Figure My Build

Fence Material Calculator

Enter the fence length and style. We split it into even sections, count the posts and rails, then work out pickets from their actual width and gap, not a guess per foot.

Diagram of a fence run showing posts at even spacing, with rails and pickets between them
A fence run is posts at even spacing, with rails and pickets between them.

Your buy-list

Enter your measurements

How fence materials are calculated

Posts: wood fence posts are spaced 6–8 ft apart. 8 ft is the standard maximum before rails start to sag. The calculator divides your fence into even sections no wider than your chosen spacing (a 100 ft fence at 8 ft spacing becomes 13 sections of 7.7 ft), and posts = sections + 1.

Rails: each section takes 2 rails on a fence up to about 5 ft tall, or 3 on a standard 6 ft privacy fence. Rails = sections × rails per section; buy them at 8 ft and cut to the actual section length.

Pickets: each picket covers its width plus the gap you leave. A standard 5.5 in picket with a 1/2 in gap covers 6 in, i.e. two pickets per foot. Pickets = fence length ÷ coverage, plus a waste allowance for warped or split boards. Setting the posts in concrete? The Post Hole Calculator turns the post count into bags.

Worked examples

100 ft privacy fence, 6 ft tall

8 ft max spacing → 13 sections; 3 rails per section; 5.5 in pickets, 1/2 in gap, 5% waste.

Buy 14 posts, 39 rails, 210 pickets

60 ft fence, 3.5 in pickets

6 ft spacing → 10 sections; 2 rails; 1/4 in gap, 5% waste.

Buy 11 posts, 20 rails, 202 pickets

48 ft garden fence

8 ft spacing → 6 sections; 2 rails; standard pickets, 5% waste.

Buy 7 posts, 12 rails, 101 pickets

Frequently asked questions

How many pickets do I need for a 100 ft fence?
With standard 5.5 in pickets and a 1/2 in gap, exactly 200 (two per foot), or 210 with a 5% allowance for bad boards. Dog-ear and gothic pickets are the same width math; only the top profile differs.
How far apart should fence posts be?
6 to 8 ft. Eight feet is the standard for a wood privacy fence with 2×4 rails; go to 6 ft in windy spots, soft soil, or with heavy pickets. Never stretch rails past 8 ft. The fence will wave within a season.
How many rails does a fence section need?
Two for fences up to ~5 ft, three for a 6 ft privacy fence. The middle rail stops long pickets bowing. Gates need their own frame. Order a few extra rails and pickets if you're building one.
What size posts should I buy?
4×4 posts for fences up to 6 ft (6×6 for gate posts and tall or windy runs), long enough for the fence height plus the hole depth. An 8 ft post suits a 6 ft fence with a 2 ft hole. Post length isn't counted here; match it to your frost depth.
Does this include gate materials or concrete?
No. Gates need hinges, a latch and diagonal bracing, and post concrete depends on hole size. Run your post count through the Post Hole Concrete Calculator for the bag count.

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Estimate disclaimer: results are planning estimates based on standard manufacturer yields and coverage figures. Site conditions, product choice and installation method change actual quantities. Verify before you buy, and follow local building code for structural work. This tool does not replace professional engineering advice.

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