Fence calculator
Estimate posts, rails, concrete, and pickets for wood, vinyl, or chain-link fences. Get an even post spacing layout and full materials list.
Inputs
Results
Total posts needed
Enter your measurements to see the result
posts
Adjusted post spacing
—
ft on centre
Post length (incl. burial)
—
ft per post
Horizontal rails
—
rails (2/section)
Concrete (80 lb bags)
—
bags
Pickets / boards
—
pcs (5.5" wide, privacy)
⚠ Posts = ⌈length ÷ spacing⌉ + 1. Burial depth = max(height ÷ 3, 2 ft). Rails per section: 3. Concrete: a 12″ hole filled to burial depth, minus the post, at 0.6 ft³ per 80 lb bag. Includes 10% waste on pickets. Always check local building codes for height limits and permit requirements.
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Frequently asked questions
How many fence posts do I need?
Divide your total fence length by your post spacing, round up, then add 1. For a 100 ft fence at 8 ft spacing: ⌈100 ÷ 8⌉ + 1 = 14 posts. Add 2 extra posts per gate opening.
How far apart should fence posts be?
8 feet on centre is the standard for most wood and vinyl fences. Use 6 ft spacing for fences over 6 ft tall or in high-wind areas. Chain-link fences typically use 10 ft spacing.
How deep should fence posts be buried?
Quikrete's post-setting instructions say to dig the hole 1/3 of the overall post length deep — which works out to half the above-ground height. A 6 ft fence needs 3 ft buried and a 9 ft post (cut from a 10 ft length). In cold climates, set posts below the local frost line (often 48 inches or more in northern states) to prevent frost heave, and check your local requirements.
How many bags of concrete do I need per fence post?
A 12-inch diameter hole 24 inches deep holds about 1.4 cubic feet of concrete around a 4×4 post. At 0.6 cubic feet per 80 lb bag, that's 3 bags per post. A 36-inch-deep hole (2.1 cubic feet) needs 4 bags. This calculator works it out from your fence height, filling the hole to the full burial depth.