Fence Calculator
Posts, rails, pickets or panels and concrete for any straight fence run — metric or imperial, with gates and an optional cost estimate.
Reviewed by the OmniCalc teamMethod verified 2026-07-01
Center to center
14 posts · 12 sections
14 posts, 12 sections- Posts
- 14
- Pickets
- 192
- Rails (3/section)
- 36
- Concrete bags
- 22
- Materials
- 14 posts · 12 sections
Planning estimate for a straight run — buy about 10% extra for cuts and waste. Corners and slopes need additional posts.
How the fence calculator works
Enter your total fence length, height and post spacing. The calculator subtracts your gate openings to get the fence line, divides by the spacing to count sections and posts, then works out rails, pickets or panels and the concrete needed to set every post.
sections = ceil((length − gates × gate width) ÷ post spacing)
posts = sections + 1 + gates
rails = sections × rails per section
pickets = ceil(fence line ÷ (picket width + gap))
concrete = posts × π × radius² × depth × 0.85
Rails default to two per section for fences under 6 ft (1.8 m) and three above, matching common building practice. You can override the rail count under “More options”.
Estimating tips
- Buy about 10% extra material to cover saw cuts, mistakes and warped boards.
- Add one post for every corner and every change of direction.
- On a slope, either step the panels (more posts) or rack them (more pickets).
- Set posts at least a third of their above-ground height into the ground for stability.
- Add prices under the cost section to turn the material list into a budget total.
Frequently asked questions
How many fence posts do I need?
Divide the fence line (total length minus gate openings) by your post spacing and round up to get the number of sections, then add one for the final post. Each gate needs one extra reinforced post. At 8 ft spacing a 100 ft run needs 13 sections and 14 posts.
How far apart should fence posts be?
Most wood and vinyl fences use 6 to 8 ft (1.8–2.4 m) post spacing. Closer spacing adds strength and cost; 8 ft is the common default for a standard privacy fence. Match the spacing to your panel width if you use pre-made panels.
How much concrete does each post need?
The calculator multiplies the hole volume (π × radius² × depth) by the post count and subtracts about 15% for the post itself. It then divides by the bag yield — roughly 0.6 ft³ for an 80 lb bag or 0.0125 m³ for a 25 kg bag — and rounds up.
How many pickets will I need?
In picket mode the tool divides the fence line by the picket width plus the gap between boards. For example, 100 ft (1,200 in) of 5.5-inch pickets with a 0.5-inch gap needs 200 pickets. Set the gap to 0 for a solid privacy fence.
Does this include corners and slopes?
No — it estimates a straight run. Add one post per corner and expect extra rails and pickets on sloped ground. Buy about 10% more material than the estimate to cover cuts and waste.
Estimates use standard construction conventions and are for planning only — confirm against your fence system’s instructions and local building codes. Last reviewed 2026-07-01.