Fence Calculator — Posts, Panels & Materials
Calculate exactly how many fence posts, rails, and pickets you need for any wood fence project. Enter your fence dimensions and spacing to get an instant material list.
Enter Dimensions
Standard dog-ear picket: 3.5 in
Privacy fence: 0 in · Standard: 0.5 in
Results
Fence Posts
14posts
Rails
26rails
Pickets
330pickets
Sections
13sections
Each section = 8 ft wide
Editorial Standards
Each calculator is reviewed for formula accuracy, unit consistency, and alignment with current U.S. building practices before publication. We verify outputs against published engineering references and real-world project data. Learn more about our methodology.
A wood privacy fence involves three separate materials — posts, rails, and pickets — each calculated differently. Getting the count wrong on any one of them means a mid-project lumber run or leftovers that never get used. The total cost difference between a careful estimate and a rough guess can easily reach hundreds of dollars on a standard residential fence.
Post spacing drives everything. The most common choice is 8 feet on center for wood privacy fences, which balances span strength with post cost. Rails per section depend on fence height: two rails for fences up to 6 feet tall, three rails for 6–8 foot fences. Picket count is calculated from your picket width plus gap — standard dog-ear pickets are 3.5 inches wide and are typically installed with a 1/4- to 1/2-inch gap for drainage and expansion.
Set your waste factor to at least 10% for pickets — end cuts and the occasional split board are inevitable. Posts and rails can be ordered at the exact count.
Specialized Versions
How the Fence Calculator Works
The calculator divides your total fence length by post spacing to get the number of sections. Posts = sections + 1 (one at each end). Rails = sections × rails per section.
Pickets are calculated by dividing total fence length by the effective picket width (picket width + gap), then applying the waste factor.
Material Estimates by Fence Length
| Fence Length | Posts (8 ft spacing) | Rails (2 per section) | Pickets (3.5 in + 0.5 gap) |
|---|---|---|---|
| 50 ft | 8 | 14 | 157 |
| 100 ft | 14 | 26 | 310 |
| 200 ft | 26 | 50 | 616 |
| 300 ft | 39 | 76 | 924 |
Values above use 8-foot post spacing, 2 rails per section, 3.5-inch pickets with 0.5-inch gaps, and 10% waste on pickets.
Pro Tips
- String a line before digging. Lay out the full fence line with stakes and string before digging a single post hole. Even small alignment errors compound into visible kinks in a finished fence — a straight string catches them before concrete is poured.
- Use pressure-treated lumber for all ground-contact posts. Above-ground lumber rated for deck boards (UC3B) is not rated for ground contact. Use UC4B or UC4C pressure-treated posts wherever the post enters the ground, or choose a composite post.
- Set gate posts deeper. Gate posts carry far more dynamic load than line posts. Set gate posts at least 4 feet deep (or frost line depth, whichever is greater) and use a larger diameter hole to maximize concrete anchoring.
- Pre-stain or paint pickets before installation. Coating all six sides of a picket is much easier before it is nailed to the rail. Pre-finishing cut ends is especially important for dimensional lumber that will be exposed to moisture.
Common Mistakes
- Ordering rails the same length as post spacing. An 8-foot section uses a rail that spans from post center to post center — the actual rail length is slightly shorter than 8 feet. Order rails at the nominal post spacing and trim on site, or confirm board lengths with your supplier before purchasing.
- Forgetting the last post. A fence with 12 sections has 13 posts, not 12. This one-off error is consistently the most common mistake in manual fence calculations and can result in a missing post at the end of the run.
- Using the same spacing for a slope. A fence running uphill requires either a stepped or raked installation. Both approaches change the effective board count and post height — a flat-ground estimate will not be accurate for a sloped run.
Fence Types and Material Options
Different fence styles use the same post-rail-picket formula but differ in dimensions, spacing, and hardware. Knowing the differences before you calculate prevents ordering the wrong materials entirely.
Wood Privacy Fence
The most common residential fence style. Posts are typically 4×4 pressure-treated at 8-foot spacing. Rails are 2×4 lumber (two per section for 6-ft fences, three for 8-ft). Pickets are dog-ear or flat-top 1×6 boards set flush for a solid privacy screen. Total material cost runs $15–$30 per linear foot installed, or $7–$15 materials-only.
Picket Fence
Decorative front-yard style. Posts are 4×4 at 6–8-foot spacing. Rails are 2×3 or 2×4. Pickets are narrow — typically 2.5 to 3.5 inches wide with a 1.5–2-inch gap between boards. The open picket pattern significantly reduces material cost: a 100-ft picket fence uses roughly half the lumber of a privacy fence for the same run.
Split-Rail Fence
Rustic style common on rural and large-lot properties. Posts are round cedar or pine set at 8–10-foot spacing. Rails (the horizontal members) slot into mortised holes in the posts — 2 rails for a 2-rail fence, 3 for a 3-rail. No pickets. Estimate posts (sections + 1) and rails (sections × rail count) only. Materials cost $4–$8 per linear foot.
Wood Species Comparison
| Species | Natural Rot Resistance | Relative Cost | Best Use |
|---|---|---|---|
| Pressure-treated pine | High (chemical treatment) | Low | Posts, rails, budget builds |
| Western red cedar | High (natural oils) | Medium | Pickets, privacy fences |
| Redwood | Very high | High | Premium decorative fences |
| Douglas fir | Low (needs sealing) | Low–medium | Painted fences, dry climates |
| Composite | Excellent (no rot) | High | Low-maintenance premium builds |
Post Size by Fence Height
Post diameter matters for structural integrity. Use 4×4 posts for fences up to 6 feet tall and 6×6 posts for fences 6–8 feet or gate posts. All posts set in soil should be rated UC4B or UC4C pressure treatment — above-ground ratings (UC3B) are not sufficient for ground contact.
2025–2026 Fence Material Pricing
Lumber prices for fencing have risen significantly due to Canadian import tariff increases that took full effect in 2025. The table below reflects current retail pricing at major home improvement stores (Home Depot, Lowe's, Menards) as of early 2026.
| Material | Unit | Retail Price | Notes |
|---|---|---|---|
| Cedar dog-ear picket (5/8×5½×6 ft) | Each | $3.78–$4.46 | Western red cedar; most common privacy picket |
| Pressure-treated picket (1×4×6 ft) | Each | $2.50–$3.50 | AC2 or MCA treatment; budget-friendly option |
| PT 2×4×8 rail (for fence sections) | Each | $5.50–$7.50 | ~17% higher YoY vs. 2024 due to Canadian tariffs |
| 4×4×8 PT post (ground contact, UC4B) | Each | $12–$16 | Must be UC4B/UC4C rated for ground contact |
| 60 lb fast-setting concrete | Bag | $6–$8 | 2 bags per post typical for 4×4 in 10-in hole |
Installed fence costs (labor + materials) typically run $15–$30 per linear foot for a wood privacy fence, depending on height, species, and regional labor rates. Cedar fences trend toward the upper end of this range.
Frequently Asked Questions
How many fence posts do I need?
Posts = sections + 1. A 100-foot fence with 8-foot sections has 12 sections and 13 posts — one post at every joint, plus one at each end.
What is the standard spacing between fence posts?
The most common post spacing is 8 feet on center for wood privacy fences. Chain-link fences often use 10-foot spacing. Vinyl fence panels typically dictate their own spacing (usually 6 or 8 feet) based on panel width.
How many pickets do I need per linear foot of fence?
Standard 3.5-inch dog-ear pickets with a 0.5-inch gap run about 2.82 pickets per linear foot.
How many rails do I need for a wood fence?
Two rails for fences up to 6 feet tall, three for 6–8 ft. Rails per section times sections gives your total.
Should I add waste when ordering fence materials?
Yes — 10% is a safe default for pickets. Rails and posts should be ordered exactly as calculated since they are pre-cut to standard lengths. Pickets may need to be trimmed at ends, so extra is wise.
How deep should fence posts be set?
The general rule is to set fence posts 1/3 of their total length underground. For a 6-foot fence, use 9-foot posts set 3 feet deep. In areas with frost, posts must extend below the frost line (often 3–4 feet in northern states).