How to Use This Fence Calculator
Planning a fence project requires accurate material estimates to avoid multiple trips to the lumber yard and budget overruns. This calculator handles the math for posts, rails, pickets, and concrete.
- Select your fence type. Privacy fences are 6 feet tall with no gaps between pickets. Picket fences are 4 feet with spaced pickets. Chain link uses different materials. Choose Custom to specify your own dimensions.
- Enter the total linear feet. Measure the full perimeter where you want fencing. Include all sides even if they're not continuous.
- Specify gates and corners. Gates subtract from the fence length (you don't put pickets where gates go). Corners need extra posts for structural support.
- Add prices for a cost estimate. Check your local home improvement store for current prices on posts, rails, pickets, concrete, and gates.
- Copy or print your material list. Take it to the store or use it to get quotes from contractors.
Always buy 5-10% extra materials to account for waste, mistakes, and future repairs.
How It Works
Post Spacing and Placement
Posts are the backbone of any fence. Standard spacing is 8 feet for wood fences, which matches typical lumber lengths (8-foot rails span exactly between posts). Shorter spacing (6 feet) adds strength but increases cost. Longer spacing risks sagging rails.
The calculator places a post at each end, then spaces posts evenly between them. Corner posts are added separately because corners need structural reinforcement. The fence changes direction and creates stress points.
Burial Depth
A properly set fence post has 1/3 of its length underground. For a 6-foot tall fence, you need 8-foot posts: 2 feet buried, 6 feet exposed. This depth provides the leverage needed to resist wind and leaning forces.
In cold climates, posts should extend below the frost line (typically 36-48 inches) to prevent heaving when the ground freezes and thaws. Check your local building codes for requirements.
Rail Configuration by Fence Type
Privacy fences use three horizontal rails (top, middle, bottom) because the heavy, continuous pickets need extra support. Picket fences typically use two rails since the shorter, spaced pickets are lighter. Chain link fences use a top rail with tension wire; the chain link fabric provides its own structure.
Examples
Example 1: 100ft Privacy Fence
A standard backyard privacy fence:
- Type: Privacy (6ft)
- Length: 100 linear feet
- 1 gate (4ft), 4 corners
- 8ft post spacing
Materials: 17 posts (8ft long), 48 rails, ~209 pickets, 34 bags of concrete, 1 gate kit. At typical prices ($15/post, $8/rail, $2/picket, $5/concrete, $150/gate), total is approximately $1,100-1,300.
Example 2: 60ft Picket Fence with Gate
A classic front yard picket fence:
- Type: Picket (4ft)
- Length: 60 linear feet
- 1 gate (3ft), 2 corners (end posts at house)
- 8ft post spacing
Materials: 10 posts (6ft long), 18 rails, ~114 pickets, 20 bags of concrete, 1 gate kit. Picket fences cost less due to shorter posts and fewer rails, approximately $500-700.
Example 3: 150ft Chain Link Fence
An economical property perimeter:
- Type: Chain Link (4ft)
- Length: 150 linear feet
- 1 gate (4ft), 4 corners
- 10ft post spacing (chain link allows wider spacing)
Materials: 20 posts, 19 top rails, 40 bags of concrete, plus chain link fabric, tension bars, and fittings. Chain link is the most economical option at approximately $800-1,200 for materials.
Frequently Asked Questions
How deep should fence posts be?
The general rule is to bury 1/3 of the total post length underground. For a 6-foot fence, use 8-foot posts with 2 feet buried. In areas with frost, posts should extend below the frost line (typically 36-48 inches in cold climates) to prevent heaving.
How far apart should fence posts be?
Standard spacing is 6-8 feet between posts. Privacy and picket fences typically use 8-foot spacing to match standard lumber lengths. Chain link fences can space posts up to 10 feet apart. Closer spacing (6 feet) provides extra strength in high-wind areas.
How many bags of concrete per fence post?
For standard 4x4 posts in average soil, use 1-2 bags of 50-60lb concrete per post. Larger 6x6 posts or loose/sandy soil may need 3-4 bags. Corner and gate posts need extra concrete for added strength. Always set posts in holes 3x the post width.
Do I need a permit for a fence?
Most areas require permits for fences over 6 feet tall, and many require them for any fence. Check with your local building department. You'll also need to verify property lines (get a survey if unsure), check HOA rules, and call 811 to mark underground utilities before digging.
What's the cheapest type of fence?
Chain link is typically the cheapest option ($5-15 per linear foot installed). Pressure-treated pine picket fencing is the most affordable wood option ($10-20/ft). Privacy fencing costs more ($15-35/ft). Cedar and composite fences are premium options ($25-50+/ft).
How long does a wood fence last?
Untreated pine lasts 5-10 years. Pressure-treated pine lasts 15-20 years with maintenance. Cedar naturally resists rot and lasts 15-20 years. Redwood can last 20-25 years. Proper maintenance (staining/sealing every 2-3 years) extends lifespan significantly.