. Verify project-specific requirements separately.
Privacy
Measurements and results stay in this browser tab. The calculator does not send input values, store them, or place them in the URL. No account or upload is required.
Quick question
Is there a built-in code-compliant gap?
No. If you use maximum-gap mode, enter a limit established for your own project and verify the completed layout with the applicable authority or professional.