How it is calculated
Gate width is subtracted from the fence length. The rest divided by the post spacing gives the number of bays; there is one more post than bays plus one per gate. Pickets are counted by width plus gap. Fences taller than about 5 ft 11 in get three rails per bay, lower ones two.
Bays = (length − gates) ÷ post spacing, rounded upPosts = bays + 1 + number of gatesPickets = (length − gates) ÷ (picket width + gap)Example
A 100 ft wood privacy fence 6 ft tall with a 4 ft gate and posts 8 ft on center needs 210 pickets 5.5 in wide, 14 posts 8 ft long, about 300 linear ft of 2×4 rails, roughly 1,260 fasteners and 0.57 cubic yards of concrete.
Tips from practice
- Set posts about one-third of their length in the ground, below the frost line in cold climates.
- Call 811 before you dig to have utility lines marked.
- Check HOA rules and local limits on fence height, often 6 ft in back yards.
Questions and answers
How far apart should fence posts be?
Usually 6–8 ft on center for wood privacy fences; 8 ft matches standard rails and panels.
How much concrete per fence post?
A 10 in hole 2 ft deep takes about 1.1 cu ft, roughly three 50 lb bags of fast-setting concrete.
How many pickets for 100 ft of fence?
With 5.5 in pickets and no gaps, about 218 pickets before subtracting gates.
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