Construction & Materials
Deck Footing Calculator
Use this deck footing calculator for early material planning before a structural plan decides exact pier size, spacing, depth, and placement.
Add extra material for cuts, damage, compaction, pattern matching, or field-measurement variation.
Use a local or package price if you want a rough material-cost estimate.
Concrete bags
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- Footings along length
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- Footings across width
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- Footing count
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- Concrete per footing
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- Concrete with waste
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- Cubic yards
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- Concrete bags
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- Waste / overage
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- Estimated material cost
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Study path
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What the deck footing calculator solves
Use this deck footing calculator for early material planning before a structural plan decides exact pier size, spacing, depth, and placement.
Formula
How to use it
- Enter the project dimensions using one consistent unit system.
- Enter the coverage, yield, package size, or spacing assumptions printed on the material or plan.
- Review the raw quantity, waste-adjusted quantity, rounded purchase quantity, and any cost estimate before ordering.
How to read the answer
The footing count is a simple grid estimate, and the concrete bag count rounds up after waste for early material planning.
Common mistakes and edge cases
- Do not treat the spacing as a structural design.
- Actual decks may use beams, ledgers, piers, and loads that change footing layout.
- Frost depth, soil, permits, and inspections can change footing depth and diameter.
Worked examples
Small freestanding deck
Concrete bags
52 bags
Wider footing grid
Concrete bags
140 bags
Frequently asked questions
Does this decide my deck footing spacing?+
No. It estimates material from a spacing you enter. Structural plans, loads, soil, frost depth, and local rules decide the actual layout.
Why does the calculator use a grid?+
A grid gives a conservative early planning count for freestanding rectangular decks. Real layouts may need fewer, more, or differently placed footings.
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Last updated: May 15, 2026