Fence Calculator
Turn a fence line into a lumber list: posts, pickets, rails, and the concrete to set them — for privacy or picket styles, before you price a single board.
Add up all runs; measure along the ground.
Standard dog-ear pickets are 5.5″ wide.
Classic pickets are 3.5″ (1x4) wide.
2–2.5″ is typical; match the gap to the picket for a classic look.
Counted at 4 ft wide each; gate hardware and boards are extra.
Each corner adds a post.
You need
Enter fence length
| Material | Amount |
|---|---|
| Posts (4x4) | — |
| Rails (2x4, 8 ft) | — |
| Concrete, 80 lb bags | — |
| Concrete, 60 lb bags | — |
Treated dog-ear pickets commonly run $3–$7 each.
How to Calculate Fence Materials
A wood fence is four counts — posts, rails, pickets, and concrete — all driven by length, height, and post spacing:
- Posts: divide the length by post spacing, round up, and add one for the end. Add a post per corner; gates hang on the posts you already counted.
- Rails: 2 per section for 4 ft fences, 3 for 6 ft, 4 for 8 ft.
- Pickets: fence length in inches ÷ (picket width + gap). Butted privacy fences use a 0 gap.
- Concrete: about 1½ bags of 80 lb mix per post for a 24″ hole — deeper holes for taller fences take 2.
Fence formulas
Posts = ceil(length ÷ spacing) + 1 + corners
Pickets = (length − gate widths) in inches ÷ (picket width + gap)
Rails = sections × rails per section
Worked example — 100 ft privacy fence, 6 ft tall, 2 corners, 1 gate: 13 sections → 16 posts, 39 rails, and 96 ft of picketed run ÷ 5.5″ = 210 pickets, set with about 23 bags of 80 lb concrete.
Materials for Common Fence Lengths
6 ft privacy fence, 8 ft post spacing, one 4 ft gate, two corners:
| Fence length | Posts | Rails | Pickets | 80 lb bags |
|---|---|---|---|---|
| 50 ft | 10 | 21 | 101 | 15 |
| 100 ft | 16 | 39 | 210 | 23 |
| 150 ft | 22 | 57 | 319 | 32 |
| 200 ft | 28 | 75 | 428 | 40 |
| 300 ft | 41 | 114 | 646 | 59 |
Tips Before You Build
- Call 811 before digging. Free utility marking, required in most states, and it takes a couple of days — schedule it first.
- Check property lines and permits. Fence height limits (often 6 ft back yard, 3–4 ft front) and setbacks are local rules; HOAs add more.
- Set posts below the frost line and crown the concrete so water sheds away from the wood.
- Buy 5–10% extra pickets. Some arrive warped or split; culls make great stakes and rot boards.
- Keep pickets 2″ off the ground — end-grain ground contact is the fastest way to rot a fence.
Frequently Asked Questions
How many posts for 100 feet of fence?
14 for a straight run at 8 ft spacing (13 sections + 1 end post); 18 at 6 ft spacing. Add one per corner.
How many pickets per foot?
About 2.2 per linear foot with standard 5.5″ pickets butted tight; about 1.6 per foot spaced with a 2″ gap.
How many rails for a 6 ft privacy fence?
Three per section — top, middle, bottom. Two for 4 ft fences, four for 8 ft.
How much concrete per post?
About 1½ bags of 80 lb mix for a 10″ × 24″ hole; 2 bags for the deeper holes taller fences need. Our concrete calculator has a dedicated post-hole mode.
How deep should posts be set?
One-third of post length, minimum 24″, below frost line. A 6 ft fence takes 9 ft posts set ~3 ft deep.
Should pickets touch the ground?
No — keep 2″ of clearance, or run a sacrificial rot board at grade.
References
- Common Ground Alliance — Call 811 before you dig: call811.com
- American Wood Protection Association — treated wood use guidance: awpa.com
- University of Georgia Extension — fence planning and construction: extension.uga.edu