# Fence Calculator — Posts, Rails, Pickets & Concrete per Post > Free fence calculator: work out fence posts by role, rails, pickets or panels, and bags of concrete per post hole for privacy, spaced or panel fences. Metric and imperial, all client-side. Turn a run length and height into a material take-off — posts split by role, rails, pickets or panels, and concrete per post hole — in metric or imperial. - **HTML page:** https://siteometry.com/en/tools/fence-calculator - **Category:** [Framing & Carpentry](https://siteometry.com/en/tools/category/framing-carpentry) - **Figures live on the page:** tables, diagrams and worked figures the text refers to ("the table below") are drawn by the page and are not reproduced here. Each section below links to its anchor on the page. - **Runs in the browser:** Siteometry calculators need no account and send no input anywhere — every number below is computed on the visitor's own device. ## How to estimate a fence 1. **Choose units & currency** — Pick metric or imperial and your currency; every field follows. 2. **Set style & layout** — Choose privacy, spaced or panel, and whether the fence is an open run or a closed loop. 3. **Add runs & gates** — Enter each run's length and add a gate where you need one; the take-off updates live. 4. **Set infill & rails** — Set picket width and gap or panel size, and let rails auto-pick by height or override them. 5. **Set footings & concrete** — Choose post section, hole size, burial rule, gravel base and bag size to size the concrete. 6. **Read the take-off** — Read posts by role, rails, pickets or panels, concrete bags and the post length to buy. _On the page: https://siteometry.com/en/tools/fence-calculator#howto_ ## Fence materials overview A fence take-off is really four counts: posts split by where they sit (line, corner, end and gate), the rails or stringers that span between them, the pickets or pre-made panels that fill each bay, and the bags of concrete that set each post. This calculator turns a run length and a height into all four, in metric or imperial. Everything runs in your browser and nothing you type is uploaded. Post counts follow an explicit topology rule so an open run, an L-shape and a closed perimeter each come out right, and concrete is rounded up per hole the way you actually buy and mix it. _On the page: https://siteometry.com/en/tools/fence-calculator#fence-guide-intro_ ## How much fence do you need? Start from the total length of each run and the on-center post spacing — 8 ft (2.44 m) is the usual maximum for board and picket fences. The number of bays is the run length divided by the spacing, rounded up; the posts, rails and pickets all follow from the bays. The elevation below shows a 100 ft privacy run at 8 ft spacing: 13 bays give 14 posts on an open run, with three rails per bay and butted pickets filling each section. _On the page: https://siteometry.com/en/tools/fence-calculator#how-much-fence_ ## How this calculator works The tool keeps the math in a pure engine and the display in your chosen units. You describe the fence — style, layout, runs, gates, infill and footings — and it computes posts by role, rails, pickets or panels, concrete and the post length to buy, live as you type. Add a run for each straight section, mark a closed loop for a full enclosure, and drop in a gate where you need one. Gates take their own bay with no infill and re-tag the posts already at that bay, so nothing is double-counted. _On the page: https://siteometry.com/en/tools/fence-calculator#how-calculator-works_ ## Post & material formulas Quantities come from your run lengths and a few standard spacings. Post counts depend on the layout: an open run has two free ends and needs one more post than it has bays, while a closed loop shares every corner and needs exactly as many posts as bays. _On the page: https://siteometry.com/en/tools/fence-calculator#quantities-explained_ ## Concrete & footings Each post is set in a hole about three times the post width. Concrete fills the hole minus any gravel drainage base, minus the volume the post itself takes up. Bags are rounded up per hole and then summed, because you mix and pour whole bags at each post — rounding on the project total would leave some holes short. Burial depth and post length come from the same footing: a post is buried a third of its above-ground height (at least 24 in / 600 mm) or below your frost line, and the post you buy must cover the height, the burial and any gravel, rounded up to the next stock length. _On the page: https://siteometry.com/en/tools/fence-calculator#concrete-and-footings_ ## Privacy, spaced & panel Privacy fences butt pickets edge-to-edge for a solid screen, so the picket count is simply the bay width divided by the picket width. Spaced (picket) fences leave a gap between boards; the calculator evens that gap across each bay and reports the settled gap so the count looks right on site. Pre-made panel fences skip picket and rail math entirely: the spacing follows the panel width, and the panel count is the number of bays minus any gate bays. Concrete, burial and post length work the same way in all three styles. _On the page: https://siteometry.com/en/tools/fence-calculator#styles-compare_ ## Worked examples Two take-offs that show how the counts fall out of your inputs. Your dimensions will differ — these illustrate the method. _On the page: https://siteometry.com/en/tools/fence-calculator#examples_ ## Common mistakes The most common errors are adding a post per gate instead of re-tagging the ones already there, adding a corner post twice where two runs meet, and rounding concrete on the project total instead of per hole. All three throw the shopping list off. Forgetting the buried length when buying posts is the other big one — a 6 ft fence needs an 8 ft post once you add a 2 ft burial. _On the page: https://siteometry.com/en/tools/fence-calculator#mistakes_ ## Frequently asked questions Common questions about estimating fence materials, posts and concrete. ### How many fence posts do I need? Divide each run's length by the post spacing (usually 8 ft or 2.44 m) and round up to get the bays. An open run needs one more post than bays; a closed loop needs exactly as many posts as bays because every corner is shared. The calculator does this per run and splits the total into line, corner, end and gate posts. ### How many bags of concrete per fence post? It depends on the hole size and post width. For a common 4×4 post in a 10 in hole 2 ft deep, that is about three 50 lb bags. The tool computes the hole volume minus the post, divides by your bag yield, and rounds up per hole — then multiplies by the number of posts. ### How deep should fence posts be? A common rule is to bury about a third of the post's above-ground height, with a minimum of 24 in (600 mm). In cold climates set posts below the local frost line instead. The calculator supports both rules and always warns you to check your local code. ### How far apart should fence posts be? Board and picket fences are usually spaced up to 8 ft (2.44 m) on-center. Panel fences follow the panel width, most often 8 ft or 6 ft. You can set any spacing; the bays, posts and rails all recompute from it. ### What is the difference between privacy and spaced pickets? Privacy fences butt the pickets edge-to-edge for a solid screen (gap 0). Spaced (picket) fences leave a gap between boards; the calculator evens that gap across each bay and reports the settled gap so the count looks right on site. ### Do gates need extra posts? No extra posts are added. A gate takes its own bay with no pickets or rails, and the two posts on either side are re-tagged as gate posts — they are the boundary posts that were already there. Each gate also adds one hardware kit. ### What length posts should I buy? Add the fence height, the burial depth and any gravel base, then round up to the next stock length (8/10/12 ft or 2.4/3.0/3.6 m). A 6 ft fence buried 2 ft, for example, needs an 8 ft post. The tool shows the exact length to buy. ### How accurate is the estimate? It is a planning estimate, not an engineered design. Post spacing, rail counts and concrete volumes follow common conventions and add a waste allowance to cut materials. Use it to size a shopping list and check quotes, and confirm footings against local code. ### Does it work in metric and imperial? Both. Switch units at the top and every dimension, quantity and concrete volume converts — lengths in m or ft, picket and hole sizes in mm or in, and concrete in bags with metric or imperial yields. ### Is the calculator private? Yes. Every calculation runs in your browser. Nothing you enter is uploaded, and your project is saved only in your own browser's local storage. _On the page: https://siteometry.com/en/tools/fence-calculator#faq_ ## Related calculators - [Deck & Patio Cost Calculator](https://siteometry.com/en/tools/deck) - [Deck Railing & Baluster Spacing Calculator](https://siteometry.com/en/tools/deck-railing-calculator) - [Deck Joist & Beam Span Calculator](https://siteometry.com/en/tools/deck-joist-beam-span-calculator) - [Stair Calculator](https://siteometry.com/en/tools/stair-calculator)