Calculate deck joist spacing from a few simple inputs generally.
Deck Joist Spacing — figures are approximate reference values; verify current rates and rules with the official source before relying on them.
Formula
Joists = floor(length × 12 ÷ spacing) + 1 + extras
Reference estimate — verify with the official source.
No — it is a reference estimate. Confirm rates, limits and rules with the official source.
Rates are approximate reference values. Local rates, exemptions and rules can differ, so treat the output as a planning figure only.