Fence Calculator
Enter your fence dimensions and layout to instantly calculate how many posts, panels, bags of concrete, and pickets you'll need.
Post spacing
Fence type
Enter your fence dimensions above to see results
How to Use This Calculator
Choose your fence layout at the top. Straight is for a single run of fencing — a side yard, a front fence, or any non-enclosing section. Rectangle yard calculates the full perimeter of a rectangular area from its length and width. Custom lets you enter any total perimeter you've already measured, useful for L-shaped or irregular yards.
Select your post spacing. Eight-foot spacing is the industry standard for most residential projects. Six-foot spacing is better for vinyl fencing, high-wind areas, or anywhere you need a stiffer fence. Ten-foot spacing is less common but reduces post count on long straight runs where panels can support the wider span.
Enter the number of gates you plan to install. Each gate requires two extra posts — one on each side of the opening. The gate itself is not counted as a fence panel.
Select your fence type. Wood privacy fencing shows an additional picket count estimate. Chain link, vinyl, and wrought iron are sold as pre-fabricated panels — consult your supplier for panel widths. All fence types show post count, panel count, and concrete bags, since every fence type uses set posts.
Formula
All outputs are derived from the fence perimeter, post spacing, and gate count using standard contractor formulas.
Perimeter Straight: Perimeter = Fence length Rectangle: Perimeter = 2 × (Length + Width) Custom: Perimeter = entered directly Posts and panels Panels = ⌈ Perimeter ÷ Post spacing ⌉ Posts = Panels + 1 + (2 × Number of gates) Concrete 60-lb bags = Posts × 2 Wood pickets (1×6 dog-ear, 5.5" effective width) Pickets per panel = ⌈ Spacing (in) ÷ 5.5 ⌉ Total pickets = Pickets per panel × Panels
Posts always equal panels + 1 because you need one post at each end of a straight run. Gate posts count separately — each gate opening replaces a fence panel and adds two posts (one per side). If your fence has a gate in a corner, you may only need one new post, but this calculator uses the conservative 2-post-per-gate figure.
Two 60-lb bags of concrete per post is the standard residential figure for a 4×4 post in a 10-inch diameter hole at 2-foot depth. Each 60-lb bag yields 0.45 cubic feet of finished concrete. That 10-inch hole at 2-foot depth contains roughly 1.1 cubic feet — two bags (0.90 cu ft) is close to exact for a solidly set post with minimal void.
Picket count uses a 5.5-inch effective width, which matches a standard 1×6 dog-ear picket installed flush. Board-on-board styles (where pickets overlap) will use 20–30% more pickets than this estimate. Check your panel design with your lumber yard before ordering.
Common Project Sizes
Estimates at 8-ft post spacing, 0 gates. Add 2 posts and 4 concrete bags per gate opening.
| Perimeter | Post Spacing | Posts | Panels | 60-lb Bags |
|---|---|---|---|---|
| 50 ft | 8 ft | 8 | 7 | 16 |
| 100 ft | 8 ft | 14 | 13 | 28 |
| 150 ft | 8 ft | 20 | 19 | 40 |
| 200 ft | 8 ft | 26 | 25 | 52 |
| 200 ft | 6 ft | 35 | 34 | 70 |
| 300 ft | 8 ft | 39 | 38 | 78 |
| 400 ft | 8 ft | 51 | 50 | 102 |
Frequently Asked Questions
How many fence posts do I need?
Divide your total fence length by your post spacing (commonly 8 feet), then add 1 for the final end post. For a 100-foot fence at 8-foot spacing: 100 ÷ 8 = 12.5, rounded up to 13 sections + 1 = 14 posts. Add 2 extra posts for every gate opening — one on each side of the gate. This calculator handles all of that automatically.
How many bags of concrete do I need per fence post?
Two 60-lb bags of concrete per 4×4 post is the standard rule for a post set in a 10-inch diameter hole at 2-foot depth. Corner posts and gate posts that take additional lateral load may benefit from a third bag. Each 60-lb bag yields about 0.45 cubic feet of finished concrete — enough to solidly set a standard residential fence post.
What post spacing should I use?
8-foot spacing is the most common for residential wood privacy fences and chain link — it balances panel cost, post count, and structural stability. 6-foot spacing gives a stronger fence and is recommended for high-wind areas, vinyl fencing (which is heavier than wood), or wherever extra rigidity is needed. 10-foot spacing reduces post count and cost but requires heavier rails or panels to bridge the span without sagging.
How many pickets do I need for a wood privacy fence?
Standard 1×6 dog-ear pickets have an effective coverage width of about 5.5 inches. At 8-foot post spacing, each panel needs approximately 17–18 pickets. Multiply by the number of panels to get your total. This calculator uses 5.5 inches per picket — a realistic figure that accounts for the slight overlap of picket edges when installed flush. For a board-on-board style, add 20–25% more pickets.
How deep should fence posts be set?
The standard rule is to bury one-third of the post length, with a minimum of 2 feet below grade. For a 6-foot fence, use 8-foot posts set 2 feet deep. In cold climates, posts must extend below the frost line (check your local frost depth) to prevent heaving. This calculator uses 2 feet as the default post depth for concrete estimates, which is appropriate for most residential applications in moderate climates.
How do I calculate fence materials for an irregular yard?
Use the "Custom perimeter" mode and enter the total linear footage of fencing you need. If your yard has multiple straight runs at odd angles, measure each run separately and add them together before entering the total. Gates reduce the amount of fencing but still require posts on each side — enter your gate count and the calculator adds the extra posts automatically.
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