How this fence lumber calculator works
For pickets, the calculator divides the fence run in inches by one picket width plus one gap, then rounds up to a whole piece. Rail length is fence length multiplied by the number of rail rows. Post count divides fence length by the maximum spacing, rounds up to the needed number of spans, and adds one end post.
This is a straight-run material estimate, not a construction plan. Gates, corners, changes in elevation, overlapping pickets, post embedment, rail joints, and local code requirements can change the final order.
Before ordering lumber
- Measure each straight fence section separately rather than treating a corner as one line.
- Use the installed face width of the picket, not only the nominal size on its label.
- Choose your actual gap before estimating the picket count.
- Check the rail lengths stocked by your supplier before deciding where joints will fall.
- Add your own allowance for cuts, defects, gates, and layout changes.
Need board-foot volume instead?
If your supplier prices lumber by volume rather than by piece, use the board foot calculator to total the thickness, width, length, and quantity of the lumber you plan to buy.
Fence lumber questions
Does this include a gate?
No. Measure gate framing and gate pickets as a separate material list because their dimensions and hardware vary.
Why does the post result include one extra post?
A run made of spans needs a post at both ends. For example, four spans need five posts.
Can I use this for a privacy fence?
Yes, if you enter the face width and planned gap for your pickets. The result is still an estimate and should be checked against your layout and local requirements.