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Deck Footing Calculator

Deck Sq Ft

Beam Spacing (ft)

Post Spacing (ft)

Concrete Source

Add Reinforcement?

Waste Factor

Result

—footings

◆ LIVE 3D PREVIEW

Footing Size

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Concrete (bags)

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How to Calculate Deck Footing

Use this free deck footing calculator to get instant, accurate results for your construction project. Simply enter your measurements above and the calculator will automatically compute the result using industry-standard formulas.

Pro Tip: Always add 10-15% extra material to account for waste, cuts, and job-site conditions. This is standard practice recommended by experienced contractors.

Related Calculators

▸ Column Footing ▸ Composite Deck ▸ Composite Deck Cost ▸ Concrete Footing ▸ Concrete Footing Depth ▸ Concrete Pier Deck

💡 Pro Tips — Deck Footing

Always order 10% extra — concrete is cheaper than a second pour or a short load.
4" minimum for walkways, 6" for driveways and garages.
Ready-mix vs bags: Over 1 cubic yard (27 cu ft), a ready-mix truck is almost always cheaper and faster.
Cure time: Walk-on in 24-48hrs, drive on in 7 days, full strength at 28 days.
Temperature matters: Best pouring temp is 50-80°F. Below 40°F needs hot water mix and insulating blankets.

📊 Coverage Reference Table

Thickness	Sq Ft per Yard	80-lb Bags per 100 sqft
3"	108	~14
4"	81	~19
5"	65	~24
6"	54	~28
8"	40	~38

❓ Frequently Asked Questions

+How much does a yard of concrete cover?

One cubic yard covers 81 sq ft at 4" thick, 54 sq ft at 6" thick, or 27 sq ft at 12" thick. Always order 10% extra.

+How many 80-lb bags make a cubic yard?

Approximately 45 bags of 80-lb concrete. For 60-lb bags, you need about 60. For 40-lb bags, about 90.

+How long does concrete take to cure?

Walk-on strength in 24-48 hours. Park a car after 7 days. Full structural strength at 28 days. Keep wet for the first 7 days for best results.

+Should I use rebar or wire mesh?

Wire mesh works for standard 4" patios. Use #4 rebar at 18" spacing for driveways, garages, or anything carrying vehicle weight.