Deck Footing Cost Guide: Bags, Tubes & Quotes

Deck footing cost starts with hole count, diameter, depth, and the type of footing under each post. The concrete amount is usually the smallest part of the decision. A real deck-footing quote can also include layout, digging, sonotubes or footing forms, post bases, rebar, inspection, access, spoil handling, cleanup, and return trips.

Use the Concrete Form Tube Calculator when the deck uses round Sonotube-style tubes or round pier forms. Use the Concrete Post Hole Calculator when a wood or steel post sits inside the hole and concrete fills the ring around it. Use the Concrete Footing Calculator when the plan calls for a continuous rectangular footing or grade beam. For bid comparison, use the Deck Footing Contractor Quote Checklist and the Concrete Quote Reviewer. If you searched for a shape-first concrete calculator for deck footings, use the Concrete Calculator for Deck Footings to choose between tubes, post holes, continuous footings, and larger piers before pricing the job.

Quick answer

Ten 12 inch diameter deck footing holes that are 36 inches deep need about 0.96 yd3 of concrete with 10% waste, or about 44 common 80 lb bags. That is the concrete material line only. It does not include layout, digging, tubes, post-base hardware, inspection, rebar, difficult soil, access, cleanup, or contractor labor.

Use approved local dimensions. This page helps estimate material and quote scope; it is not a deck design, frost-depth, bearing-capacity, permit, or code approval.

Pick the right footing calculator first

A deck footing page can go wrong when every round hole, tube, pier, and continuous footing is treated as the same shape. Before pricing the job, match the calculator to the actual footing detail on the plan.

If the quote does not say which footing type is included, ask before comparing prices. A bid for ten hand-dug tube footings is not the same scope as a bid for larger drilled piers, bell bottoms, or a continuous footing under a beam.

Deck footing formula

For one round footing hole or tube:

cubic feet = 3.1416 x radius ft x radius ft x depth ft
cubic yards = cubic feet / 27
order quantity = cubic yards x hole count x waste factor

A 12 inch tube has a 0.5 ft radius. If it is 48 inches deep, one tube is:

3.1416 x 0.5 x 0.5 x 4 ft = 3.14 ft3
3.14 ft3 / 27 = 0.116 yd3 before waste
0.116 yd3 x 1.10 = 0.128 yd3 with 10% waste

Six of those tubes are about 0.77 yd3 with waste, or about 35 common 80 lb bags if each bag yields about 0.6 ft3. If the holes are wider than the tube, the extra void can take more concrete than the tube math shows.

Material-only cost versus installed cost

Concrete material is only one line in a deck-footing estimate. A small deck may use less than one cubic yard of concrete, but the installed price can still be driven by layout, digging, forms, hardware, inspection, and access.

When a contractor quotes by hole, ask what is inside that hole price. A useful deck-footing quote should identify the footing count, diameter, depth, forming method, concrete method, hardware responsibility, inspection responsibility, and exclusions.

Bags or ready-mix?

Many deck footing jobs are bag-friendly because holes are scattered around a yard and the total quantity can be less than a full ready-mix minimum. Bags can also make sense when access is tight and a truck chute cannot reach the holes. The tradeoff is labor, water consistency, mixer pace, and keeping posts or anchors aligned before the concrete stiffens.

Ready-mix starts to deserve a quote when the deck has many deep footings, large 16 inch or 24 inch tubes, easy access, or a contractor crew ready to place all holes quickly. The delivered price can still be distorted by minimum billable yards, short-load fees, delivery charges, wait time, and washout. Check the same usable volume in the Ready-Mix vs Bags Calculator before deciding.

What changes the footing cost fast

Small footing changes compound quickly. Diameter grows with radius squared, so moving from a 12 inch hole to a 16 inch hole is not a one-third concrete increase. Deeper frost lines, over-dug holes, bell bottoms, or wider footing forms can also push a deck from a bag job into a ready-mix comparison.

Do not hide major overdig inside a normal waste factor. If several holes are larger than planned, remeasure before ordering concrete.

Quote checklist before approving work

Use this list before you accept a deck-footing quote:

If two bids use different footing counts, depths, or hardware assumptions, do not compare the totals until the scope is normalized. Send each bid through the Concrete Quote Reviewer with the same hole count, diameter, depth, concrete method, and inspection responsibility.

Source checks

Use public calculators and manufacturer guidance as a starting point, then verify your local plan requirements before ordering. The Decks.com concrete calculator shows why deck footing shape matters before material math. The QUIKRETE concrete calculator and Sakrete calculators help cross-check bag-yield assumptions. The Sonotube Builders Tube product page is useful for tube vocabulary and use cases. Ready-mix orders should still be confirmed with the supplier, especially when minimum loads, short loads, delivery windows, and access are involved.

FAQ

How many bags for deck footings?

It depends on hole diameter, depth, and count. Ten 12 inch by 36 inch holes need about 44 common 80 lb bags with 10% waste. Six 12 inch by 48 inch round tubes need about 35 common 80 lb bags.

Is deck footing concrete priced by hole?

Sometimes. A by-hole quote still needs a written scope for layout, digging, tubes or forms, rebar, concrete, post bases, inspection, access, cleanup, and exclusions.

Are Sonotubes and post holes the same calculation?

Not always. A filled tube is a full cylinder. A post hole with a post inside it is an annular fill because the post displaces part of the concrete.

When should I use ready-mix for deck footings?

Check ready-mix when the total bag count is high, the holes are ready at the same time, and access is good. Compare the delivered total after minimum billable yards, delivery, short-load fees, wait time, and washout.

Can I pour deck footings without inspection?

Permits and inspection requirements vary by location and deck design. Confirm the approved footing size, depth, reinforcement, hardware, and inspection timing before concrete is placed.

Next step

Choose the footing type first. For round deck tubes, run the Concrete Form Tube Calculator. For post-in-hole work, use the Concrete Post Hole Calculator. For continuous beam footings, use the Concrete Footing Calculator. Then compare the written scope in the Concrete Quote Reviewer.