Cylinder Cubic Yardage Calculator

A cylinder cubic yardage calculator returns the concrete needed for round footing or pier forms, in cubic yards. It multiplies each form's area by its depth and the number of forms, adds the waste allowance (10% by default), and divides by 27. Four 12 in. piers, 4 ft deep, need about 0.51 cubic yards.

Last reviewed September 2026Method & sources Report an error

Not to scale.

Concrete Needed (with waste)

0.512 cu yd

Includes a 10% waste allowance.

Breakdown
Concrete Needed (with waste)	0.512 cu yd
Raw Volume	12.6 cu ft

How to Calculate Cylinder Cubic Yardage

Each round form's volume is π × radius² × depth (from its diameter and depth). Multiplying by the number of piers or footings gives total raw volume. NRMCA's CIP 31 guidance to order 4-10% extra ready-mix concrete (the same figure the Concrete Slab and Concrete Footing calculators use) is added to cover minor form variance. Then the total converts to cubic yards.

Example: 4 piers, 12 in. diameter forms, 4 ft deep, 10% waste

4 piers, 12 in. diameter forms, 4 ft deep, 10% waste: 1. Cross-sectional area: π × (12 ÷ 12 ÷ 2)² = π × 0.25 = 0.785 sq ft 2. Volume per pier: 0.785 × 4 = 3.14 cu ft 3. Total raw volume: 3.14 × 4 = 12.57 cu ft 4. With 10% waste: 12.57 × 1.10 = 13.82 cu ft 5. Cubic yards: 13.82 ÷ 27 = 0.512 cu yd

Cylinder Cubic Yardage: Compare Scenarios

Scenario	Concrete Needed (with waste)	Raw Volume
Small (3 piers, 10 in. dia, 3 ft deep)	0.200 cu yd	4.9 cu ft
Medium (4 piers, 12 in. dia, 4 ft deep)	0.512 cu yd	12.6 cu ft
Large (6 piers, 16 in. dia, 5 ft deep)	1.707 cu yd	41.9 cu ft

What Is Cylinder Cubic Yardage?

A cylinder cubic yardage calculator converts round footing or pier form dimensions (like a sonotube) into the cubic yards of concrete needed. It is directly useful for deck post footings, fence post footings poured with a form rather than just the hole, or any other round concrete pier.

Cylinder Cubic Yardage: Pros and Cons

Pros

Handles multiple identical forms at once, matching how footings and piers are typically poured in a set
Reuses the same NRMCA-sourced 4-10% overage guidance as the Concrete Slab and Concrete Footing calculators for consistency
Common sonotube sizes (6-24 in.) are covered directly by the diameter input

Cons

Doesn't determine what diameter or depth your footing needs. That's a structural or code question for your local building department or an engineer, and it is outside this calculator's material-quantity scope
Assumes all forms are the same size. A project with mixed pier sizes needs each size calculated separately and the totals added
Doesn't include the post-hole excavation itself. See the Post Hole Concrete calculator if you're setting a post without a separate form, just filling the hole directly

Cylinder Cubic Yardage: What a Pro Checks

Set your form depth to your local frost line, not a number from another project. Frost depth is a local building-code question, and it varies significantly by climate and jurisdiction.
Add the same 4-10% overage NRMCA recommends for a slab pour to a footing or pier pour too, since it covers the same form variance and spillage regardless of the shape being filled.
Calculate each size separately if your project mixes pier diameters or depths. Averaging them into one input under- or over-orders concrete for the piers that don't match the average.

Frequently Asked Questions

How much concrete do I need for a round footing or pier?

Multiply the form's cross-sectional area (from its diameter) by its depth to get volume per form. Multiply by the number of forms, add a waste allowance (commonly 4-10% per NRMCA guidance), then convert to cubic yards. 4 piers at 12 in. diameter and 4 ft deep need about 0.51 cubic yards.

What is a sonotube?

A sonotube is a round cardboard concrete form, commonly used for deck post footings and other round concrete piers. It's poured with concrete, left in place or stripped away once cured, and comes in standard diameters (commonly 6 to 24 in.).

How deep should a concrete pier or footing be?

This depends on your local frost line depth and structural requirements, which vary significantly by climate and jurisdiction. Check your local building code rather than assuming one depth applies everywhere.

Should I order concrete for multiple piers as ready-mix or bags?

For a small number of piers (a typical deck's worth), bagged concrete is often practical and avoids a ready-mix delivery minimum. For a larger project needing several cubic yards, ready-mix delivery is usually more economical. This calculator's cubic yard figure works for planning either purchase method.

Is this the same as the Post Hole Concrete calculator?

Not quite. Post Hole Concrete subtracts the post's own volume from a hole filled directly with concrete around it. This calculator is for a form (like a sonotube) filled entirely with concrete, with no post displacing volume inside it.

Sources

NRMCA CIP 31: Ordering Ready Mixed Concrete (4-10% overage guidance) (opens in a new tab)

Measurement