Fence Post Spacing: How Far Apart by Fence Type

Fence post spacing by fence type

"On center" (OC) means the distance from the center of one post to the center of the next. All the numbers below are OC, and all of them are maximums unless the fence is a panel system, where the number is exact.

Fence type	Maximum OC spacing	What to lay out	What sets the number
Wood privacy, vertical boards, 2x4 rails	8 ft	7'10" or less	2x4x8 rails must reach post centers (America's Fence Store)
Wood, high wind, heavy snow, or horizontal boards	6 ft	6 ft or less	Wind load on a solid face, and board span for horizontal styles
Chain link, residential (11 or 11½ gauge)	10 ft	10 ft or less, equalized	ASTM F567 section 4.1
Chain link, 9 gauge or taller fences	8 ft	8 ft or less	Heavier fabric and more wind area
Vinyl, 6-ft wide panels with 5x5 posts	Exact	About 73" to 73¼"	Panel width plus post width (Bufftech manual)
Vinyl, 8-ft wide panels	Exact	96"	Panel width plus post width
Aluminum, 6-ft sections, 2" posts	Exact	72½" typical	Manufacturer's layout (QCE Fence)
Aluminum, 8-ft sections	Exact	About 96"	Manufacturer's layout
Split rail, 11-ft rails	Set by rail	10'4" to 10'6"	Rail overlap inside the mortise (Split Rail Fence Store)
Split rail, 8½-ft rails	Set by rail	7'10" to 8'	Rail overlap inside the mortise

For vinyl and aluminum, treat the table as a starting point and use the number printed in your manufacturer's install sheet. Panel systems are built to fit a specific OC dimension, and a few inches of error means a panel that will not seat. America's Fence Store's vinyl guide puts the layout tolerance at plus ¼ inch.

The 8-foot rails on 8-foot centers trap

An 8-foot 2x4 is 96 inches long. It sounds like it should fit perfectly on 8-foot centers. Whether it does depends on how the rails attach.

Rails set between posts. If the rails fit between the posts (in a notch, on a bracket, or toe-screwed to the post sides), the rail length is the gap between post faces. A 4x4 is 3½ inches wide, so at 96 inches OC the gap is 96 − 3½ = 92½ inches. An 8-foot rail covers that with room to trim.

Rails on post centers. If the rails are face-mounted and butt together on the middle of each post, each rail has to span exactly one full OC distance. At 8 feet OC that is exactly 96 inches with zero margin. Any post that lands ½ inch wide, or any board that comes from the yard at 95¾ inches, leaves you a rail that stops short of the post center.

There are two ways around it:

1. Lay out at 7'10" or less. America's Fence Store tells DIY customers to set posts at 7'10" so the 2x4x8 rails span properly. You trim 2 inches off each rail, which is easy, instead of trying to stretch one, which is impossible.
2. Use 16-foot rails across two bays. A 2x4x16 spans two bays and lands on every other post center. Stagger the joints between the top, middle and bottom rails so no single post carries every splice.

Equalized spacing: no stub sections

If you start at one end and mark a post every 8 feet, whatever is left lands at the far end. On a 50-foot run that gives you six 8-foot bays and one 2-foot stub. It looks wrong and it wastes a rail.

Instead, divide each run into equal bays:

• Bays = run length ÷ maximum spacing, rounded up
• OC spacing = run length ÷ bays
• Posts on the run = bays + 1 (the two ends are terminal posts)

Worked example: a 50-foot run

Step	Math	Result
Maximum spacing	Wood privacy	8 ft
Bays	50 ÷ 8 = 6.25, round up	7 bays
OC spacing	50 ÷ 7 = 7.143 ft	85.7", about 7'1¾"
Posts	7 + 1	8 posts (2 terminal, 6 line)

Every bay is 7'1¾", which is under both the 8-foot maximum and the 7'10" layout target. Using the 7'10" target as your maximum gives the same answer here: 50 ÷ 7.83 = 6.4, which also rounds up to 7 bays.

For panel fences, equalizing does not apply the same way. You keep the fixed panel OC and cut one panel down at the end of the run, or cut two panels equally so the short sections sit at both ends and look intentional.

Why you calculate per side, not from total length

Every corner, end post and gate restarts the spacing. A post at a corner is shared by two runs, and the first line post on the new run is measured from that corner, not from the last line post on the previous side.

Take a backyard with three 50-foot sides. If you divide the total 150 feet by 8, you get 18.75, rounded up to 19 bays. Worked per side, each side needs 7 bays, so the real total is 21 bays. Across a whole project this undercount shows up as missing posts, missing rails and a second trip to the yard.

CalculatorLay out each run and get equalized spacing in the fence calculator

Terminal posts are not part of the spacing math

Corner posts, end posts and gate posts are terminal posts. ASTM F567 section 4.2 describes them as the posts that set the beginning and end of each continuous length of fence and mark abrupt changes in direction or grade. They are fixed by the layout, and the line posts are spaced between them.

That has two practical consequences:

• A gate splits a run into two runs. Measure from the corner to the first gate post, equalize that stretch, then measure from the second gate post to the next corner and equalize that separately.
• The gate opening is set by the gate, not the spacing. A 4-foot gate needs its posts set at the gate width plus the hinge and latch gaps the gate manufacturer specifies. Do not try to make the gate opening match the line bays.

Terminal posts also get bigger holes and deeper footings, and chain link terminals are a larger pipe size than line posts. See how deep fence posts should be for the depth and diameter numbers.

How to lay out posts with a string line

You need two stakes or the terminal posts themselves, mason's string, a 100-foot tape, marking paint or flags, and a helper if you have one.

1. Call 811 first. Utility marking is free and required before you dig. Wait for the marks before you set any layout.
2. Set the terminal posts. Mark every corner, end and gate post location first. If you have a survey, measure from the property pins, and keep the fence a little inside the line unless you and your neighbor have agreed otherwise.
3. Run a string between terminals. Pull it tight at the height of the post faces, not the centers, so you have a clean reference line. Keep the same side of every post on the string.
4. Measure each run along the string. Measure horizontally along the line of the fence, not along a sagging tape. On sloped ground ASTM F567 measures the interval parallel to the grade, which is what a racked fence follows. A stepped fence is laid out level.
5. Equalize and mark. Work out the bays and OC spacing for that run, then hook the tape on the center of the first terminal and mark each line post center with paint or a flag. Mark cumulative distances (85¾", 171½", and so on) rather than moving the tape each time, so small errors do not add up.
6. Check the last bay. The final mark should land on the center of the far terminal. If it is off by more than about ½ inch, re-measure the run before you dig.

When to space posts closer than the maximum

The maximums above assume normal residential conditions. Tighten the spacing when:

• The fence is solid and exposed. A 6-foot privacy fence is a sail. In open areas, on hilltops, or in coastal wind zones, 6-foot spacing puts less load on each post.
• You get heavy wet snow. Snow drifts against solid fences and loads the rails.
• The boards run horizontally. Horizontal boards span from post to post, so the post spacing is the board span. Shorter spans keep the boards from cupping and sagging.
• Your local code or HOA says so. Some pool barrier, HOA and commercial specifications set their own maximums.
• The run changes grade a lot. Shorter bays let a stepped fence follow the ground in smaller, less noticeable steps.

Closer spacing costs you more posts and holes, but it does not add much lumber, since the rails and boards cover the same length either way.

CalculatorPrice a wood fence at 6 or 8 foot spacing