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How the Fence Calculator Works
Our fence calculator uses industry-standard formulas to estimate the materials you need. It divides your total linear footage by the post spacing to determine the number of posts, then calculates rails and pickets based on the fence style you choose.
Understanding Fence Styles
Privacy fences use 6-foot-tall boards placed side by side with no gaps. They typically need 3 horizontal rails per section and about 16 pickets per 8-foot span. Picket fences are shorter (4 feet) with spaced boards, requiring fewer pickets per section. Split rail fences are the most economical, using only horizontal rails between posts with no pickets at all.
Post Hole Tips
Each fence post should be set in a hole roughly 3 times the post width and one-third the total post length deep. For a 6-foot privacy fence, that means setting 8-foot posts about 24-30 inches deep. One 50-lb bag of quick-set concrete is typically enough per post hole in firm soil; use two bags per hole in sandy or loose ground.
When to Add Extra Materials
- Add 10% to picket counts for cuts and waste on angled runs
- Corner posts and end posts need extra bracing
- Sloped terrain may require stepped or racked panels
- Double-gate openings (for vehicles) need heavier posts and wider hardware
This calculator gives you a solid starting estimate. For complex layouts with many corners or slopes, consider sketching your fence line and counting sections manually to fine-tune the numbers. If you plan to seal or stain the finished boards, follow up with our fence stain calculator to estimate gallons and cost.
Frequently Asked Questions
How many fence posts do I need?
Divide your total fence length in feet by the post spacing (typically 6 or 8 feet), then add 1. For example, a 100-foot fence with 8-foot spacing needs 14 posts (100 / 8 + 1 = 13.5, rounded up to 14). Add extra posts for each gate and corner.
How much does it cost to build a fence?
A wood privacy fence costs $15-$35 per linear foot for materials. A 150-foot privacy fence typically costs $2,250-$5,250 in materials alone. Picket fences run $10-$20 per foot, and split rail fences cost $8-$15 per foot. Labor adds $15-$30 per linear foot if hiring a contractor.
What is the best fence post spacing?
8 feet is standard for most wood fences and matches pre-cut rail lengths. Use 6-foot spacing for taller privacy fences (over 6 feet) or in areas with high winds for extra strength. Never exceed 8 feet between posts — the rails will sag over time.
How many pickets do I need for a privacy fence?
For standard 5.5-inch-wide pickets with no gaps, you need about 21-22 pickets per 8-foot section. Multiply the number of sections by 22, then add 10% for waste. A 100-foot fence with 8-foot spacing has about 12-13 sections, needing roughly 290-315 pickets total.
Do I need a permit to build a fence?
Most cities require a permit for fences over 6 feet tall. Even shorter fences may need a permit depending on your location, HOA rules, and proximity to property lines. Always check with your local building department before starting. You'll also want to call 811 to mark underground utilities before digging post holes.