Fence calculator
Posts, panels or rails and pickets, and the concrete to set the posts, for a new fence.
How it works
The fence is split into sections between posts. Sections = length ÷ panel width, rounded up; posts = sections + 1 for each straight run, plus one for each gate. For a picket fence we count rails per section and pickets along the whole length. Concrete for every post hole comes from our post hole calculator, with the post and gravel base taken off.
Worked examples
A 150 ft privacy fence in the US, built on site with 8 ft sections, three rails, 5.5 in pickets butted together, and 4×4 posts in 10 in holes 30 in deep with 6 in of gravel:
- 19 sections and 20 posts.
- 57 rails and 328 pickets.
- 34 × 80 lb bags of concrete, including 10% extra.
In the UK, a 20 m run of standard 6 ft (1.83 m) panels needs 11 panels and 12 posts, and 43 × 20 kg bags of concrete for 300 mm holes 600 mm deep with 100 mm square posts.
Panel widths by country
The calculator starts with a common panel width for your country: 8 ft sections in the US and Canada, 6 ft (1.83 m) panels in the UK and about 2.4 m panels in Australia. Measure the panels you're buying, and enter the post spacing centre to centre.
Before you dig
- Check where your boundary is, and whether you need permission for the height you want.
- Call your local utility locating service before digging post holes.
- Hole depth depends on the fence height, your soil and frost depth. A common rule is to bury about a third of the post's length.
Common questions
How many fence posts for 100 feet?
With 8 ft sections, 13 sections and 14 posts for one straight run. Each extra run or gate adds a post.
How many fence panels do I need?
Divide the fence length by the panel width and round up. 20 m of 1.83 m panels is 11 panels; the last one may need cutting down.
How many bags of concrete per fence post?
About two 80 lb bags for a 4×4 in a 10 in hole 30–36 in deep with gravel at the bottom. Use the calculator with your hole size for an exact count.
Reviewed by Alex Rowan, Editor. Last reviewed . How we calculate · Report a problem