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Calculation details
Planning estimate only. Verify dimensions, waste, coverage, product specifications, and local requirements before purchasing materials.
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What does this calculator estimate?
Fence calculator: estimate posts, rails, pickets, and concrete needed for your fence from length, height, and spacing. Free, editable rates, no signup.
How this calculator works
Frequently asked questions
How does this fence calculator determine the materials I need?
The fence calculator uses your inputted fence length, height, and post spacing to estimate the number of rails, pickets, and posts required, all processed locally in your browser without saving any data.
Do I need to create an account or sign up to use the fence calculator?
No, this is a completely no-signup tool. You can use the fence calculator directly in your browser, and your measurements are never stored or sent to a server.
Will my fence measurements be saved or shared when using the calculator?
No, because the fence calculator runs entirely in your browser, your data stays private on your device and is not saved or shared with anyone.
Cite this tool
BoringToolsKit. “Fence Material Calculator.” boringtoolskit.com/fence-material-calculator/. Free to reference in articles, syllabi, and answer posts with a link.
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Worked example: a 100-foot run with three rails
Suppose you are fencing a straight 100-foot backyard run with 8-foot sections, 3 rails per section, and 5.5-inch pickets. The calculator divides length by section width and rounds up: 100 / 8 = 12.5, so sections = 13. Post count is always sections + 1, which comes to 14 posts. That rounding-up rule is what keeps you legal: at exactly 12.5 sections you cannot buy half a panel, and stretching panels to 7.7 feet each is how fences end up wavy and off-spec.
Rails are simpler: 13 sections times 3 rails = 39 rails. Since most 6-foot wood privacy fences use two rails and many stockade styles use three, that single multiplier is where most of the lumber estimate swings. Going from 2 to 3 rails on this run jumps the rail order from 26 to 39, roughly a 50 percent change in that line item alone.
Pickets use inches, not feet: 100 feet x 12 = 1,200 inches, divided by a 5.5-inch picket = 218.18, which rounds up to 219 pickets. Notice what narrower pickets do. At 3.5 inches (the common 1x4 spacing choice) the same run needs 343 pickets, a 57 percent increase. The two inputs that most change your material bill are picket width and rail count, not section length, which mostly just shifts where the posts land.
Boundary cases the calculator will not save you from
The calculator protects against two classic divide-by-zero crashes but the results are still nonsense inputs. Enter 0 for section width and it clamps the divisor to 0.1 feet, so a 100-foot run reports 1,000 sections and 1,001 posts. The math runs; the estimate is useless. Negative values behave the same way, because Math.max(0.1, -8) still yields 0.1. Anything under 1 foot per section or under 1 inch per picket deserves a manual sanity check before you order materials.
The section count is also sensitive to fence length itself. A 99.9-foot run with 8-foot sections still produces 13 sections (12.49 rounds up), so 1 percent of length can add a whole panel and post. Real fence lines rarely break exactly on a section boundary: plan the leftover partial section as a cut panel on the end farthest from the gate, not in the middle.
What the formula ignores entirely: corner posts, end posts vs. line posts (they differ in cost and hardware), gate frames and hinges, post caps, concrete per post (typically 1 to 2 bags per post depending on frost depth), and terrain slope, which lengthens actual material needs on a hill. A straight 100-foot flat run with no gate is the ideal case. Add roughly 10 percent waste on pickets and lumber as a working buffer, and budget gate hardware separately, since the picket count here assumes no opening in the run.