Construction

Verified calculator with a transparent formula

Construction

Concrete Pier Footing Calculator.

Estimates the volume of concrete needed for a cylindrical pier footing and the weight of that concrete.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Measure the diameter and depth of one pier in feet.

  2. 2

    Enter the number of identical piers.

  3. 3

    The calculator computes the volume of one pier using the cylinder formula.

  4. 4

    It multiplies by the number of piers to get total volume and weight.

pi * (diameter / 2)^2 * depth * num_piers

Frequently asked questions

How do I convert cubic feet to cubic yards?

Divide the total cubic feet by 27. For example, 75.4 ft³ ÷ 27 ≈ 2.79 yd³.

What is the weight of concrete per cubic foot?

Standard concrete weighs about 150 pounds per cubic foot, but it can vary with mix and moisture.

Should I order extra concrete?

Yes, it's wise to order 5-10% extra to account for spillage, uneven excavation, and variations in the mix.

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Results

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Total Concrete Volume

—ft³

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Estimate for general guidance only — verify important decisions with an appropriate professional.

How it works

Estimates the volume of concrete needed for a cylindrical pier footing and the weight of that concrete.

  1. Measure the diameter and depth of one pier in feet.
  2. Enter the number of identical piers.
  3. The calculator computes the volume of one pier using the cylinder formula.
  4. It multiplies by the number of piers to get total volume and weight.

Formulas

The math behind this calculator, written out so you can verify the result.

Cylinder Volume

V = π × (d/2)² × h

The volume of a cylindrical pier is the area of the circular base (πr²) times the height (depth).

Example:

Input: d = 1.5 ft, h = 3 ft

Calculation: π × (0.75)² × 3

Result: ≈ 5.30 ft³ per pier

Real-world use cases

Where this calculation shows up in everyday life.

Deck Footings

Determine concrete needed for cylindrical footings supporting deck posts.

Example: A 12-inch diameter, 3-foot deep footing for a deck post.

Fence Posts

Calculate concrete for setting fence posts in cylindrical holes.

Example: Six 10-inch diameter holes, 2.5 feet deep.

Structural Piers

Estimate material for concrete piers used in foundations or carports.

Example: Four 18-inch diameter piers, 4 feet deep.

Tips and common mistakes

Tips

  • Always measure the actual hole diameter, which may be larger than the post due to digging.
  • Use a concrete calculator to convert volume to bags: one 60-lb bag yields about 0.45 ft³.
  • Add 10% to your order to avoid running short.
  • Check local building codes for minimum footing sizes and depths.

Common Mistakes to Avoid

  • Using the post diameter instead of the hole diameter.
  • Forgetting to multiply by the number of piers.
  • Not accounting for the flared base of some footings, which increases volume.

Assumptions and limitations

  • Use the stated inputs and units.
  • Results are estimates for planning and education.
  • Check measurements and source data before making an important decision.