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Calculators & guides

Round Footing Concrete Calculator

Calculate solid cylindrical footings or empty round holes, including repeated pours.

Units

Geometry dimensions — schematic, not to scaleD (diameter)H
Schematic · not to scale · quantity repeats the entire solid

Concrete & bag assumptions

Density is the placed concrete density, not dry bag weight. Defaults are examples for normal-weight concrete. Bag weight does not determine yield; use the mixed yield printed on your product.

Estimate cost (optional · USD)

All cost fields are optional and user-entered. Ready-mix and bags are alternatives, never added together. No average or local prices are assumed — use a real quote. Labor per area is available only for shapes with a defined footprint.

Formula & solid model

V = π × (D/2)² × H × Q

All lengths convert to metres before calculation. Blank waste = 0%. Zero dimensions or quantity produce zero volume. Display values are rounded; costs and bags use unrounded volumes.

Round footing / hole · incl. 10% waste

You need approximately 0.128 cubic yards

3.456 ft³ · 0.098 m³ · 97.86 litres

Volume

UnitExact+10% waste
Cubic yards0.1160.128
Cubic feet3.1423.456
Cubic metres0.0890.098
Litres88.9697.856

Placed weight · incl. waste

518.36 lb / 235.13 kg

Density: 150 lb/ft³ · weight = volume × density

Selected premix bags · incl. waste

6 × 80 lb bags

Yield: 0.6 ft³ / bag · total volume ÷ yield, rounded up.

Estimate inputs & formula

Diameter (D): 24 in · Depth (H): 12 in · Quantity (Q): 1

V = π × (D/2)² × H × Q

Estimate only, not engineering advice. Actual needs vary with subgrade, forms and spillage. Confirm final quantities and product yields with your supplier or contractor before ordering.

What this calculates

Each footing is a solid cylinder. Use the concrete depth, excluding gravel. For a hole containing a square post, use the post-hole calculator to subtract that post.

Formula

V = π × (diameter/2)² × depth × quantity

Worked example

Four 1 m diameter footings, 0.5 m deep

  1. 1.Per footing: π × 0.5² × 0.5 = 0.392699 m³
  2. 2.Four footings: 1.570796 m³
  3. 3.With 10% waste: 1.727876 m³

Common mistakes

  • Entering radius instead of diameter.
  • Including gravel depth in the concrete depth.

Frequently asked questions

Does this subtract a post?

No. This is a solid cylinder. Use the post-hole tool for square post displacement or the tube tool for a concentric round void.