Fence Post Concrete Calculator

Calculate concrete volume per fence post hole and total 50, 60, or 80 lb bags needed. Enter hole diameter, depth, post size, and post count. Estimate only.

Common questions

How many bags of concrete per fence post?
It depends on hole diameter, hole depth, and post size — the concrete fills the annular space around the post. This calculator subtracts the post volume and converts the remainder into 50 lb, 60 lb, or 80 lb bag counts.
How deep should a fence post be set?
A common starting point is one-third of the above-grade post height, and always below the local frost line. Gate posts and corner posts carry side load and are typically set deeper and wider than line posts.
Should the hole be wider at the bottom?
In frost-prone ground a bell-shaped bottom resists frost jacking, because the widened footing has to lift more soil to move. A straight or tapered-narrow hole is easier for frost to push upward.

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