About this calculator
Enter the length of fence in metres and the width of your panels (a standard panel is 1.83 m, or 6 ft), and get the number of panels and posts.
Add any gates and say whether the fence is a straight run (with posts at both ends) or a closed loop (a fully fenced plot where the ends meet).
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
10 m straight run
- Panels
- 6
- Posts
- 7
- Gates
- 0
- Space between posts
- 1.67 m (panels are cut to fit the last gap)
10 m of fence needs 6 panels and 7 posts.
Show the working
- Fence length less gates: 10 − 0 × 0.9 = 10 m.
- Panels = 10 ÷ 1.83 m, rounded up = 6.
- Posts: one at each end of every panel or gate, shared between neighbours: 6 panels + 0 gates = 6 gaps, so 6 + 1 = 7 posts. Add a spare panel for cuts and corners, and gravel boards if you use them.
10 m with one gate
- Panels
- 5
- Posts
- 7
- Gates
- 1
- Space between posts
- 1.82 m (panels are cut to fit the last gap)
10 m of fence needs 5 panels and 7 posts plus 1 gate.
Show the working
- Fence length less gates: 10 − 1 × 0.9 = 9.1 m.
- Panels = 9.1 ÷ 1.83 m, rounded up = 5.
- Posts: one at each end of every panel or gate, shared between neighbours: 5 panels + 1 gates = 6 gaps, so 6 + 1 = 7 posts. Add a spare panel for cuts and corners, and gravel boards if you use them.
A fully enclosed 20 m boundary
- Panels
- 11
- Posts
- 11
- Gates
- 0
- Space between posts
- 1.82 m (panels are cut to fit the last gap)
20 m of fence needs 11 panels and 11 posts.
Show the working
- Fence length less gates: 20 − 0 × 0.9 = 20 m.
- Panels = 20 ÷ 1.83 m, rounded up = 11.
- Posts: one at each end of every panel or gate, shared between neighbours: 11 panels + 0 gates = 11 gaps, so 11 posts (a closed loop has no end posts). Add a spare panel for cuts and corners, and gravel boards if you use them.
How it's worked out
The fence length less the gates is divided by the panel width and rounded up to give the panels. Each panel and gate fills a gap between two posts, so a straight run needs one more post than it has gaps. A closed loop has as many posts as gaps.
Practical points
- The last panel usually needs cutting to fit: the result shows the real spacing
- Corners and end posts may need to be heavier or braced
- Gravel boards, post caps and concrete or postcrete for each post are extra
- Posts are normally about 0.6 m longer than the panel height, for burying
Check before you buy
Measure the actual run along the line of the fence, allowing for slopes (stepped panels need more posts) and any trees or obstacles. Check boundary ownership and whether permission is needed for a fence over 2 m (1 m next to a highway).
Frequently asked questions
How many fence posts do I need?
One more than the number of panels and gates on a straight run; the same number on a closed loop.
How wide is a standard fence panel?
Usually 1.83 m (6 ft), sometimes 1.5 m or 1.8 m.
How do I allow for a gate?
Enter the number and width of gates: they take the place of panels and add a gap between posts.
Do I need a spare panel?
Often yes, for the cut at the end and for mistakes.
How tall can a fence be?
In England, up to 2 m at the back or sides, 1 m next to a road, without permission. Check your local rules.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.