Planning a fence and not sure how many posts to order? This fence calculator works out posts, panels, rail length, and post-hole concrete from your run length and post spacing, so you order the right amount instead of making a second trip to the yard.

Pick a layout to load sensible starting dimensions, choose your fence material, and the numbers update as you type.

Why people use this tool

• Exact post count, not a rough guess: get the precise number of posts your run needs, including extra posts for each gate.
• Works for any layout: a single straight run, a full rectangular yard perimeter, or a custom total length if you already know it.
• Adjusts to your material: wood picket, wood privacy, chain link, vinyl, and wrought iron all load different default post spacing and rail counts, since they’re built differently.
• Concrete for post holes included: enter your hole diameter and depth and get the number of concrete bags to buy, not just the fence materials.
• Optional cost breakdown: add your fencing, post, and concrete prices to see a full estimate before ordering.

How post count actually works

A fence isn’t just total length divided by spacing. This calculator first subtracts the width of any gates from your total run, since gates don’t need regular in-line posts along their span. What’s left is divided by your post spacing and rounded up, plus one extra post to close off a straight run (a closed loop, like a rectangular yard, doesn’t need that extra post since it wraps back to the start). Each gate then adds two more posts of its own, since gate posts are separate from the regular spacing run.

For example, a 20m straight run with 2.4m spacing and no gates needs 9 posts (20 ÷ 2.4 = 8.33, rounded up to 9, plus 1 to close the run). Add one 1m gate and that becomes 8 posts along the reduced 19m run, plus 2 dedicated gate posts, for 10 posts total.

Panels, the sections of fence between posts, follow directly from the post count: one fewer panel than posts for a straight run, or equal to the post count for a closed loop around a yard.

Choosing spacing and rails by material

Post spacing depends heavily on what you’re building. Wood picket and vinyl fences typically use posts every 2.4m (8ft), chain link usually stretches to 3m (10ft) between posts since the fabric itself provides tension, and wrought iron or aluminum panels are often pre-made in fixed widths closer to 1.8m (6ft). Picking the right material preset loads a sensible starting spacing, which you can still adjust if your panels or local frost line call for something different.

Rails, the horizontal framing members a fence hangs from, also vary by build. A basic picket fence usually needs 2 rails (top and bottom), a privacy fence with taller panels often uses 3 for extra rigidity, and chain link relies mostly on a single top rail with the fabric tensioned below it. This calculator multiplies your fenced run by the rails-per-panel figure to give a total linear rail length, useful for ordering rail stock regardless of exactly how it gets cut into sections.

Concrete for post holes

Loose or wobbly posts are one of the most common fence complaints, and it almost always comes down to under-sized post holes. This calculator treats each hole as a cylinder, using your diameter and depth to work out the volume, multiplies by your total post count, and converts that to quick-set concrete bags using a standard bag yield.

A typical residential fence post sits in a hole about 30cm (12in) across and 60cm (24in) deep, roughly a third of the post’s above-ground height buried below grade for stability, though local frost depth requirements can call for deeper holes in colder climates.

Estimating cost

Toggle Estimate Cost and enter what you pay per linear meter or foot of fencing material, per post, and per bag of concrete. The calculator multiplies each by the quantities above and shows a line-by-line breakdown next to the total, so you can see how much of the budget is fencing versus posts versus concrete before you order.

If you’re also pouring a patio or footing nearby, the Concrete Calculator handles that separately. For an irregularly shaped yard, the Area Calculator can help work out the perimeter first, and the Length Converter is handy for converting a supplier’s spec sheet between metric and imperial.

These figures are estimates for planning purposes. Local zoning rules often set minimum post depths, maximum fence heights, and setback requirements from property lines, so confirm the details with your municipality or a licensed contractor before you dig.