How to use the fence calculator
- Measure the total run of fence.
- Choose post spacing and count gates and extra corner/end posts.
- Enter picket width and gap.
- Set hole size and depth to your local requirements.
Formula
Sections = ⌈length ÷ spacing⌉; posts = sections + 1 + gates + extras; rails = sections × rails per section; pickets = ⌈length (in) ÷ (picket width + gap)⌉; concrete per hole = π r² × depth − post cross-section × depth.
Worked example
100 ft at 8 ft spacing: 13 sections → 14 posts + 1 gate + 2 extras = 17 posts, 26 rails, 219 pickets (5½ in, no gap), and about 1.15 ft³ of concrete per 10 × 30 in hole — 33 bags of 80 lb for all 17 posts.
Tips for using the fence calculator
- Confirm your property line before setting posts; a survey costs less than moving a fence.
- Set posts below the frost line in cold climates so they do not heave.
- Call 811 before digging to have buried utility lines marked.

Fence Calculator FAQs
How far apart should fence posts be?
6–8 ft for most wood fences; vinyl and metal panels set their own spacing.
How deep should fence posts be?
A common rule is about one-third of the post length in the ground, and below the local frost depth where frost heave is a concern.
Do I need a permit for a fence?
Many towns regulate height and placement. In NYC, residential fence installers fall under the DCWP home improvement contractor license. See our fence guide.
