How Much Concrete Per Fence Post?
Setting fence posts in concrete is the classic small-pour job, and two simple rules size it. Make each hole about three times the post's width across, and bury roughly one-third of the post's above-ground height. For a 6-ft-tall fence, that means about a 2-ft-deep hole; for gate and corner posts, which take more force, go deeper — use a 9-ft post with 3 ft in the ground.
How much concrete per hole
A post hole is a cylinder, so its volume is π × radius² × depth, minus the space the post occupies. A common 10-inch-wide hole, 2 ft deep, takes roughly 1 to 1.5 cubic feet of concrete — about two to three 60-lb bags per post. Multiply by the number of posts in your run.
| Hole size | Concrete per post | 60-lb bags |
|---|---|---|
| 8 in wide × 2 ft deep | ~0.7 cu ft | ~2 |
| 10 in wide × 2 ft deep | ~1.1 cu ft | ~2–3 |
| 12 in wide × 3 ft deep | ~2.4 cu ft | ~5 |
Why bagged — and why fast-setting
Fence posts are small, separate pours scattered along a line, which is exactly the wrong job for a ready-mix truck. Bagged mix is the tool, and fast-setting (red-bag) mix is popular for a reason: you can often set a post and move on without mixing in a tub at all. With many products you pour the dry mix into the hole around the post, add water, and let it set in 20–40 minutes — far quicker than standard mix.
Setting tips
Set the post on a few inches of gravel for drainage, brace it plumb before you pour, and crown the concrete slightly above grade so water runs away from the post rather than pooling against it. Let it set before hanging panels or applying real load.
Estimate per-post and total bags with the post hole calculator, which handles the hole geometry and post count, or see the full fence post project guide for a step-by-step walkthrough.