Formula
Footings per row = round run length ÷ maximum spacing up + 1. Total footings = footings per row × row count.
Deck Footing Calculator
Plan a regular footing grid and optionally estimate cylindrical concrete volume and bags.
How this deck footing estimate works
A regular grid is useful for early deck planning, especially when comparing framing options. Keep the layout estimate separate from the structural and frost-depth decisions.
Worked example
A 20 ft run at 6 ft maximum spacing has 4 spaces and 5 footings per row. Two rows produce 10 footings before any concrete calculation.
Before you buy
If you add a footing diameter and depth, use the result to compare bag yield or delivery quantities. Confirm excavation access and inspection requirements first.
Assumptions
Defaults are starting points. Replace coverage, density, package yield, spacing, and allowance values with the product or plan you are actually using.
Limitations
This is a planning/layout estimator only. Frost, soil, loads, beams, drainage, permits, and local structural requirements need separate review.