Fence calculator for posts, wire rolls and panels

How to work out fence posts and rolls

For each side, take off the width of the gates, divide what is left by the post spacing and round up: that gives the bays of fence on that side. You need one post per bay, one more for each gate, and one more for the very first post if the fence is open at the ends.

The corner rule: a corner post ends one side and starts the next, so it counts once. A fence on three sides of a yard (the house is the fourth) has one extra post at the start; a fully closed fence does not, because the last side comes back to the first post. Posts are spread evenly along each run, so with posts no more than 8 ft apart a 20 ft run gets 3 bays of 6 ft 8 in, not two of 8 ft and a short one of 4 ft.

Chain link and welded wire run on around the corners, so the rolls are worked out on the total length minus the gates. The Home Depot guide says the same: buy enough fabric for the full perimeter, minus gate openings. Rigid panels are counted bay by bay, because a cut panel cannot move to another side.

A worked example

In feet (US). The calculator opens with sides of 60, 50 and 60 ft, a 4 ft walk gate on the 50 ft side, a 4 ft high fence in 50 ft rolls, posts every 8 ft and 2 ft in the ground.

• Side A: 60 ÷ 8 = 7.5, so 8 bays and 8 posts
• Side B: (50 - 4) ÷ 2 = 23 ft each side of the gate; 23 ÷ 8 = 2.9, so 3 bays each side, 6 in all, plus the gate post: 7 posts
• Side C: 8 posts
• Posts: 8 + 7 + 8 + 1 (the first) = 24 posts, 4 + 2 = 6 ft long
• Fabric: 60 + 46 + 60 = 166 ft; 166 ÷ 50 = 3.32, so 4 rolls of 50 ft
• Tension wire along the bottom: 166 ft

With 8 ft panels the same sides take 22 panels and still 24 posts.

In metres (UK and elsewhere). Sides of 20, 15 and 20 m, a 1 m gate, mesh 1.5 m high in 25 m rolls, posts every 2.5 m: 24 posts of 2 m, 54 m of mesh, 3 rolls of 25 m and 162 m of line wire for three rows.

How many fence posts: table by length

A straight run with no gates, posts at most 8 ft or 10 ft apart.

Fence length	Posts every 8 ft	Posts every 10 ft	50 ft rolls
50 ft	8	6	1
100 ft	14	11	2
150 ft	20	16	3
200 ft	26	21	4
300 ft	39	31	6

Corners add posts only when they fall between two line posts: each side is spaced on its own, so a square of the same perimeter can need a post or two more than a straight run.

Rolls, panels and posts you can buy

Chain link fabric comes in rolls 4, 5 or 6 ft tall, and the YARDGARD kits count one 50 ft roll per 50 ft of fence. Welded wire also comes in 100 ft rolls, such as the 48 in × 100 ft Origin Point roll. In Europe, mesh comes in 25 m rolls, or 12.5 m depending on the height (Draht-Driller). Enter the roll length you find in the store.

Line posts should be no more than 10 ft apart, and the Home Depot guide sets each hole at about one third of the post length, plus 4 in of gravel. For a 4 ft fence that means 6 ft posts with 2 ft in the ground, the size YARDGARD lists next to 5 ft 6 in posts. You can change the depth in the advanced options. End, corner and gate posts are heavier (2 3/8 in against 1 5/8 in for line posts) and are set in concrete.

Chain link also needs a top rail and one tension wire along the bottom, each as long as the fence: the calculator lists the tension wire, and the line "To fence, minus the gates" is the footage of top rail. In metric mode the default is three rows of line wire, top, middle and bottom, because a fence above about 1.25 m needs a third wire.

Panel fences with 8 ft sections, such as YARDGARD SELECT, put a post at every joint; European panels are 2.5 m wide, with posts 2530 mm apart in the Betafence Nylofor system. The calculator uses the panel width as the post spacing, which rounds up slightly because the post itself adds a little to each bay.

Common mistakes

• Counting posts as length ÷ spacing. You are always one post short: the first one, plus one for each gate.
• Counting corner posts twice. A corner is one post, a heavier terminal post like the end and gate posts.
• Buying fabric across the gate. The gate opening comes off the fabric. Enter the gate width as the distance between the two gate posts: the Home Depot guide leaves an extra 3 3/4 in between the posts for hinges and latch.
• Posts as long as the fence is tall. A 4 ft post for a 4 ft fence leaves nothing in the ground: about a third of the post should be buried.
• Spacing line posts more than 10 ft apart. The Home Depot guide sets 10 ft as the limit; the calculator starts from 8 ft.