Fence Section Calculator
Compute full pre-built fence panels, partial end cuts, gate deductions, and total posts needed across your property line.
Fence sections & panels
Enter your measurements and the result updates as you type.
Overview
Prefabricated panels make fence building fast, but property lines rarely divide neatly into exact 8-foot increments. This calculator determines full sections, exact cutoff lengths, and required posts.
Entering your total run and subtracting gates reveals how many factory panels to purchase and how long your custom trimmed section will be.
Common mistakes
- Purchasing panels before subtracting walk and driveway gate opening widths from the boundary run.
- Throwing away leftover panel cutoffs that could be used on short return runs or garden enclosures.
- Forgetting that every section requires one post plus a final terminal post to close the last bay.
- Attempting to install rigid panels on irregular rolling ground without stepping or racking.
Related calculators
- Fence Post Spacing Calculator Calculate exact on-center post spacing and section divisions to prevent short awkward end panels on any fence length.
- Fence perimeter calculator Get the total perimeter feet and the post sections that length implies for a rectangular yard, with the spacing math shown.
- Linear feet of fence calculator Add up every straight segment, gate span and slope run into one total linear footage for your fence material take-off.
- Fence Picket Spacing Calculator Calculate exact picket board counts and uniform spacing gaps between posts for clean shadowbox and picket fence panels.
Related reading
In-depth guides
Frequently asked questions
How many 8-foot panels do I need for 120 feet of fence?
Exactly 15 full 8-foot panels (120 / 8 = 15). You will need 16 posts to support 15 continuous sections.
What happens if my fence length does not divide evenly by 8 feet?
You purchase full panels for the main run, and on the last section, cut the rails and pickets of one panel to match the remaining partial distance.
Should gate openings be subtracted from the panel count?
Yes. A 4-foot walk gate and an 8-foot double gate remove 12 feet of run, reducing the number of standard privacy panels you need to buy.
Can you cut a prefabricated wood fence panel in half?
Yes. Cut the 2x4 backer rails between pickets using a circular saw, making sure to secure pickets with extra nails near the cut edge.
Can vinyl fence panels be cut down to custom widths?
Yes. Vinyl horizontal rails can be cut with a fine-tooth saw blade, but you will need a vinyl notching tool to re-crimp the locking tabs on the cut rail ends.
How many posts does a single panel need?
A single standalone panel needs two posts. For connected continuous runs, each additional section adds one post.
What is the standard width of pre-assembled fence panels?
Eight feet (96 inches) is the standard in wood and vinyl, while 6-foot (72 inches) widths are standard in metal ornamental and composite systems.
How do you transition fence panels across a corner?
A corner post accepts horizontal rails from two directions at a 90-degree angle. No extra panel is needed, just miter the rail ends to fit.