How to measure for your fence project
- Measure your fence line. Walk the perimeter or each run with a measuring tape and record every straight segment in feet. For a full enclosure, add all four sides (or as many as you need) to get the total linear footage. If one side already has a wall or existing fence, measure only the open runs you are fencing. Note any gate openings — you will subtract those from the measured length when you enter the number.
- Choose a post spacing. Most wood and vinyl panel fences use 6- to 8-foot spacing; split-rail and chain-link fences can stretch to 8–10 feet. Tighter spacing (6 ft) means more posts but a sturdier, more wind-resistant fence. Enter your chosen spacing in the Post Spacing field. Not sure? Use 8 feet as a solid starting point for most residential fencing.
- Read the result and plan for corners and gates. The calculator gives you the posts and sections for one straight run. For every corner or end-post you add to your plan, add 1 post to the total. For every gate, add 2 posts (one on each side of the opening) and subtract the gate width from your measured fence length before entering it. Order one or two spare posts so you are covered if a hole placement shifts.
How the fence calculator works
The calculator divides your fence length by the post spacing and rounds up to the nearest whole number — that gives you the section count. Posts are always one more than sections because each section has a post at both ends and adjacent sections share a post. For a 100-foot run at 8-foot spacing: 100 ÷ 8 = 12.5, rounded up to 13 sections, plus 1 = 14 posts. At 6-foot spacing the same run gives ceil(100 ÷ 6) = 17 sections and 18 posts. The rounding-up step ensures the last section is never longer than your chosen spacing, which matters for panel fences where the panel must fit between posts.
Which type are you estimating?
Solid-board privacy fence
Vertical boards run edge-to-edge or with a small gap for a solid visual screen. Posts are typically 6 to 8 feet apart on a 6-foot-tall fence. This style is the most common residential choice and works with the calculator's default 8-foot spacing. Note that this calculator counts posts and sections only — picket/board quantities are not included.
Enter: Enter post spacing: 6 or 8 ft. Typical height: 6 ft.
Decorative picket fence
A shorter, open-style fence (3–4 ft tall) used along front yards and gardens. Post spacing of 6 to 8 feet is standard. Like privacy fencing, the calculator gives you post and section counts; the number of individual pickets depends on picket width and gap, which you figure separately.
Enter: Enter post spacing: 6 or 8 ft. Typical height: 3–4 ft.
Shadowbox (board-on-board) fence
Boards alternate on opposite sides of the rail so each side looks finished and the fence allows slight airflow. Post spacing is the same as solid privacy — 6 to 8 feet — but each section uses more boards than a standard privacy fence because the boards overlap. Use 8 ft spacing as your default, then figure boards separately.
Enter: Enter post spacing: 6 or 8 ft. Typical height: 6 ft.
Split-rail fence
A rustic two- or three-rail fence, popular for pastures and large lots. Rails are longer and posts can be spaced 8 to 10 feet apart, so fewer posts are needed per linear foot. Enter 8 or 10 ft as the spacing for an accurate post count. Note that split-rail posts are routed to accept rails — no separate section panels are involved.
Enter: Enter post spacing: 8 or 10 ft. Typical height: 3–4 ft.
Chain-link fence
Chain-link fabric stretches between terminal posts (corners, ends, gates) and line posts spaced up to 10 feet apart. Use 10 ft spacing in the calculator for standard residential chain-link. Terminal posts are set in concrete footings; add them at every corner and gate in your final materials list.
Enter: Enter post spacing: 8 or 10 ft. Corner and gate posts are additional.
Tips & ways to save
- Always measure along the ground, not from above — slopes make a fence run longer than a straight-line measurement.
- For a full enclosure, subtract all gate openings from the total perimeter before entering the length. Then add 2 posts per gate to your post count.
- Order one or two spare posts above the calculator total — misplaced holes, split lumber, or a shifted corner happen on almost every project.
- Set end and corner posts first, stretch a string line between them, then mark the intermediate post locations. This keeps spacing consistent and the fence line straight.
- In most jurisdictions, fences over 6 ft require a permit. Check local codes before buying materials — height limits and setback rules vary by municipality.
Fence length to enclose a square lot
| Lot size | Side length | Fence perimeter |
|---|---|---|
| ¼ acre (10,890 sq ft) | 104 ft | 417 ft |
| ½ acre (21,780 sq ft) | 148 ft | 590 ft |
| 1 acre (43,560 sq ft) | 209 ft | 835 ft |
| 2 acres (87,120 sq ft) | 295 ft | 1,181 ft |
| 5 acres (217,800 sq ft) | 467 ft | 1,867 ft |
Assumes a square lot — the most fence-efficient shape. A long, narrow lot of the same acreage needs more fencing. Enter your measured perimeter above to get exact posts and sections.
Frequently asked questions
How many fence posts do I need for 100 feet?
How many pickets do I need for a fence?
How much fence do I need to enclose an acre?
How do I account for corners and gates when counting fence posts?
What post spacing should I use for a wood privacy fence?
How many posts and sections does a 200-foot fence need?
Sources
Related calculators
Reviewed by the BackyardCalc editorial team. Figures are computed from the formula above and checked against manufacturer yields.