Fence Calculator
- Updated
- Imperial and metric
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Results
14 posts, 36 rails and 221 boards
Estimate for one continuous run with two ends. Each corner adds one post and usually a short section; a fence that closes on itself needs one post fewer.
How to use the fence calculator
- Pick the fence type: wood privacy (boards butted tight), wood picket (spaced pickets) or chain link.
- Measure the whole fence line, with every side added together and the gate openings included. Enter the number of corners, gates and the gate width.
- Set the post spacing. Wood fence posts are typically 6 to 8 ft (1.8–2.4 m) apart. Chain-link line posts are usually no more than 10 ft (3 m) apart.
- For wood, check the rails per section and the board width and gap. For chain link, enter the top rail stick length and fabric roll length printed on the products you plan to buy.
- Enter the hole size and depth to get the post concrete, and add prices if you want a cost.
How the fence calculation works
Sections = ⌈net length ÷ post spacing⌉ + corners
Posts = sections + 1 + gates
Rails = sections × rails per section
Boards or pickets = ⌈net length ÷ (width + gap)⌉ × (1 + waste)
Rails, boards and fabric only cover the net length, because gates are bought or built separately. Each corner starts a new straight run, which usually leaves one short section, so the calculator adds a section and a post per corner. Each gate opening adds the post on its far side. The result is an estimate for one continuous run with two ends. If your runs divide evenly by the post spacing you may need a post or two fewer, and a fence that closes on itself needs one post fewer.
For chain link, the posts are split by job and the fittings are counted from the post types:
Fabric rolls = ⌈net length ÷ roll length⌉ · Top rail sticks cover the net length, less the overlap at each joint
Tension bars, brace bands and rail ends = 2 + 2 × corners + 2 × gates
Tension bands (about one per foot of height on each tension bar) and fabric ties (about every 12 inches up each line post and every 24 inches along the top rail) are rules of thumb. Your fitting supplier may suggest different counts. Post concrete is the hole volume minus the post: (π × (hole diameter ÷ 2)² − post area) × hole depth, rounded up to whole bags per hole.
Worked example: a 150 ft privacy fence
A 6 ft privacy fence runs 150 ft around three sides of a yard, with 2 corners and one 4 ft gate. Posts are 8 ft apart, with 3 rails per section and 5.5 in boards butted tight. The net length is 146 ft, which gives 21 sections and 23 posts. You need 63 rails 8 ft long and 319 boards, or 335 with 5% waste. Setting 4×4 posts in 10 × 24 inch holes takes 0.92 ft³ of concrete each: 3 bags of 50 lb mix per hole, or 69 bags in total.
Posts, rails and boards by fence length
A straight 6 ft wood privacy fence with no gates: posts 8 ft apart, 3 rails per section, 5.5 in boards with no gap and 5% waste, 4×4 posts in 10 × 24 in holes.
| Fence length | Posts | Rails (8 ft) | Boards | 50 lb bags |
|---|---|---|---|---|
| 25 ft | 5 | 12 | 58 | 15 |
| 50 ft | 8 | 21 | 116 | 24 |
| 75 ft | 11 | 30 | 173 | 33 |
| 100 ft | 14 | 39 | 230 | 42 |
| 150 ft | 20 | 57 | 345 | 60 |
| 200 ft | 26 | 75 | 459 | 78 |
| 300 ft | 39 | 114 | 688 | 117 |
Chain-link parts by fence length
A straight 4 ft chain-link fence with no gates: line posts 10 ft apart, 21 ft top rail sticks with a 6 in overlap and 50 ft fabric rolls.
| Fence length | Terminal posts | Line posts | Top rail sticks | Fabric rolls |
|---|---|---|---|---|
| 50 ft | 2 | 4 | 3 | 1 |
| 100 ft | 2 | 9 | 5 | 2 |
| 150 ft | 2 | 14 | 8 | 3 |
| 200 ft | 2 | 19 | 10 | 4 |
| 300 ft | 2 | 29 | 15 | 6 |
Fence building tips
- Check the line and the rules first. Confirm where your property line is, and check local height limits, permits and any HOA rules before you order.
- Call before you dig. In the US, call 811 a few days ahead to have buried utility lines marked. Other countries have similar services.
- Size the holes. A common rule of thumb is a hole about three times the post width, dug one third to one half of the height above ground. In cold climates, go below the local frost line.
- Buy long enough posts. Post length is the height above ground plus the hole depth, so a 6 ft fence in 2 ft holes needs 8 ft posts.
- Give gates extra support. A swinging gate puts the most strain on its posts, so many builders use a larger post or a deeper hole there.
- Let the concrete set. Wait for the time on the bag before hanging gates or, for chain link, stretching the fabric against the terminal posts.
For holes with a gravel base or other sizes, use the post hole concrete calculator. Building a deck next? The deck calculator counts boards, joists and footings.
Frequently asked questions
How many fence posts do I need for 100 feet?
For a straight 100 ft run with posts 8 ft apart, you need 14 posts: 100 ÷ 8 = 12.5, rounded up to 13 sections, plus one post to close the last section. Each gate adds one more post, and each corner usually adds one. A chain-link fence with line posts 10 ft apart needs 11 posts: 2 terminal posts and 9 line posts.
How far apart should fence posts be?
Wood fence posts are typically 6 to 8 ft (1.8–2.4 m) apart, and 8 ft is common because it matches 8 ft rails. Chain-link line posts are usually no more than 10 ft (3 m) apart. Closer spacing makes a stiffer fence. Some panels, fabrics and local rules call for less, so check the product instructions and local requirements.
How many boards do I need for a 100 ft privacy fence?
With 5.5 in wide boards (a 1×6) butted tight, 100 ft is 1,200 in ÷ 5.5 = 218.2, so 219 boards, or 230 with 5% waste. A picket fence using the same boards with 2.5 in gaps needs 150 pickets, or 158 with waste.
How deep should fence posts be set?
A common rule of thumb is one third to one half of the post height above ground, so about 2 to 3 ft (60–90 cm) for a 6 ft fence. In cold climates the hole should go below the local frost line to resist frost heave, and gate and corner posts benefit from extra depth. Your local building department can confirm the frost depth and any fence rules.
How much concrete do I need per fence post?
A 10 in wide, 24 in deep hole around a 4×4 post takes about 0.92 cubic feet of concrete: three 50 lb bags or two 80 lb bags per post. Wider or deeper holes need more. The post hole concrete calculator handles other hole sizes and a gravel base.