Fence calculator
Enter the length and height of your fence and get the posts, rails, boards, concrete and fixings to buy. Works in feet or metres.
Shopping list
Enter what your store charges for one of each item. Prices stay in your browser.
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How to use the calculator
- Measure the full line of the fence, including the gate openings.
- Count the corners, where the fence changes direction.
- Pick the height, the distance between posts and the board width you plan to buy.
- Set the gap to 0 for a solid privacy fence, or to the space you want between pickets.
- Print the list or copy it to your phone before you go to the store.
How the numbers are worked out
Posts
Posts = sections + 1, plus 1 for each gate and each corner
A 100 ft fence with one 4 ft gate has 96 ft of fence. At 8 ft between posts that is 12 sections and 13 posts. The gate adds one post and two corners add two more, so the list shows 16.
Rails
Fences up to 5 ft (1.5 m) tall use 2 rails per section. Taller fences use 3, so the boards do not warp.
Fence boards
100 ft is 1,200 in. With 5½ in boards and no gap, 1,200 ÷ 5.5 = 218.2, so 219 boards. Adding 5% for splits gives 230.
Concrete
A hole 10 in wide and 30 in deep around a 4×4 post takes 1.15 cubic feet of concrete, which is about 3 bags of 50 lb fast-setting mix.
Common questions
How many fence posts do I need for 100 feet of fence?
With posts 8 ft apart, a straight 100 ft fence needs 13 sections and 14 posts. Add one post for each gate and one for each corner.
How far apart should fence posts be?
8 ft (2.4 m) is the usual maximum for a wooden fence, because rails are sold in that length. Use 6 ft (1.8 m) in windy places or for a heavy fence.
How deep should a fence post hole be?
Bury about one third of the post. For a 6 ft fence that is a hole 24 to 30 in deep. Where the ground freezes, the hole should go below the frost line.
How many bags of concrete do I need per fence post?
A 4×4 post in a hole 10 in wide and 30 in deep takes about 3 bags of 50 lb fast-setting concrete. A wider or deeper hole takes more; the calculator works it out from your hole size.
How many pickets do I need per foot of fence?
With 5½ in boards and no gap, you need 2.2 boards per foot. With 3½ in pickets and a 2 in gap, you need 2.2 pickets per foot as well, because each picket and its gap also cover 5½ in.
What the list leaves out
- Gravel for drainage at the bottom of each hole.
- Stain, paint or sealer.
- Kickboards along the bottom of the fence.
- Extra posts and stepped sections on sloping ground.