Concrete Cylinder Calculator — Universal Round-Volume Math for Light-Pole Bases, Water-Tank Pads, Storage-Tank Footings & ASTM C39 Test Cylinders
Universal cylindrical-volume calculator returning cubic feet, cubic yards, cubic meters, liters, US gallons, and 80-lb / 60-lb bag count in one calc. Built for the use cases where a Sonotube product calculator falls short: light-pole bases, water tank foundations, storage-tank pads, ASTM C39 6×12 test cylinders, and any custom round-pour where you need SI and imperial volume units side-by-side.
Concrete Cylinder Calculator
Enter project dimensions below — results update instantly. Switch units freely.
Estimates assume typical industry density and waste factors. Always verify with your supplier and local building code before purchasing material.
Why Concrete Cylinder Calculator Estimates Go Wrong
Most round-concrete-volume calculators on the web are Sonotube calculators — tuned for the form-tube product line by Sonoco, with diameter defaults to 8 / 10 / 12 / 14 in (standard Sonotube sizes), depth in feet, and output in cubic yards + bag count for the typical deck-pier use case. That’s great for ~70% of round-pour projects. The other 30%, three cases come up regularly where Sonotube-shaped tools don’t fit cleanly:
- Non-standard diameters not in Sonotube’s product line — e.g. 36 in or 60 in pads for water tanks; 6 in for ASTM C39 test cylinders; 20 in for highway light-pole bases. The Sonotube product line tops out at 48 in; anything beyond, or anything between standard sizes (e.g. 22 in), needs a general cylindrical volume calc.
- SI units required (m, m³, L) — international projects, lab testing, sustainability reporting. Sonotube calcs are imperial-first; converting on the fly invites errors. This calculator returns ft³, yd³, m³, liters, and US gallons in one output so you don’t convert.
- Use cases that aren’t deck piers — water tank pads (where you also need to know the water-volume equivalent in gallons or liters), storage-tank footings (where you might compare concrete volume to tank capacity), ASTM C39 6×12 in test cylinders (where the volume math is ‘how much concrete to fill 10 cylinders for the cylinder break-test program’), solar mounting bases, light-pole pads, HVAC condenser pads. None of these are well-served by the Sonotube product framing.
For Sonotube-product-driven projects (deck piers, fence post footings, mailbox bases), use the dedicated Sonotube Calculator instead — it has the Sonotube-specific recommendations baked in. For everything else cylindrical, this calculator is the right tool.
How to Calculate Concrete Cylinder Calculator
The cylindrical-volume formula is the simplest in geometry — cross-section area × height — but the unit conversions trip people up. Here’s the math in both imperial and SI:
SI (single cylinder): Vm³ = π × (Dm ÷ 2)² × Hm
D = diameter; H = height (or depth). The 24 in the imperial divisor combines diameter-to-radius (÷2) and inch-to-foot (÷12) conversions in one step. SI form is cleaner because the units share the meter base.
Conversion factors used in the output panel:
- 1 ft³ = 0.0283168 m³ = 28.3168 liters = 7.48052 US gallons
- 1 yd³ = 27 ft³ = 0.764555 m³ = 764.555 liters = 201.974 US gallons
- 1 m³ = 35.3147 ft³ = 1,000 liters = 264.172 US gallons
- 80-lb concrete bag yield = 0.6 ft³ (typical Quikrete / Sakrete spec)
- 60-lb concrete bag yield = 0.45 ft³
| Diameter | Height | ft³ | yd³ | m³ | Liters | US gal | 80-lb bags |
|---|---|---|---|---|---|---|---|
| 6 in | 12 in (1 ft) | 0.196 | 0.007 | 0.0056 | 5.6 | 1.47 | 1 |
| 10 in | 4 ft | 2.182 | 0.081 | 0.0618 | 61.8 | 16.3 | 4 |
| 12 in | 4 ft | 3.142 | 0.116 | 0.0889 | 88.9 | 23.5 | 6 |
| 18 in | 6 ft | 10.603 | 0.393 | 0.300 | 300 | 79.3 | 18 |
| 24 in | 4 ft | 12.566 | 0.466 | 0.356 | 356 | 94.0 | 21 |
| 36 in | 1 ft | 7.069 | 0.262 | 0.200 | 200 | 52.9 | 12 |
| 48 in | 2 ft | 25.133 | 0.931 | 0.712 | 712 | 187.9 | 42 |
| 60 in | 1 ft | 19.635 | 0.727 | 0.556 | 556 | 146.9 | 33 |
Concrete Cylinder Coverage Table and Material Reference
| Application | Typical diameter | Typical depth / height | Bars per pour | Bag / Truck recommendation |
|---|---|---|---|---|
| Highway light-pole base | 24 in | 5 ft | 1 | Per project — multiple bases per truck |
| Solar mounting base (rural) | 20–24 in | 3–4 ft | ~4 vert #4 + spiral | Group 30+ bases per truck delivery |
| HVAC condenser pad (residential) | 36–48 in | 4–6 in | Optional #4 grid | 1–3 bases per project, bag pour |
| Water tank pad (1,000 gal residential) | 60 in | 8 in | #4 grid 12 in OC | Single pour, ready-mix |
| Storage tank footing (commercial) | 120–240 in | 12–18 in | Engineered design | Engineered, ready-mix |
| ASTM C39 test cylinder | 6 in | 12 in | None | Made from same mix being tested |
| Architectural columns (round) | 10–16 in | 8–16 ft | Per ACI 318 1% A g | See column calculator |
| Septic riser ring (cast in place) | 24–36 in | 6–18 in | Optional spiral | Single pour, bag |
| Mailbox / sign post footing | 10–14 in | 30–42 in | Optional 1 #4 anchor | 1–2 bags per post |
For projects on this list use the cylinder calculator above; for Sonotube-form deck-pier projects use the dedicated Sonotube Calculator; for above-grade structural columns use the Concrete Column Calculator (which includes ACI 318 rebar sizing).
| Diameter (in) | Cross-section (in²) | Volume (ft³) | Volume (yd³) | % of 12-in baseline |
|---|---|---|---|---|
| 6 | 28.3 | 0.79 | 0.029 | 25% |
| 8 | 50.3 | 1.40 | 0.052 | 44% |
| 10 | 78.5 | 2.18 | 0.081 | 69% |
| 12 | 113.1 | 3.14 | 0.116 | 100% (baseline) |
| 16 | 201.1 | 5.59 | 0.207 | 178% |
| 18 | 254.5 | 7.07 | 0.262 | 225% |
| 20 | 314.2 | 8.73 | 0.323 | 278% |
| 24 | 452.4 | 12.57 | 0.466 | 400% |
| 30 | 706.9 | 19.63 | 0.727 | 625% |
| 36 | 1017 | 28.27 | 1.047 | 900% |
| 48 | 1810 | 50.27 | 1.862 | 1,600% |
| 60 | 2827 | 78.54 | 2.909 | 2,500% |
Volume scales with diameter squared — doubling diameter quadruples volume, not doubles it. This is the single most common cylinder-pour estimating mistake: assuming a 24-in base needs only 2× the concrete of a 12-in base, when it actually needs 4×. Always compute, don’t scale linearly.
| Cylinder dims | Concrete weight (lb) | Water capacity (lb) | Water volume (US gal) | Notes |
|---|---|---|---|---|
| 24 in dia × 4 ft | 1,879 | 784 | 94 | Single light-pole base |
| 36 in dia × 4 ft | 4,228 | 1,764 | 211 | Residential water tank pad |
| 48 in dia × 4 ft | 7,517 | 3,135 | 376 | Large residential tank pad |
| 60 in dia × 4 ft | 11,745 | 4,898 | 587 | Small commercial tank base |
| 120 in dia × 1 ft | 11,745 | 4,898 | 587 | Wide shallow tank pad |
Concrete weight assumes 150 lb/ft³ (standard 4,000-PSI mix); water at 62.4 lb/ft³. The right-hand columns matter when sizing a slab that will support a water tank — the concrete weighs ~2.4× the water it can hold by volume. For seismic / load-bearing calcs, sum both (concrete dead load + water live load) when sizing the underlying subgrade or pile foundation.
Real-World Example Calculations
Worked Example 1: 32 Solar Mounting Bases (22 in dia × 3 ft, Non-Standard Diameter)
Rural Delaware ground-mount solar array, 32 cylindrical concrete bases at 22-in diameter × 3 ft deep. Augered holes, no Sonotube form. Single ready-mix truck delivery.
- Diameter
- 22 in (non-standard, between Sonotube 18 and 24)
- Depth
- 3 ft
- Count
- 32
- Waste
- 8% (open-hole pour, more spillage)
Takeaway: Comparing to rounding up to 24-in Sonotube: 24-in × 3 ft = 9.42 ft³/base × 32 × 1.08 = 326 ft³ = 12.07 yd³ (needs 2 trucks if > 11 yd³ single-axle cap) + $1,344 in Sonotube form cost = ~$3,500 total vs $1,768 with non-standard cylinder. Saving $1,544 on this project by computing the actual diameter rather than rounding to nearest Sonotube.
Worked Example 2: 10 ASTM C39 Test Cylinders (Cylinder Break-Test Program)
Commercial slab pour requires concrete strength verification per ACI 318. Make 10 standard ASTM C39 6×12 in cylinders from the in-place mix, cure 28 days, break-test for f′c verification.
- Diameter
- 6 in (ASTM C39 standard)
- Height
- 12 in (1 ft, ASTM C39 standard)
- Count
- 10
- Waste
- 10% (filling cylinders by hand, more spillage)
Takeaway: ASTM C39 cylinder testing is required for any structural concrete pour above the residential threshold. The 10-cylinder program (2 cylinders tested at each of 5 strength-gain intervals: 1, 3, 7, 14, 28 days) is the standard QC practice. Make cylinders from the in-place mix during pour — don’t mix a separate small batch for testing, the strength won’t match the placed concrete. The 2.16 ft³ cylinder material is part of the truck’s yield, not an extra order.
Worked Example 3: 60×8 in Water Tank Pad (Residential 1,000-gal Tank)
Residential water tank installation, 1,000-gal cylindrical fiberglass tank on a poured concrete pad 60-in diameter × 8 in thick over compacted aggregate base. Bag pour using #80 mix.
- Diameter
- 60 in (pad diameter, 12 in wider than 48-in tank to provide bearing)
- Thickness
- 8 in
- Count
- 1
- Waste
- 5%
Takeaway: Just under 1 yd³ — bag pour is the right choice (vs ready-mix $263 minimum + short-load fee). 23 × 80-lb bags is manageable with one mixer and 2 people in ~3 hours. Compare the concrete pad weight (1,879 lb dry) to the loaded tank weight (1,000 gal water = 8,345 lb + tank shell ~150 lb = 8,495 lb) — the pad provides a stable bearing surface but the underlying subgrade carries the load. Verify subgrade compaction to 95% Standard Proctor before placing pad.
Sources & Standards
These references are used for terminology, safety boundaries, and engineering assumptions. Local code, supplier specifications, and licensed design documents still control your project.
-
ASTM C39/C39M-23: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
ASTM International
Referenced for the standard test cylinder dimensions (6-in diameter × 12-in height) and the break-test program structure used in Worked Example 2.
-
ACI 318-19: Building Code Requirements for Structural Concrete
American Concrete Institute
Referenced for the structural-concrete strength verification program (f′c testing via cylinder break-tests, sampling frequency per ACI 318 §26.12).
-
NIST Reference on Constants, Units, and Uncertainty — Unit Conversions
National Institute of Standards and Technology
Referenced for the imperial-to-SI unit conversion factors used in the output (1 ft³ = 0.0283168 m³, etc.).
-
ASTM C94/C94M: Standard Specification for Ready-Mixed Concrete
ASTM International
Referenced for ready-mix delivery specifications relevant to single-cylinder and multi-cylinder pour projects.
-
PCA: Concrete Density & Yield Calculations
Portland Cement Association
Referenced for the 150 lb/ft³ concrete density (4,000 PSI mix) and the 80-lb bag yield (0.6 ft³) figures used in the conversion tables.
Frequently Asked Questions
How do I calculate concrete for a cylinder?
The formula is π × (diameter ÷ 2)² × height for any cylindrical pour, in consistent units. For imperial: V (ft³) = π × (D in ÷ 24)² × H ft — the 24 combines diameter-to-radius (÷2) and inch-to-foot (÷12) conversions. Then divide by 27 for cubic yards, by 0.6 for 80-lb bag count. The calculator above handles all the conversions and returns ft³, yd³, m³, liters, gallons, plus 80-lb and 60-lb bag counts in one calc.
What’s the difference between this cylinder calculator and the Sonotube calculator?
This calculator: universal cylindrical-volume math for any diameter, any height, in imperial OR SI units, with SI output (L, m³, gallons) for non-deck-pier use cases (water tank pads, light-pole bases, storage tank footings, ASTM C39 test cylinders). The Sonotube calculator: tuned for standard Sonotube product diameters (8 / 10 / 12 / 14 / 18 / 24 in) with deck-pier-specific recommendations (frost depth, footing pad sizing, bell-bottom math). Use Sonotube for deck piers and fence posts; use this for everything else cylindrical.
How much concrete for a 24-in diameter × 4-ft cylinder?
12.57 ft³ or 0.466 yd³ or 21 × 80-lb bags, no waste. With 5% waste: 22 bags or 0.49 yd³. This is the standard size for highway light-pole bases and small storage-tank footings. For multiple cylinders, multiply by count and add waste. Cross-check with the volume table above.
How does cylinder volume scale with diameter?
Cylinder volume scales with the square of the diameter (cross-section area = π × r²). Doubling the diameter quadruples the volume; tripling the diameter multiplies it by 9. A 24-in cylinder holds 4× the concrete of a 12-in cylinder of the same height — not 2×. This is the single most common cylinder-pour estimating mistake. Always compute from the formula or read off the lookup table; never scale linearly with diameter.
Can I use this calculator for ASTM C39 concrete cylinders?
Yes. ASTM C39 standard test cylinders are 6 in diameter × 12 in (1 ft) height = 0.196 ft³ (5.6 L / 1.47 US gal) per cylinder. Set diameter = 6 in, height = 12 in (or 1 ft), count = number of cylinders in your break-test program (typically 10 for full strength-gain coverage at 1, 3, 7, 14, 28 days). Total volume for 10 cylinders = 1.96 ft³; add waste for hand-filling (10%) for an order quantity of ~2.16 ft³. Skim from the in-place pour mix; don’t mix a separate batch.
Is concrete cylinder volume the same as cylinder water capacity?
Volumetrically: yes — a 24-in × 4-ft cylinder holds the same volume of concrete (12.57 ft³) as it would hold of water if it were a hollow tank. By weight: very different — concrete weighs ~150 lb/ft³ (4,000-PSI mix) vs water at 62.4 lb/ft³, so the same cylinder holds ~2.4× more weight in concrete than in water. The calculator outputs both for use cases where you need to compare concrete pour weight against water-tank live load (e.g. designing a slab to support a poured water tank).
How do I convert cylinder volume from cubic feet to cubic meters?
Multiply by 0.0283168. 1 ft³ = 0.0283168 m³; 1 yd³ = 0.764555 m³; 1 m³ = 35.3147 ft³. The calculator above does both conversions automatically — enter your input in imperial or SI (the diameter / height fields accept both unit systems), and the output panel shows ft³, yd³, m³, liters, and US gallons simultaneously. Useful for projects with mixed-unit contractor / supplier specs (most US contractor specs in ft³ or yd³; international supplier datasheets in m³ or liters).