How Much Fence Post Concrete Do I Need?

Updated 2026-07-28 · Yardly

A leaning fence almost always starts with a weak post footing. The fix is simple: enough concrete per hole. Here’s how to size it before you buy.

Concrete per post

Most posts go in a 10–12 in diameter hole, 2 ft deep. Volume ≈ π × r² × depth. For a 12 in hole at 2 ft: about 1.4 cu ft per post, or roughly 2–3 of the 80-lb bags. The fence post concrete calculator works this from your hole diameter and depth.

Concrete for the whole run

Multiply per-post concrete by the number of posts. A 100 ft fence with posts every 8 ft is about 13 posts:

• 13 posts × 1.4 cu ft ≈ 18 cu ft ≈ 30–33 bags
• Over ~1 cu yd, a ready-mix truck is usually cheaper and far less labor.

The fence project estimator totals post concrete across the whole run so one number drives your order.

Tips for a solid set

• Drop the post, then pour — don’t pre-fill the hole.
• Crown the concrete slightly away from the post to shed water.
• Let it cure before stringing panels.

Plan your run with the fence post concrete calculator or the full fence project estimator.

Frequently asked questions