Fence Picket Calculator
Buying the right number of pickets saves you a trip back to the lumber yard (and the temptation to skip the last 10 feet). Enter your fence dimensions, picket size, and gap preference, and this calculator gives you exact picket, post, and rail counts with a waste factor built in.
The picket count formula divides the total fence length (in inches) by the combined width of one picket plus one gap. For a privacy fence with zero gap and 3.5-inch pickets, that works out to about 3.43 pickets per linear foot, or roughly 27 pickets per 8-foot section.
Posts are spaced every 6 to 8 feet on center. Eight-foot spacing is the most common because standard lumber comes in 8-foot lengths, so your 2x4 rails fit perfectly between posts without cutting. If you are building in a windy area or using heavier pickets, drop to 6-foot spacing for extra strength.
The waste factor accounts for knots, splits, warped boards, and cutting errors. A 10% waste factor is standard for fence projects. If you are using pre-stained or premium pickets that come in consistent quality, you can drop to 5%. For rough-sawn cedar with more natural variation, go with 15%.