Fence Calculator: 14 Panels for a 100 ft Fence Run

What does fence needed 14 panels and 15 posts mean?

It means fourteen panels, plus fifteen posts, fence a 100 ft run once cutting waste is allowed for. The run needs 12.5 panels exactly — 100 divided by 8 — and since panels do not split, the bare count is already 13; the 10% waste allowance takes 12.5 to 13.75 and the order rounds up to 14, which covers the short end section and the panel that arrives damaged. Posts are panels plus one: every panel needs a post at each end, and neighbours share, so fourteen panels stand on fifteen posts, one at each end of the run and one between every two panels.

Output · formula · meaning

Three things to check before you trust the number

First, check the panel width against your panels: 8 ft is the common width, but 6 ft panels are sold too, and a narrower panel raises the count for the same run — 100 ft takes 19 panels at 6 ft, not 14. Second, measure the run along the fence line, including any slope: a run that drops downhill is longer on the ground than on the plan, and the plan length under-orders. Third, remember the count is panels and posts only — it does not include rails if the panels are built on site, concrete for the post holes, gate hardware, or the gates themselves, which are separate lines on the same job, and a run that turns a corner needs a corner post the straight-run count does not add.

Worked example

100 ft long, 8 ft panels, 10% waste, 0 gates. Panelled length: 100 − 0 × 4 = 100 ft. Exact panels: 100 ÷ 8 = 12.5. With waste: 12.5 × 1.10 = 13.75, rounded up to 14 panels. Posts: 14 + 1 = 15. In practice that means ordering 14 panels and 15 posts, and expecting the last section to be a cut panel — keep the offcut, since it is the short section the far end needs. If the same run used 6 ft panels instead, the count would rise to 19 panels and 20 posts with waste, but the run fenced would be identical.

Every branch, checked

With a 120 ft long run instead of 100 ft, the exact count rises to 15 panels and the need to 17 panels with waste, plus 18 posts. With 6 ft panels, the exact count rises to 16.67 panels and the need to 19 panels with waste, plus 20 posts. With 0% waste, the exact count stays 12.5 panels and the need falls to 13 panels, plus 14 posts. With 2 gates, the panelled length falls to 92 ft and the need to 13 panels with waste, plus 14 posts. Length, panel width, waste and gates each move the count on their own, so a wrong panel width is as costly as a wrong measurement.

The reverses, worked backwards

The length behind 14 panels is 100 ft: at 80 ft the need is 11 panels and 12 posts; at 120 ft it is 17 panels and 18 posts. The panel width behind 14 panels is 8 ft: at 6 ft the need is 19 panels and 20 posts; at 10 ft it is 11 panels and 12 posts. The waste behind 14 panels is 10%: at 0% the need is 13 panels and 14 posts; at 20% it is 15 panels and 16 posts. Each reverse moves one input and holds the rest, so the step is exactly one dimension or one waste change.

What the defaults assume

The defaults assume a straight 100 ft run, 8 ft panels, 10% cutting and breakage waste, and no gates. They do not assume a corner post, a slope that lengthens the run, rails built on site, post-hole concrete, or gate hardware — a run that turns needs its corner post added, and gates are bought as units, not counted as panels.

Who uses this

• A homeowner fencing a garden boundary: the 14-panel, 15-post order settles the merchant call before the first hole is dug.
• A DIY builder replacing a fence section: the same maths on the section length alone gives the panels, not a whole run.
• A contractor quoting a fence: length, panels, posts — the quote follows the same four steps, and the waste line shows the client why.
• A landlord securing a rental’s garden: the boundary length off the plot plan, divided by panel width, gives the fence line on the refresh budget.

Accuracy & limitations

The arithmetic is exact for the inputs entered; the judgement is the panel width and the waste allowance. Real runs slope, turn corners and end in short sections, and a run measured on the plan can be shorter than the run on the ground — so treat 14 panels and 15 posts as the planning order for a straight 100 ft run at 8 ft panels, and add a corner post for every turn. If the panels are built on site rather than bought whole, count rails and boards separately.

Cite this calculator

Bright Side Kit, “Fence Calculator: 14 Panels for a 100 ft Fence Run”, https://brightoolbox.com/fence-calculator/, accessed 3 November 2026. Students and researchers: cite the calculator name, the page URL and the date you used it, and quote the defaults (100 ft run, 8 ft panels, 10% waste, 0 gates) so the 14-panel result can be checked.

Frequently asked questions