Deck Baluster Calculator
Enter your clear span, baluster width, and desired maximum gap to get an even count and the actual resulting gap.
The open distance the balusters need to fill.
Identical, independent sections — not connected runs sharing a post.
Total balusters
9
- Balusters per section
- 9
- Actual gap
- 3.45 in
›Calculation details
The calculator finds the fewest balusters that keep every gap at or under your desired maximum, then spreads the leftover space evenly — including the two end gaps — across that many balusters. If the span is too short for that many balusters to physically fit, there's no valid layout at these dimensions.
How it works
This finds the smallest number of balusters that keeps every gap at or under the maximum you set, then spaces them — plus the two end gaps — evenly across the full span. If your span is too narrow for even the minimum count to physically fit at that width, the calculator says so directly instead of returning a number that wouldn't actually work.
FAQ
What maximum gap should I enter?
That depends entirely on your local building code — this calculator only does the spacing math once you tell it the limit. Check with your local building authority before finalizing a gap.
It says no valid layout exists — what now?
Your span is too short for balusters that wide to fit at all, even edge to edge with no gap. Use narrower balusters or work with a wider span.