Choosing between 12″, 16″, and 24″ o.c. affects stiffness, materials, and cost. Here’s how to decide.
Performance vs cost
- 12″ o.c.: stiffest deck surface, highest material cost
- 16″ o.c.: common balance for most builds
- 24″ o.c.: only for specific decking and spans
Cost comparison (example)
| Spacing | Approx. joists for 12×16 deck |
|---|---|
| 12″ | 17 |
| 16″ | 13 |
| 24″ | 9 |
Use the Deck Joist Spacing Calculator to estimate spacing and view span charts to validate your plan.
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Planning tool only. Results and charts on this site are simplified planning aids based on common assumptions. They are not a substitute for stamped engineering, permits, or inspections. Always confirm with local building officials and product manufacturers.
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