Sonotube Concrete Cost Guide 2026

Sonotube concrete cost starts with tube diameter and depth, then changes with hole count, waste, post bases, inspection, access, and whether the job is bagged concrete or ready-mix. A tube estimate should be separated from deck, porch, fence, sign, or pier labor.

Use the Concrete Post Hole Calculator for round tube volume and the How Many Bags of Concrete for a Post Hole? guide for a direct bag-count answer.

Tube diameter and depth deserve their own cost check because one small change can move the job from a few bags to a ready-mix minimum. Keep tube volume, inspection, hardware, access, and cleanup as separate quote lines.

Quick answer

A 12 inch diameter sonotube that is 48 inches deep needs about 0.13 yd3 with 10% waste, or about 6 common 80 lb bags. A 16 inch diameter tube at the same depth needs about 0.23 yd3 with waste, or about 11 common 80 lb bags.

Use approved local dimensions. Tube diameter and depth can be set by load, frost, soil, and code.

Formula

cubic feet = 3.1416 x radius ft x radius ft x depth ft
cubic yards = cubic feet / 27
order quantity = cubic yards x 1.10

For multiple tubes:

total yards = yards per tube x number of tubes

If holes are over-dug wider than the tube, estimate the actual hole or the void around the tube separately.

Cost and scope checklist

For deck-specific scope, read the Deck Footing Cost Guide.

Bags or ready-mix?

One or two tubes are usually bag-friendly. Many large tubes can quickly turn into a ready-mix comparison, but ready-mix minimums may make small tube jobs expensive. Use the Ready-Mix vs Bags Calculator when total bag count climbs.

Cost scenarios to price separately

A sonotube job can look tiny in cubic yards and still become expensive when the site has layout, access, or inspection work. Price these scenarios separately before you compare bids.

Keep the concrete material line separate from digging and hardware. A quote that says "sonotube install" can include only the pour, or it can include layout, excavation, tube cutting, rebar cages, anchor bolts, bracing, inspection, and site cleanup.

When the estimate changes fast

Small diameter changes compound because the tube is round. Moving from a 12 in tube to a 16 in tube is not a one-third increase in concrete. The cross-section area grows with radius squared, so the bag count can nearly double on deeper holes. Depth changes also matter when a local frost line pushes the bottom of the hole lower than the first sketch.

Before ordering, write down the approved diameter, actual depth, number of tubes, expected waste, and whether the hole is wider than the cardboard form. If the hole is over-dug, the extra void can take more concrete than the tube math shows. That extra concrete may be acceptable, but it should be planned rather than discovered when the last bag is empty.

Ready-mix call script

For a group of tubes, ask the supplier or contractor this before dispatch:

I have ___ tubes at ___ inch diameter and ___ inch depth. The calculated volume
with waste is ___ yd3. What is the delivered total after minimum yards, delivery,
short-load fees, wait time, and washout? Can the chute reach the holes, or should
I plan wheelbarrow, buggy, pump, or bag mixing?

If the answer is unclear, keep bags as the backup path and confirm whether the crew can mix and place fast enough to keep posts aligned before concrete starts setting.

Final quote check

Before the crew buys material, compare the estimate against the written scope. A useful sonotube quote should identify who marks the hole locations, who calls for utility locate where required, who digs and disposes of spoils, who supplies forms, who sets rebar or anchors, and who keeps posts or templates aligned while the concrete is placed. If inspection is required, confirm whether the inspection happens before concrete arrives and whether a failed inspection creates a reschedule or standby cost.

For DIY work, also check water access, mixing surface, bracing, and extra bags. For contractor work, ask whether the price includes layout, digging, concrete, hardware, cleanup, and return visits. That makes a small tube job easier to compare without hiding the real labor behind a low material number.

Material buffer note

Keep a small buffer for sloughed hole edges, uneven bottoms, and tube trimming, but do not hide a major overdig problem inside normal waste. If several holes are larger than planned, remeasure before buying so the order reflects the actual void the concrete will fill.

FAQ

How many bags for a 12 inch sonotube?

At 48 inches deep, plan about 6 common 80 lb bags with 10% waste.

How many bags for a 16 inch sonotube?

At 48 inches deep, plan about 11 common 80 lb bags with 10% waste.

Does tube cost include digging?

Only if the quote says so. Concrete material is separate from layout, digging, tubes, inspection, hardware, and cleanup.

Next step

Enter tube count, diameter, and depth in the Concrete Post Hole Calculator, then compare the full scope in the Concrete Quote Reviewer.