Walk a real job with me, and the numbers start to make sense. Picture a straight 100 ft privacy fence along the back of a yard, with one walk-through gate near the driveway. We will lay it out post by post, board by board, and stop at the point where you know what to load onto the truck.
Lay the posts first
Posts go in before any board touches them. On well-drained soil, space them 8 ft on center. For a 100 ft run that works out to about 14 posts, counting the one at each end. Mark the line with stakes and twine, dig each hole below frost depth, and set the post in concrete. Gate posts deserve extra bracing because the hardware pulls on them every time someone opens or closes the gate.
If the yard slopes, do not bend the fence to follow the ground. Step the posts so each bay stays level, and cut the bottom of the boards to follow the slope on site.
Count the boards
For a privacy fence you butt 6 in boards edge to edge with no gap. Run a string line along the rails so the tops stay straight. Across 100 ft you are laying roughly 200 boards. That is the number that matters when you call the lumberyard, because boards are sold individually, not by the panel.
Leave a 1/4 in gap only if you want wind to pass through or you expect the wood to move a lot. Gaps drop the board count a little, but they also break the privacy look.
Knock out the gate
A 4 ft walk gate is not covered by boards; it is an opening. Subtract about 4 ft of board run from the 100 ft before you count. On this job that means roughly 8 fewer boards, plus the gate itself, the latch, and two heavy gate posts on either side. Order gate hardware separately, because the calculator never prices it.
Boards versus panels
Boards give you a flexible fence. You cut them on site, follow slopes, and fix mistakes one board at a time. Panels come factory-built in 8 ft widths, so the post spacing is locked to that module and the fence only looks right on flat ground. Panels are faster to stand up; boards look better and cost less per foot on tricky yards.
What still goes on the list
The calculator gives you boards and posts only. Plan for two or three horizontal rails per bay, one to two bags of concrete per post, post caps, and a box of screws or nails. Gates get their own hinge set and latch. Add a couple of spare boards for cuts, because warped stock happens.
Worked example
Straight 100 ft line, 6 in boards, 8 ft posts, one 4 ft gate: about 192 boards and 14 posts. Round the board count up at the counter, never down.
Fence Calculator
Walk a 100 ft privacy fence from post layout to gate openings, and land on about 200 boards and 14 posts for the run.
How to use
- Measure the total lineal feet of fence you want to build
- Pick your board width, usually 6 in for privacy
- Set post spacing, 8 ft on center for most soil
- Count each gate opening and subtract its board run
- Read the board and post count before you order
Supported formats and limits
- Estimate only, add a few boards for miscuts and warped stock
- Rails, concrete, post caps and gate hardware are not counted
- Works for straight runs; sloped yards need longer boards and stepped posts
Examples
100 ft privacy fence with 6 in boards, 8 ft posts, one 4 ft gate lands near 192 boards and 14 posts.Common errors
- Fence length must be a positive number of feet
- Board width and post spacing cannot be zero or negative
- Gate count must be a whole number of openings
Privacy and browser support
All calculations run locally in your browser. No measurements are uploaded.
FAQ
How do I count boards for a privacy fence?
Lay the 6 in boards edge to edge across the run. A 100 ft straight line takes about 200 boards when you butt them tight. If you leave gaps for wind, the count drops.
How far apart do the posts go?
8 ft on center is the standard for a wood privacy fence. On soft, wet, or sloped ground, drop to 6 ft so the rails do not sag.
How does a gate change the board count?
A gate opening is a hole in the board line. Each 4 ft gate removes roughly the boards that would cover that 4 ft of run, so subtract about 8 boards per gate before you buy.
Should I buy boards or preassembled panels?
Boards let you follow sloped ground and cut on site. Panels are faster on flat yards but lock you to an 8 ft module. Panels usually come in 8 ft widths, so post spacing matches the panel instead of being chosen freely.
How many posts does 100 ft need?
At 8 ft spacing you land near 14 posts for a straight run, counting one at each end. Corners, gate posts, and bays add a few more.
Do I need concrete under every post?
Set each post in concrete in most frost zones, about one to two bags per post. The calculator counts posts only, not the bag count.