GRAND CALCULATE · BALUSTER LAYOUT
Free Railing & Baluster Spacing Calculator
Calculate the number of spindles or balusters required between railing posts and work out equal clear gaps. Designed for metal fabricators, railing installers, balustrade manufacturers and DIY projects.
Enter your measurements, choose your spacing requirements and calculate a practical layout using millimetres or inches.
IN THE WORKSHOP
How to measure for equal spindle spacing
- Measure between the inside faces of the two railing posts. If the posts are not yet set out, use the post spacing calculator to locate their centres first.
- Enter the width that one spindle or baluster takes up across the opening, then the largest clear gap permitted for your job.
- Select Calculate spacing. The result shows the minimum number of equal-width spindles that meets your gap limit, including an equal gap at each end.
Worked example: 12 balusters between two posts
Start with a 1,413.3 mm clear opening, 20 mm balusters and a 99 mm maximum gap. The calculator gives 12 balusters and 13 gaps. The balusters occupy 240 mm, leaving 1,173.3 mm to divide by 13. Each clear gap is about 90.254 mm.
For workshop marks, adjacent baluster centres are about 110.254 mm apart: one clear gap plus one baluster width. The first centre is different: measure one gap plus half the width from the inside face of the end post, about 100.254 mm here.
Railing and baluster spacing FAQs
Is a clear gap the same as on-centre spacing?
No. The clear gap is the empty space from one baluster face to the next. Centre-to-centre spacing, also called “on center” on US drawings, includes the width of one baluster when both are the same width. Enter the clear gap limit in the calculator.
Can I enter a baluster width in fractional inches?
Yes. Select inches and enter a tape fraction such as 1 1/2 or its decimal equivalent, 1.5. Display precision changes how the result is shown; the calculator uses the unrounded spacing to determine the spindle count.
What maximum gap should I use for a balustrade?
Check the building regulations or building code applicable at the installation site and the project specification. Enter the limit that applies to that job. The example value is not a recommended limit, and the calculator does not certify compliance.
Once you know the quantity, use the linear cut list calculator to plan cuts from stock using the finished spindle length.
Calculations run in this browser. Enter decimals without thousands separators. Display precision changes the labels, not the layout.
All Grand Calculate tools →See Railing spacing in the app
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