Estimate deck post spacing, number of posts, beam spans, tributary deck area, post reactions, footing load, beam line load, and deck support layout. Use this deck post spacing calculator for residential decks, porch decks, beam-supported decks, post layout planning, and preliminary structural estimating.
Post count:
The calculator divides usable beam length by target spacing, then adds end posts to estimate posts per row.
Actual spacing:
The calculator spreads beam spans evenly between posts after subtracting any end setbacks.
Post load:
The calculator estimates the load on a typical interior post from tributary depth, post spacing, deck load, beam self weight, and extra point load.
Footing check:
The calculator divides post load by footing area to estimate soil pressure.
A deck post spacing calculator helps estimate a practical post layout before sizing beams, posts, and footings.
It can help compare post count, beam span, tributary depth, deck load, post reaction, footing pressure, and approximate support layout.
Your result shows estimated usable beam length, beam spans, posts per row, total posts, actual post spacing, tributary depth, beam line load, typical interior post load, end post load, footing area, footing pressure, and simplified utilization checks. These are planning estimates only.
Deck post spacing depends on beam size, deck load, joist span, lumber species, footing capacity, and local code. Many layouts use spacing such as 6 to 8 feet, but the correct spacing must be verified with approved beam span tables.
Yes. For a beam supported by posts, the distance between posts is the beam span for that section of beam.
Estimate the beam line load from deck load and tributary width, then multiply by the post spacing. Interior posts usually carry more load than end posts in a simplified evenly spaced layout.
No. Final deck post spacing should be checked with local code, approved beam span tables, post sizing, footing size, lateral bracing, ledger requirements, connection hardware, frost depth, and professional review when needed.