Fence Calculator – How Many Pickets & Posts Do I Need?
Enter your fence length and picket spacing to get exact picket, post and rail counts — plus a cost estimate.
How the fence math works
Pickets are spaced evenly along the run, with one gap between every two pickets. For a picket width of 5.5 in and a 0.5 in gap, each picket-plus-gap uses 6 in of fence length, so a 100 ft run needs about 201 pickets (200 + a starter board for the far end).
Pickets ≈ length (ft) × 12 ÷ (picket width + gap), rounded up
Posts are placed every 6–10 ft (8 ft is standard). A 100 ft fence with 8 ft spacing needs 14 posts (13 sections). Rails run between posts: a 6 ft fence usually takes 3 rails per section, a 4 ft fence takes 2.
Pickets and posts for common fence sizes
| Fence length | Pickets (5.5 in + 0.5 in gap) | Posts (8 ft spacing) | Rails (3 per section) |
|---|---|---|---|
| 50 ft | 101 | 8 | 21 |
| 100 ft | 201 | 14 | 39 |
| 150 ft | 301 | 20 | 57 |
| 200 ft | 401 | 26 | 75 |
Buying tips
- Add 5–10% for waste — warped boards, bad cuts and mistakes.
- Pressure-treated posts resist rot; set them in concrete below the frost line in cold climates.
- Keep the leftover can of stain labeled for touch-ups after a year.
Related guides
Fence calculator FAQ
How many pickets are in a 100 ft fence?
With 5.5 in pickets and a 0.5 in gap, a 100 ft (1,200 in) run needs about 201 pickets. Use the calculator above for your exact width and gap.
How far apart should fence posts be?
8 ft is the standard spacing for wood privacy fences. Windy areas or gates should use 6 ft; never exceed 10 ft between posts.
Do I need 2 or 3 rails?
Use 3 rails on a 6 ft fence for strength and to keep pickets from sagging. A shorter 4 ft fence usually needs only 2 rails.
Planning another project?
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