Fence Calculator: Posts, Rails, Pickets & Concrete
Enter your fence length in feet, height and gates to see how many posts, rails, pickets and bags of concrete to buy for a wood fence.
Tool inputs stay in your browser · optional AI search sends your query
Good to know: Scope: the materials for a wood post-and-rail fence with pickets (a privacy fence or a spaced picket fence) in US units: posts, sections, rails, pickets and bags of concrete to set the posts, for up to 4 straight sides joined at the corners. It follows The Home Depot and Lowe’s guides: posts 6 to 8 feet apart (Lowe’s: 5 to 8 ft); a top and bottom rail for fences up to 4 feet tall and a third rail in the middle for taller fences; post holes about 3 times as wide as the post (12 inches for a 4×4); and about one third of the whole post in the ground (The Home Depot and QUIKRETE), so the depth in the ground is half the fence height unless you type your own. Actual lumber sizes come from the American Softwood Lumber Standard (PS 20): a 1×6 picket is 5-1/2 inches wide, a 4×4 post is 3-1/2 inches, a 6×6 is 5-1/2 inches. Concrete uses the QUIKRETE Concrete Mix bag yields (0.60 cu ft for an 80 lb bag) and fills the hole around the post up to the ground, so it is on the safe side. Each gate adds one post. Not included: chain link, vinyl, metal and board-on-board fences, gates and hardware, fasteners, gravel, slopes and stepped sections, frost-line depth, permits, HOA and city height rules, and labor. Everything stays in this browser tab; nothing is sent or saved. Independent ToolsKo estimate. Sources reviewed November 11, 2026.
How to use it (step by step)
- 1Measure each straight side of the fence in feet (or feet and inches) and type up to 4 sides. Choose “all the way around” only if the fence closes on itself.
- 2Enter the fence height, how far apart the posts will be (8 ft is common) and any gates with their width and side. Keep 5.5 inches for 1×6 pickets and 0 for a privacy fence with no gaps.
- 3Read the posts, rails, pickets and concrete bags to buy. Leave the depth box empty to use the one-third rule, then check your local frost line and call 811 before you dig.
Words to know
- Post spacing
- How far apart the posts stand, measured center to center. The space between two posts is one section; 6 to 8 feet is common.
- Rail
- The horizontal boards that run from post to post. The pickets are nailed or screwed to the rails.
- Picket
- The upright boards that make the face of the fence. Side by side they give privacy; with gaps they make a classic picket fence.
- Nominal vs actual size
- Lumber is sold by a rounded name. A “1×6” board is really 3/4 × 5-1/2 inches and a “4×4” post is 3-1/2 × 3-1/2 inches.
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Sources & methods
- The Home Depot: How to Build a Fence (posts 6–8 ft apart, hole 3 × post width, a third in the ground, 2 or 3 rails) ↗
- Lowe’s: Fence Installation Tips – Layout and Digging Post Holes (5–8 ft spacing, 12 in hole for a 4×4, 24 in typical depth) ↗
- QUIKRETE Concrete Mix No. 1101 product data sheet (bag yields; post hole 1/3 of post height, 3 × post width) ↗
- NIST / U.S. Department of Commerce: PS 20-25 American Softwood Lumber Standard, Table 3 (nominal and dressed sizes) ↗
References checked November 11, 2026. Read each tool’s scope and assumptions before relying on its result.