Sonotube Concrete Calculator: Yards and Bags by Tube Size
Enter diameter, height and how many tubes to get cubic yards plus Quikrete 80 / 60 / 40 lb bag counts. Tables below cover common deck-pier sizes computed with the same cylinder function as our column calculator.
Quick answer
A 12 in × 4 ft Sonotube needs 0.128 yd³ with 10% waste (3.142 ft³ exact) — about 6 × 80 lb Quikrete bags (0.60 ft³ each), 8 × 60 lb, or 12 × 40 lb. Six of those piers for a deck total 0.768 yd³ / 35 × 80 lb bags.
Updated 2026-10-23 · Uses Calcs.concreteColumn from this site’s concrete column calculator. Bag yields from Quikrete Concrete Mix data sheets (same figures as our Quikrete calculator). For post holes around a wood post, see the concrete for fence posts guide instead of duplicating that math here.
How much concrete for my Sonotubes?
Diameter in inches, height in feet. Defaults: 12 in × 4 ft, 1 tube, 10% waste. Bag yields: 80 lb = 0.60 ft³, 60 lb = 0.45 ft³, 40 lb = 0.30 ft³.
Result
How do I use the Sonotube concrete calculator?
- Enter the cardboard form’s inside diameter in inches and the pour height in feet (not the buried depth alone if the tube sticks above grade).
- Set the number of identical tubes. Bags are computed from the combined volume so one rounding covers the whole order.
- Keep 5–10% waste unless you are topping off an almost-full form.
- Pick 80, 60 or 40 lb bags to match what the yard stocks; yields match Quikrete Concrete Mix sheets already cited on this site.
- Structural size and rebar still come from your plan — this page only sizes the concrete volume.
What formulas does the calculator use?
It runs the existing TrueToolCalc cylinder function, then divides volume by published Quikrete bag yields.
| Quantity | Formula | Source / assumption |
|---|---|---|
| Tube volume | π × (D_in ÷ 24)² × H_ft | Calcs.concreteColumn (same as concrete column calculator) |
| Cubic yards | ft³ ÷ 27; × (1 + waste) | Ready-mix order quantity |
| 80 lb bags | ceil(ft³ × (1 + waste) ÷ 0.60) | Quikrete Concrete Mix No. 1101: 0.60 ft³ per 80 lb bag |
| 60 lb bags | ceil(ft³ × (1 + waste) ÷ 0.45) | Quikrete Concrete Mix 60 lb yield on site Quikrete page |
| 40 lb bags | ceil(ft³ × (1 + waste) ÷ 0.30) | Quikrete Concrete Mix 40 lb yield on site Quikrete page |
| N tubes | N × single-tube ft³, then bags from the total | One ceil on the combined volume |
Sonotube concrete by diameter and height (tube-by-tube)
Each cell is one tube at 10% waste. A 12 in × 4 ft form is 0.128 yd³ / 6 × 80 lb bags; an 8 in × 4 ft form is 0.057 yd³ / 3 bags; a 24 in × 4 ft form jumps to 0.512 yd³ / 24 bags. All rows use Calcs.concreteColumn.
| Diameter | Height | Exact ft³ | Order yd³ | 80 lb | 60 lb | 40 lb |
|---|---|---|---|---|---|---|
| 8 in | 3 ft | 1.047 ft³ | 0.043 yd³ | 2 | 3 | 4 |
| 8 in | 4 ft | 1.396 ft³ | 0.057 yd³ | 3 | 4 | 6 |
| 8 in | 5 ft | 1.745 ft³ | 0.071 yd³ | 4 | 5 | 7 |
| 8 in | 6 ft | 2.094 ft³ | 0.085 yd³ | 4 | 6 | 8 |
| 8 in | 8 ft | 2.793 ft³ | 0.114 yd³ | 6 | 7 | 11 |
| 10 in | 3 ft | 1.636 ft³ | 0.067 yd³ | 3 | 4 | 6 |
| 10 in | 4 ft | 2.182 ft³ | 0.089 yd³ | 4 | 6 | 8 |
| 10 in | 5 ft | 2.727 ft³ | 0.111 yd³ | 5 | 7 | 10 |
| 10 in | 6 ft | 3.272 ft³ | 0.133 yd³ | 6 | 8 | 12 |
| 10 in | 8 ft | 4.363 ft³ | 0.178 yd³ | 8 | 11 | 16 |
| 12 in | 3 ft | 2.356 ft³ | 0.096 yd³ | 5 | 6 | 9 |
| 12 in | 4 ft | 3.142 ft³ | 0.128 yd³ | 6 | 8 | 12 |
| 12 in | 5 ft | 3.927 ft³ | 0.160 yd³ | 8 | 10 | 15 |
| 12 in | 6 ft | 4.712 ft³ | 0.192 yd³ | 9 | 12 | 18 |
| 12 in | 8 ft | 6.283 ft³ | 0.256 yd³ | 12 | 16 | 24 |
| 14 in | 3 ft | 3.207 ft³ | 0.131 yd³ | 6 | 8 | 12 |
| 14 in | 4 ft | 4.276 ft³ | 0.174 yd³ | 8 | 11 | 16 |
| 14 in | 5 ft | 5.345 ft³ | 0.218 yd³ | 10 | 14 | 20 |
| 14 in | 6 ft | 6.414 ft³ | 0.261 yd³ | 12 | 16 | 24 |
| 14 in | 8 ft | 8.552 ft³ | 0.348 yd³ | 16 | 21 | 32 |
| 16 in | 3 ft | 4.189 ft³ | 0.171 yd³ | 8 | 11 | 16 |
| 16 in | 4 ft | 5.585 ft³ | 0.228 yd³ | 11 | 14 | 21 |
| 16 in | 5 ft | 6.981 ft³ | 0.284 yd³ | 13 | 18 | 26 |
| 16 in | 6 ft | 8.378 ft³ | 0.341 yd³ | 16 | 21 | 31 |
| 16 in | 8 ft | 11.170 ft³ | 0.455 yd³ | 21 | 28 | 41 |
| 18 in | 3 ft | 5.301 ft³ | 0.216 yd³ | 10 | 13 | 20 |
| 18 in | 4 ft | 7.069 ft³ | 0.288 yd³ | 13 | 18 | 26 |
| 18 in | 5 ft | 8.836 ft³ | 0.360 yd³ | 17 | 22 | 33 |
| 18 in | 6 ft | 10.603 ft³ | 0.432 yd³ | 20 | 26 | 39 |
| 18 in | 8 ft | 14.137 ft³ | 0.576 yd³ | 26 | 35 | 52 |
| 20 in | 3 ft | 6.545 ft³ | 0.267 yd³ | 12 | 16 | 24 |
| 20 in | 4 ft | 8.727 ft³ | 0.356 yd³ | 16 | 22 | 32 |
| 20 in | 5 ft | 10.908 ft³ | 0.444 yd³ | 20 | 27 | 40 |
| 20 in | 6 ft | 13.090 ft³ | 0.533 yd³ | 24 | 32 | 48 |
| 20 in | 8 ft | 17.453 ft³ | 0.711 yd³ | 32 | 43 | 64 |
| 24 in | 3 ft | 9.425 ft³ | 0.384 yd³ | 18 | 24 | 35 |
| 24 in | 4 ft | 12.566 ft³ | 0.512 yd³ | 24 | 31 | 47 |
| 24 in | 5 ft | 15.708 ft³ | 0.640 yd³ | 29 | 39 | 58 |
| 24 in | 6 ft | 18.850 ft³ | 0.768 yd³ | 35 | 47 | 70 |
| 24 in | 8 ft | 25.133 ft³ | 1.024 yd³ | 47 | 62 | 93 |
Reading the table: doubling diameter multiplies volume by four (12 in → 24 in at 4 ft goes from 6 to 24 × 80 lb bags). Doubling height doubles volume (12 in × 3 ft = 5 bags; × 6 ft = 9 bags).
How does height change a 12-inch Sonotube order?
Each extra foot on a 12 in tube adds 0.785 ft³ (0.032 yd³ with 10% waste) — roughly 2 × 80 lb bag per foot before the ceil on short pours.
| Diameter | Height | Exact ft³ | Order yd³ | 80 lb | 60 lb | 40 lb |
|---|---|---|---|---|---|---|
| 12 in | 2 ft | 1.571 ft³ | 0.064 yd³ | 3 | 4 | 6 |
| 12 in | 3 ft | 2.356 ft³ | 0.096 yd³ | 5 | 6 | 9 |
| 12 in | 4 ft | 3.142 ft³ | 0.128 yd³ | 6 | 8 | 12 |
| 12 in | 5 ft | 3.927 ft³ | 0.160 yd³ | 8 | 10 | 15 |
| 12 in | 6 ft | 4.712 ft³ | 0.192 yd³ | 9 | 12 | 18 |
| 12 in | 8 ft | 6.283 ft³ | 0.256 yd³ | 12 | 16 | 24 |
| 12 in | 10 ft | 7.854 ft³ | 0.320 yd³ | 15 | 20 | 29 |
How does diameter change a 4-foot Sonotube order?
At a fixed 4 ft pour, moving from 10 in (4 × 80 lb) to 16 in (11 × 80 lb) more than doubles the bag count because area grows with the square of diameter.
| Diameter | Height | Exact ft³ | Order yd³ | 80 lb | 60 lb | 40 lb |
|---|---|---|---|---|---|---|
| 6 in | 4 ft | 0.785 ft³ | 0.032 yd³ | 2 | 2 | 3 |
| 8 in | 4 ft | 1.396 ft³ | 0.057 yd³ | 3 | 4 | 6 |
| 10 in | 4 ft | 2.182 ft³ | 0.089 yd³ | 4 | 6 | 8 |
| 12 in | 4 ft | 3.142 ft³ | 0.128 yd³ | 6 | 8 | 12 |
| 14 in | 4 ft | 4.276 ft³ | 0.174 yd³ | 8 | 11 | 16 |
| 16 in | 4 ft | 5.585 ft³ | 0.228 yd³ | 11 | 14 | 21 |
| 18 in | 4 ft | 7.069 ft³ | 0.288 yd³ | 13 | 18 | 26 |
| 20 in | 4 ft | 8.727 ft³ | 0.356 yd³ | 16 | 22 | 32 |
| 24 in | 4 ft | 12.566 ft³ | 0.512 yd³ | 24 | 31 | 47 |
| 30 in | 4 ft | 19.635 ft³ | 0.800 yd³ | 36 | 48 | 72 |
| 36 in | 4 ft | 28.274 ft³ | 1.152 yd³ | 52 | 70 | 104 |
Worked example: six 12-inch deck piers
A small deck on six 12 in × 4 ft Sonotubes needs 0.768 yd³ with 10% waste. Ordering bags from the combined volume (18.850 ft³) gives 35 × 80 lb bags — not 36, which would over-order because each tube’s ceil is applied six times.
| Step | Working | Result |
|---|---|---|
| One tube | π × (12÷24)² × 4 | 3.142 ft³ = 0.116 yd³ |
| One tube + 10% | 0.116 × 1.10 | 0.128 yd³ (6 × 80 lb if bought alone) |
| Six tubes exact | 6 × 3.142 | 18.850 ft³ = 0.698 yd³ |
| Six tubes + 10% | 0.698 × 1.10 | 0.768 yd³ |
| 80 lb bags (combined) | 18.850 × 1.10 ÷ 0.60 | 35 bags |
| 60 lb / 40 lb | same total ÷ 0.45 / 0.30 | 47 / 70 bags |
Result looks wrong? Check these
- Height typed in inches: the height field is feet (a 48 in bury is 4 ft).
- Bags look high vs a ready-mix quote: small pier jobs are often bag-only; ready-mix minimum loads can exceed the whole order.
- Fence posts mixed in: a hole around a 4×4 is not a full cylinder — use the fence-post concrete guide.
- N × per-tube bags ≠ combined bags: this calculator ceils once on the total volume so you do not buy an extra bag for every pier.
- Bell footing or flared base: approximate as a short wide cylinder plus the shaft, or add waste; the form is no longer a straight tube.
Sonotube pier or fence-post hole?
Sonotube (and generic cardboard concrete forms) are full cylinders you fill to make a pier or column. Fence-post concrete is usually an annulus: you dig a hole, set the post, and fill around it. This page covers the full-cylinder case only. Post spacing, hole diameter and bags-per-post live on the concrete for fence posts guide and the fence calculator — we do not copy those tables here.
Frequently asked questions
How much concrete for a 12-inch by 4-foot Sonotube?
A 12 in diameter × 4 ft Sonotube holds 3.142 ft³ (0.116 yd³). With 10% waste that is 0.128 yd³ — about 6 bags of 80 lb Quikrete Concrete Mix (0.60 ft³/bag), 8 of 60 lb (0.45 ft³), or 12 of 40 lb (0.30 ft³).
What formula does a Sonotube concrete calculator use?
Cylinder volume: V(ft³) = π × (diameter_in ÷ 24)² × height_ft, then yd³ = ft³ ÷ 27. This page calls Calcs.concreteColumn from the same formula as our concrete column calculator.
How many Quikrete bags for a Sonotube?
Divide the tube volume (with waste) by the bag yield on Quikrete's data sheet: 80 lb Concrete Mix No. 1101 yields 0.60 ft³, 60 lb yields 0.45 ft³, and 40 lb yields 0.30 ft³. A 12×4 tube at 10% waste needs 6 × 80 lb bags.
How much concrete for six 12-inch deck piers?
Six 12 in × 4 ft tubes total 18.850 ft³ (0.768 yd³ with 10% waste). Order bags from the combined volume: 35 × 80 lb, 47 × 60 lb, or 70 × 40 lb — fewer than six times the per-tube bag count because rounding is applied once.
Sonotube vs fence-post hole — which calculator?
Use this page for round cardboard forms (deck piers, columns). For post holes filled around a wood post, use the fence-post concrete guide instead — that job is an annulus, not a full cylinder.
Do I need rebar in a Sonotube pier?
Volume calculators do not design the pier. Diameter, depth below frost line, and reinforcement follow your local building code and the deck or house plan — ask the building department or an engineer.
Should I add waste when ordering for Sonotubes?
Yes. 5–10% covers bow in the tube, form leak, and chute cling. This calculator defaults to 10%; ready-mix minimum-load charges often matter more than waste on small pier jobs.
What Sonotube diameters are common for decks?
Deck piers commonly use 8, 10 or 12 in forms; larger tubes (16–24 in) show up under heavy posts or as short columns. Always match the diameter and bury depth on your approved plan.
Sources
- TrueToolCalc
Calcs.concreteColumnin js/calcs.js: V = π r² h with r = diameter_in / 24 (same function as concrete column calculator). - Quikrete, Concrete Mix No. 1101 data sheet: 80 lb bag yields 0.60 ft³ (retrieved 2026-10-15; cited on our Quikrete calculator).
- Quikrete bag yields for 60 lb (0.45 ft³) and 40 lb (0.30 ft³) Concrete Mix as listed on truetoolcalc.com/calculators/quikrete-concrete-calculator.html (fetched with the brand sheets, 2026-10-15/16).
- Sonotube / cardboard concrete forms are trade names for cylindrical pour forms; structural diameter, frost depth and reinforcement follow local code and the project plan — this page estimates volume only.
Related calculators & guides
- Concrete column / pier volume
- Bags of premixed concrete
- Quikrete bag yields
- Continuous footing volume
- Slab plus gravel base
- Concrete for fence posts (annulus / post-hole — not a Sonotube)
- Fence materials calculator
Last updated 2026-10-23 · About TrueToolCalc and how we check numbers · Found an error? Use the contact page.