Standard fence post spacing is 6 to 8 feet on center. For most privacy fences, 8-foot spacing is common because fence panels and rails come in 8-foot lengths. For split-rail or ranch-style fences, 8–10 foot spacing is typical. For chain-link, 10-foot post spacing is standard. Shorter spacing (6 ft) provides more rigidity, especially for tall or solid privacy fences in windy areas.

For a standard 4×4 post in a 10-inch diameter hole, 2 feet deep: about 1 bag of 80lb concrete. For a 3-foot deep hole: 2 bags. For corner and end posts: always use at least 2 bags regardless of depth. Gate posts should use 3 bags each. Fast-setting concrete bags typically cover a 10-inch diameter × 2-foot deep hole per 50lb bag.

Fence post holes should be at least 1/3 of the total post length deep. For a 6-foot fence, bury posts at least 2 feet deep. In cold climates, post holes must go 6–12 inches below the frost line to prevent frost heave. Most codes require a minimum 18–24 inch depth. Check local frost depth maps for your area.

The diameter of a fence post hole should be 3 times the post diameter. For a 4×4 post (3.5 actual inches), dig a 9–10 inch diameter hole. For a 6×6 post, dig a 12–14 inch hole. Wider holes allow more concrete, which provides a stronger, more stable footing.