How Far Apart Should Fence Posts Be?
Spacing by fence type
| Fence | Spacing | Why |
|---|---|---|
| Pre-made panels | Panel width exactly | Fixed by the product — usually 6 or 8 ft; measure a panel, do not assume |
| 4 ft picket, built on site | 8 ft | Light, low wind load |
| 6 ft privacy, built on site | 6–8 ft | 8 ft works with 2x4 rails; 6 ft sags less over time |
| 6 ft privacy, windy or exposed | 6 ft | A solid fence is a sail — closer posts share the load |
| Ranch rail, split rail | 8–10 ft | Often fixed by rail length |
| Chain link, residential | up to 10 ft | Fabric spans well; check the manufacturer's figure |
| Wire, agricultural | 10–16 ft | With tension and bracing at corners |
Why 8 ft is the usual ceiling
Two reasons, and both are about the rails rather than the posts. A 2x4 rail spanning more than 8 ft sags visibly under its own weight plus the pickets hung on it. And lumber comes in even lengths — 8, 10, 12, 16 ft — so 8 ft bays let you cut rails with no waste and let a 16 ft board make exactly two.
Go closer than 8 ft when the load goes up:
- Height. Wind load scales with the area of the fence. A 6 ft solid fence catches half again more wind than a 4 ft one over the same length.
- Solidity. A board-on-board or tongue-and-groove privacy fence gives wind nowhere to go. A picket fence with 1 in gaps bleeds off a surprising amount of pressure.
- Exposure. A fence at the top of a slope or across open ground takes far more than one sheltered between two houses.
- Soil. Sandy or soft ground holds a post less firmly, so more posts share the load.
Spread the spacing evenly — do not leave a stub bay
A 100 ft fence at 8 ft nominal spacing is 12.5 bays. Twelve 8 ft bays plus one 4 ft bay looks like a mistake, and the short bay is exactly where the eye goes. Divide instead: 13 bays at 7.69 ft each, all identical.
This is what the fence calculator does — it takes the ceiling of length divided by spacing, then reports the actual spacing so you can lay out to that figure. If the actual spacing comes out awkward, adjust the target until it lands somewhere clean.
Post count, and the one people get wrong
A fence needs one more post than it has sections, because both ends need one. Thirteen sections is fourteen posts. Then add a post per gate opening, and remember that gate and corner posts should be heavier and deeper than line posts because they carry concentrated load.
Before you dig
Enter the run length and post spacing to get posts, sections, rails and pickets — plus the concrete needed to set every post, which is usually the item people underestimate.
Frequently asked questions
How far apart should fence posts be?
Eight feet is the usual maximum for picket and rail fences built on site, because a 2x4 rail sags beyond that span. Use 6 feet for 6 foot privacy fences, exposed or windy sites, and soft soil. Panel fences are fixed by the panel width.
Can fence posts be 10 feet apart?
For chain link and agricultural wire, often yes. For a wooden fence with horizontal rails, no — the rails sag and the pickets follow. Ranch rail fences can reach 10 feet because the rails are heavier and there is no infill weight.
How many posts for a 100 ft fence?
At 8 foot spacing, 13 sections and 14 posts, since a fence always needs one more post than sections. Add one per gate. At 6 foot spacing it is 17 sections and 18 posts.
Should I space posts evenly or use full 8 ft bays?
Evenly. Dividing 100 feet into 13 identical 7.69 foot bays looks deliberate, while 12 full bays plus a 4 foot stub looks like a mistake and draws the eye straight to it.