Fence Calculator

Enter the total fence length and pick a standard panel width (6 or 8 ft). The calculator rounds the panels UP to cover the run, counts posts as one at the start of every panel plus one at the end — with an extra post for each gate — and totals the horizontal rails and the concrete for setting the posts.

Concrete uses 1.5 bags per post by default, a typical figure for a 60-lb bag and a standard post hole; deep holes, wide bores or gate posts need more, so adjust the bags-per-post input to your hole size. All counts are whole units, rounded up where a fraction would occur.

The formula

Panels = ceil(Fence length ÷ panel width); Posts = Panels + 1 + gates; Rails = Panels × rails per panel; Bags = ceil(Posts × bags per post)

Worked example

A 100 ft fence with 8 ft panels needs 13 panels, 15 posts (including one extra for the gate), 26 rails and 23 bags of concrete at 1.5 bags per post.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

How far apart should fence posts be?

Posts are spaced one panel width apart — 8 ft or 6 ft for pre-made panels. Spacing posts wider than the panel width leaves panels unsupported and sagging; in high-wind areas or for heavy gates, 6 ft spacing is safer.

How much concrete does one post need?

A typical 10–12 inch diameter hole about 2 ft deep takes roughly 1–2 bags of 60-lb concrete mix per post after the post displaces its volume. Gate and corner posts benefit from a bigger hole and an extra bag.

Does the last panel get cut?

Usually yes — runs rarely divide exactly by the panel width. This calculator rounds the panel count up; cut the final panel to fit rather than squeezing post spacing.

Category: Construction & Home calculators