Fence Calculator

How Many Posts, Rails, and Pickets?

Sections = fence length ÷ post spacing (round up) · Posts = sections + 1, plus one for each corner, end, and gate

Worked example. 100 ft of 6 ft privacy fence with posts every 8 ft:

• 13 sections and 14 posts.
• 39 rails at 3 per section.
• 234 boards: 96 in ÷ 5.5 in = 17.5, so 18 boards per section.
• 42 bags of concrete: 3 bags per 4 × 4 post.

Post Holes and Concrete

Quikrete’s instructions for setting posts:

• Hole width: three times the post width. For a 4 × 4 (3.5 in actual) that’s about 10.5 in.
• Hole depth: one-third to one-half of the post’s above-ground height, plus 6 in. The calculator uses one-third, the minimum.
• Gravel: 6 in of gravel or crushed stone in the bottom for drainage.
• Concrete: fill to 3–4 in below the ground.

A 50 lb bag of Quikrete Fast-Setting Concrete yields about 0.375 cu ft. Quikrete’s own example, two bags for a 3 in post in a 9 in × 30 in hole, matches what the calculator works out.

Frost depth and local rules can call for deeper holes. Call 811 before you dig to have buried utility lines marked.

Post Spacing

HomeGuide puts post spacing at 6–8 ft. Prebuilt panels set the spacing for you, usually 6 or 8 ft. Closer posts make a stiffer fence and help in windy areas or with heavy materials.

What It Costs

HomeGuide’s installed prices per linear foot:

The fence cost calculator compares doing it yourself with hiring a pro.