Fence Material Calculator
Posts, rails, pickets & concrete
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Standard: 8 ft OC
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Formula & explanation
Posts are placed at regular spacing (8 ft on-center typical) plus one to close the run. Rails run horizontally between posts — 3 for privacy fences, 2 for picket or rail styles. Pickets count uses the board width plus a 10% cut allowance. Each post needs about 2 bags of concrete in average soil.
Example calculation
100 ft of privacy fence, 8 ft post spacing:
Posts = ceil(100÷8)+1 = 14 posts. Rails = 13 sections × 3 = 39 rails. Pickets = (100÷0.166)×1.1 ≈ 662 boards. Concrete = 28 bags.
Buying & project-planning tips
- Call 811 (utility locator) before digging any post holes — it's free and required by law.
- Set posts in concrete and let cure 24–48 hours before attaching rails.
- Check local fence-height limits and setback rules before building — permits are often required.
- Use hot-dipped galvanized or stainless fasteners to prevent rust streaks on cedar.
- Leave a 2-inch gap under fence boards to prevent rot from ground contact.
Frequently asked questions
How deep should fence posts be?+
At least 1/3 of the post length, or below your local frost line — typically 24–36 inches. Set in concrete for stability.
How far apart should fence posts be?+
8 feet on-center is standard for most fences. Wider spacing (10 ft) works with heavier rails; narrower (6 ft) for tall or wind-exposed fences.
Do I need a permit for a fence?+
Most jurisdictions require a permit for fences over 3.5–6 ft tall (varies). Front yards often have stricter height limits. Check with your local building department.
How much concrete per fence post?+
About 2 bags (40-80 lb) per post in average soil, more in soft soil. Fill the hole 2/3 with concrete, slope it away from the post for drainage.