How far apart should chain link fence posts be?

Line posts go no more than 10 ft on centre between terminal posts, per the CLFMI product manual. Terminal posts are the ends, corners, gate posts and any pull post on a long run, and they are normally one size larger in outside diameter than the line posts.

How deep should chain link fence posts be set?

The CLFMI minimum is 24 in plus 3 in for every foot of fence height over 4 ft. That is 24 in at 4 ft, 30 in at 6 ft and 36 in at 8 ft. Local frost depth, soil conditions and wind load can all require deeper, and where frost governs it is a local number.

How wide should the post hole be?

At least four times the largest cross section of the post. For a common 2 3/8 in terminal post that is about 9 1/2 in. Gate posts need larger footings, listed in ASTM F567.

How many lengths of top rail do I need?

Top rail is supplied in 21 ft lengths and runs continuous through the line post tops, so divide your run by 21 rather than counting bays. Splices use sleeves of at least 6 in.

How many tension bands per post?

The manual specifies the bolts at no more than 12 in on centre, so a 6 ft fence takes about five per terminal post. Tension bands go on terminal posts only; line posts take tie wires.

What strength concrete do chain link footings need?

The CLFMI manual specifies 2,500 psi at 28 days. That is ordinary bagged concrete mix, not a special order.

Do I need a permit for a chain link fence?

That is entirely local, and height limits, setbacks and front-yard rules vary by municipality. Nothing on this page speaks to it. Ask your building department before you dig.

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Chain Link Fence Calculator

Post spacing and footing depth from the CLFMI product manual

Chain link is the one fence with a real published standard behind it. The Chain Link Fence Manufacturers Institute caps line posts at 10 ft on centre and gives footing depth as a formula, not a number: 24 in at a 4 ft fence and 3 in deeper for every foot above that. This works your run against both.

Chain link takeoff

Total run

Fence height

Line post spacing (on centre)

End posts

no.

Corner posts

no.

Gate openings

no.

Top rail

Tie wire spacing (your practice)

Post spacing, footing depth and rail lengths come from the CLFMI product manual.

Specification summary

Generated from on . Reopen that address to reproduce these figures exactly.

Entered

Result

Chain link layout: posts, rail and footing depth

Worked example

A 100 ft straight run of 6 ft chain link, an end post at each end, no corners, no gates, with top rail.

Bays. 100 ft at 10 ft on centre is 10 bays, so 9 line posts between the two ends.
Footings. 6 ft is 2 ft over the 4 ft base, so 24 + 6 = 30 in deep. Not 24, and not a third of the post.
Rail. Rail comes in 21 ft lengths, so 100 ft needs 5 lengths and 4 sleeves, not 10 pieces between posts.
Tension bands. At 12 in on centre up a 6 ft post that is 5 per terminal post, 10 in total.
Concrete. 11 posts at 30 in deep in a 9 1/2 in hole is 13.5 cu ft, or 23 sixty pound bags.

Push the spacing past 10 ft and the verdict fails: not because a building code says so, but because the people who make the fabric say so.

The formula

Two published rules and some counting:

depth = 24 + 3(h − 4) bays = ⌈ L / s ⌉ rail = ⌈ L / 21 ⌉

depth: footing depth, in, from the CLFMI minimum
h: fence height, ft
L: run length, ft
s: line post spacing, ft, capped at 10
21: the length top rail is supplied in, ft

The rail term is the one that catches people out. Rail is continuous through the line post tops in 21 ft lengths, so you buy by the run and not by the bay.

Why chain link has a real answer and wood fencing does not

Wood fencing has conventions. Chain link has a published product manual, written by the institute whose members make the fabric, and referenced by the ASTM installation standard. That means the spacing and the footing depth on this page are quotable, which is rare for fencing of any kind.

The footing formula is the clearest example. Search for chain link post depth and you will be told a third of the post length, or 24 in, or 30 in, with no source attached. The manual says 24 in at 4 ft and 3 in more per foot above that, so a 6 ft fence is 30 in and an 8 ft fence is 36 in.

What the manual will not do is override your ground. It says plainly that soil conditions, local frost depth, height and wind load may require larger or deeper footings, and frost depth is a jurisdiction number that cannot be published as one figure. Treat the output as a floor.

At 8 ft and above with fine mesh the manual stops giving a general answer at all and sends you to its wind load guide. This page passes that instruction on rather than inventing a number to fill the gap.

The footing depth formula nobody quotes

Post spacing has a hard cap:

Line post- Intermediate posts set no greater than 10 feet on center between the terminal posts.
CLFMI Product Manual CLF-PM0610, Chain Link Fence Manufacturers Institute, updated October 2015

And footings are a formula, not a number:

Minimum footing depth, 24 in. (609.6 mm) plus an additional 3 in. (76.2 mm) for each 1 ft. (305 mm) increase in the fence height over 4 ft. (1220 mm). Minimum footing diameter four times the largest cross section of the post.
CLFMI Product Manual CLF-PM0610, framework installation

Twenty-four inches at a 4 ft fence, and 3 in deeper for every foot above that. A 6 ft fence wants 30 in, an 8 ft fence 36 in. Almost every guide on the subject says “a third of the post” or repeats a single depth for all heights, and neither is what the manufacturers’ own manual says.

Diameter is four times the post’s largest cross section. The manual adds that soil, frost depth, height and wind load may require more, so this is a floor and not a design.

When specified, install 21 ft. (6.4 m) lengths of rail continuous thru the line post or barb arm loop top. Splice rail using top rail sleeves minimum 6 in. (152 mm) long.
CLFMI Product Manual CLF-PM0610, top rail

Rail arrives in 21 ft lengths, not 10 ft, which is why the rail count on this page is not simply the post count minus one.

Concrete for post footings shall have a 28-day compressive strength of 2,500 psi. (17.2 MPa).
CLFMI Product Manual CLF-PM0610, concrete

Tie wire and hog rings are specified as 'per ASTM F626' without a spacing, so this page treats tie spacing as an input rather than publishing a figure the manual does not give.

Frequently asked questions

How far apart should chain link fence posts be?: Line posts go no more than 10 ft on centre between terminal posts, per the CLFMI product manual. Terminal posts are the ends, corners, gate posts and any pull post on a long run, and they are normally one size larger in outside diameter than the line posts.
How deep should chain link fence posts be set?: The CLFMI minimum is 24 in plus 3 in for every foot of fence height over 4 ft. That is 24 in at 4 ft, 30 in at 6 ft and 36 in at 8 ft. Local frost depth, soil conditions and wind load can all require deeper, and where frost governs it is a local number.
How wide should the post hole be?: At least four times the largest cross section of the post. For a common 2 3/8 in terminal post that is about 9 1/2 in. Gate posts need larger footings, listed in ASTM F567.
How many lengths of top rail do I need?: Top rail is supplied in 21 ft lengths and runs continuous through the line post tops, so divide your run by 21 rather than counting bays. Splices use sleeves of at least 6 in.
How many tension bands per post?: The manual specifies the bolts at no more than 12 in on centre, so a 6 ft fence takes about five per terminal post. Tension bands go on terminal posts only; line posts take tie wires.
What strength concrete do chain link footings need?: The CLFMI manual specifies 2,500 psi at 28 days. That is ordinary bagged concrete mix, not a special order.
Do I need a permit for a chain link fence?: That is entirely local, and height limits, setbacks and front-yard rules vary by municipality. Nothing on this page speaks to it. Ask your building department before you dig.

Check these numbers yourself

CLFMI Product Manual CLF-PM0610Chain Link Fence Manufacturers Institute, updated October 2015. Free PDF. Post spacing, footing depth, rail lengths and concrete strength.
ASTM F567, Standard Practice for Installation of Chain-Link FenceASTM International. The installation standard the CLFMI manual references. Purchase required.

How every figure here is verified: Sources & Method. Who builds this: About. Found something wrong? Tell us and it gets fixed or removed.

Figures on this page last checked against the source documents on 2026-09-07. Codes are amended locally; confirm against the edition your jurisdiction enforces.

Related calculators

Minimums, not a design. Footing depth is the CLFMI minimum and local frost depth, soil and wind load can require more. Fences 8 ft and over with fine mesh need the CLFMI wind load guide. Height, setback and permit rules are local.