Baluster calculator
Lay out equal clear gaps between two posts.
Formula
n = max(0, ceil((opening − limit)/(width + limit))); gap = (opening − n × width)/(n+1)
Clear opening: 6 ft · Baluster width: 1.5 in · Chosen maximum clear gap: 3.5 in · Balusters ≈ max(0,ceil((((6 ft × 0.3048 m/ft)-(3.5 in × 0.0254 m/in)-(8.881784197 × 10⁻¹⁶)×((6 ft × 0.3048 m/ft)+(3.5 in × 0.0254 m/in)))÷((1.5 in × 0.0254 m/in)+(3.5 in × 0.0254 m/in)))×(1-(8.881784197 × 10⁻¹⁶)))) · Equal clear gap ≈ max(0,(1.2954))÷((14)+1)×1000+0×(1.138156404)
How to use
- Measure the clear level opening.
- Enter actual baluster width and your gap limit.
- Read count and equal clear gap.
Examples
- A 1 m opening with 5 cm balusters and 10 cm gaps needs 6 balusters.
Frequently asked questions
Is the gap limit a building rule?
No. Choose it from the applicable design. This tool does not certify railing safety.
Are the end gaps equal?
Yes. There are n + 1 equal spaces around n balusters.
What if the pieces cannot fit?
A negative clear gap is rejected. Stairs, tapered shapes and post strength are outside this model.
Sources
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