You're eyeing a new fence around your property, but first you need to know: how many posts, boards, and how much concrete does this actually cost?
Fencing is measured in linear feet. A 200-foot perimeter fence requires specific quantities of posts (spaced apart), boards (running between posts), concrete (for footing), and hardware. Underestimating any component stalls the project; overbuying wastes money. Our fence calculator converts your perimeter and spacing into exact material quantities.
What This Calculator Does
This tool calculates fence materials based on the perimeter you're fencing, post spacing (typically 6 feet apart), and board dimensions. You input the total linear feet of fencing, desired post spacing, fence height, and board size (typical is 1ร6 or 1ร8 lumber). The calculator estimates the number of posts needed, linear feet of boards (and stringers for frame), concrete volume for post footings, and applies a 10% waste factor.
How to Use This Calculator
Step 1: Measure your property perimeter in linear feet. Walk the fence line with a tape measure or use property survey documentation. For an irregular lot, measure each side and add them together.
Step 2: Decide on post spacing. Standard residential fencing uses 6-foot spacing (so a 200-foot perimeter needs roughly 33โ34 posts). Some styles use 4-foot spacing (more posts, more sturdy) or 8-foot spacing (fewer posts, saves money but less rigid).
Step 3: Determine fence height. Standard is 4โ6 feet for privacy fences, 3โ4 feet for picket fences, and 2โ3 feet for decorative borders. Height affects board quantity and visual impact.
Step 4: Select board dimensions. Common picket fences use 1ร4 boards; privacy fences use 1ร6 or 1ร8. Wider boards cover the height faster but are pricier per linear foot.
Step 5: The calculator shows post count, total linear feet of boards and stringers (horizontal frame pieces), concrete volume for footings, and total board feet of lumber. Use this to order materials.
The Formula Behind the Math
Fence calculations have two main components:
Number of Posts = (Perimeter Linear Feet รท Post Spacing) + 1
Board Feet = Total Linear Feet of Boards ร Board Width ร Board Depth รท 12
Let's work through an example: a 200-foot perimeter with 6-foot post spacing, 4-foot-tall privacy fence using 1ร6 boards.
Our calculator handles all these conversions instantly.
Picket Fence Around Small Lot (150 Linear Feet)
A property with 150 linear feet of fencing (typical small backyard perimeter), using decorative 1ร4 pickets spaced 2โ3 inches apart, 3.5-foot height.
Privacy Fence Around Full Property (300 Linear Feet)
A 300-linear-foot privacy fence (typical around a half-acre lot), 6 feet tall, using 1ร8 boards, 6-foot post spacing.
Decorative Split-Rail Fence (200 Linear Feet)
Split-rail fencing uses 4ร4 posts and larger logs instead of boards, creating a rustic look. 200 linear feet, 3-foot height, typical 6-foot spacing.
Tips and Things to Watch Out For
Confirm property lines before installing a fence. A fence built even 6 inches over a neighbor's property line can create legal issues. Hire a surveyor ($300โ500) if you're unsure, especially if there's any chance of dispute. This is cheap insurance against an expensive legal fight.
Post spacing affects cost and stability significantly. Standard 6-foot spacing balances cost and strength. Closer spacing (4 feet) uses more posts and costs more but is sturdier for windy areas. Farther spacing (8 feet) saves money but may require thicker or deeper posts. Check local building codes-some areas mandate maximum spacing.
Post depth matters for frost heave and stability. Posts should extend 2โ3 feet below grade in most climates, more in extreme cold zones (check frost line depth with your local building department). Shallow posts sink or heave in freeze-thaw cycles. Budget for deep footings in cold climates.
Always order 10โ15% more material than your calculation to account for waste, cuts, breakage, and measurement errors. Boards are cut to length, mistakes happen, and some lumber arrives damaged. A fence that winds around trees or has uneven terrain requires custom cuts. Order 10โ15% extra to avoid mid-project shortage.
Use pressure-treated lumber for all posts and underground components. Untreated wood rots within 3โ5 years when in contact with soil. Pressure-treated posts last 15โ20 years minimum. Boards can be untreated (stain-grade softwood or hardwood) if you maintain them with stain or sealant, but posts must be treated.
Pre-assembled fence panels can save time but increase material cost. Pre-made fence panels (picket or privacy) come in standard 6-foot widths and are ready to hang between posts. This eliminates measuring and cutting but costs 20โ30% more. For DIYers, building from boards is cheaper; for busy homeowners, panels are worth it.
Frequently Asked Questions
How many fence posts do I need for 100 linear feet?
With standard 6-foot spacing, you need (100 รท 6) + 1 = roughly 17โ18 posts. If spacing is 4 feet, you'd need (100 รท 4) + 1 = 26 posts. The +1 accounts for the corner post to close the loop (or starting post if the fence is not a complete loop).
What's the difference between 6-foot and 8-foot post spacing?
6-foot spacing (standard) requires more posts and is sturdier, especially in wind. 8-foot spacing uses fewer posts and costs less but requires thicker posts or stringers to prevent sagging. For a privacy fence, 6-foot is safer; for decorative fencing, 8-foot often works fine.
Do I need a permit for a residential fence?
Most jurisdictions require a permit for fences over a certain height (often 4โ6 feet) or in front-yard setbacks. Permits ensure the fence meets height regulations, setback requirements, and property line rules. Cost varies ($50โ200). Always check before building.
Can I use composite or vinyl fence materials?
Yes. Composite and vinyl fencing lasts 20+ years, requires minimal maintenance, and doesn't rot. They cost 2โ3 times more than wood but save on upkeep. Installation is similar (same post spacing and footings). Material isn't as cheap to source, so the calculator assumes wood-adjust quantities upward slightly for composite.
How deep do fence posts need to be?
Posts should extend 2โ3 feet below grade (in temperate climates). In cold regions with deep frost lines (36โ48 inches), posts must go deeper to prevent frost heave. Always check your local frost line depth and follow it. Shallow posts fail quickly.
How much concrete do I need for fence post holes?
A typical post hole is 12 inches in diameter and 30 inches deep (for a 6-foot post in temperate climate). Each hole requires roughly 0.5 cubic feet of concrete. The calculator estimates this, but confirm with your concrete supplier based on your hole size and depth.
Can I reuse an old fence for material?
Sometimes. If the wood is still sound (no rot, minimal warping), you can salvage boards and posts. However, old preservatives and nails can be hazardous, and the effort to remove and recycle often exceeds the value of the material. For new construction, buy new pressure-treated posts; recycled posts can't be trusted for underground use.
How long does a fence typically last?
Pressure-treated wood: 15โ20 years. Untreated softwood with regular maintenance (staining every 2โ3 years): 10โ15 years. Composite or vinyl: 20โ30 years. Metal: 30+ years. Lifespan depends on climate, maintenance, and material quality. Cold, wet climates age wood faster.
Related Calculators
Use the square footage calculator to measure property perimeter if you don't have survey data. The concrete calculator estimates footing material for posts. The board foot calculator helps convert lumber estimates to ordering quantities. The material cost estimator budgets the full fence project including hardware and labor.