ConcreteQty

Fence and deck post planner

Post Hole Concrete Calculator

Calculate concrete for fence and deck post holes, including optional post displacement.

Project

DIAMETERDEPTH

Formula

How the result is calculated

Hole volume = π × hole radius² × depth. When a post diameter is entered, its cylindrical volume is subtracted before the hole count is applied.

Worked example

Check the order logic

Enter the number of holes once. The result totals all holes and shows every common bag size without another calculation.

Assumptions

Waste and supplier rounding stay editable

The launch defaults are 10% waste and upward rounding to 0.25 yd³ or 0.10 m³. Open “Adjust assumptions and costs” to use your supplier’s increment, actual prices, density, truck capacity, or product bag yield.

Questions

What this calculator does

Should I enter hole or post diameter?

Hole diameter is required. Post diameter is optional and only controls displacement.

Can I leave post diameter blank?

Yes. ConcreteQty then assumes the full hole is filled with concrete.

Does this choose the correct hole depth?

No. Depth must follow your project requirements and local rules.

Bag yields follow the cited manufacturer data. See sources and review dates.