⚡ US, UK & Australian Standards (Imperial & Metric)

Post, Rail & Picket Fence Estimator

Calculate 4×4 wood posts, fast-setting concrete bags per hole, 2×4 horizontal backer rails, dog-ear pickets, and exterior fasteners.

Post, Rail & Picket Fence Estimator

Universal calculator for 4×4 posts, concrete bags, 2×4 rails, and individual pickets.

Quick:
4×4 Fence Posts
15posts

8ft or 10ft long (bury 3ft) • 1 gate post

Includes 1 heavy-duty gate latch & hinge hardware kit
Concrete Bags
45bags

Or 30 bags of 80 lb standard mix

Accessory: ~5 bags of #57 gravel (pour 4" at base of holes for drainage)
2×4 Backer Rails
41rails

3 rails per section (8ft lumber)

Vertical Pickets
236pickets

+ 10 lbs screws (1,416 fasteners)

Disclaimer: Calculations provided are estimates for preliminary material planning only. Actual yields vary based on subgrade compaction, site grading, waste, and local trade practices. QuickRenoTools assumes no liability for material shortages, structural failures, code non-compliance, vehicle overloads, or jobsite injuries. Verify all structural spans, retaining wall heights, and concrete mix designs with a licensed engineer, certified contractor, or local building authority prior to purchase and construction. Legal Disclaimer

Pre-Calculated Quick Reference

Privacy Fence Materials Cheat Sheet (6-Foot Tall, 8ft Spacing)

Quick reference table showing 4x4 posts, fast-setting concrete bags, 3 horizontal 2×4 rails, and 5.5" (140mm) dog-ear pickets with 10% waste.

Swipe table horizontally to see all columns →
Fence RunPosts (8ft / 2.4m Spacing)Concrete Bags (3/post)Horizontal Rails (3 Rails)5.5" Pickets (140mm)
50 ft (15m) Run8 posts (4×4 / 90×90)24 bags (50lb / 20kg)21 rails (3 rails/bay)118 pickets (116 palings)
100 ft (30m) Run14 posts (4×4 / 90×90)42 bags (50lb / 20kg)39 rails (3 rails/bay)235 pickets (231 palings)
150 ft (45m) Run20 posts (4×4 / 90×90)60 bags (50lb / 20kg)57 rails (3 rails/bay)352 pickets (347 palings)
200 ft (60m) Run26 posts (4×4 / 90×90)78 bags (50lb / 20kg)75 rails (3 rails/bay)470 pickets (462 palings)
300 ft (90m) Run39 posts (4×4 / 90×90)117 bags (50lb / 20kg)114 rails (3 rails/bay)704 pickets (693 palings)
Values based on standard 6-foot (1.8m) privacy fence with 8-foot (2.4m) post spacing, 3 horizontal rails, and 10% picket cutting waste (0 gates).
1 US picket = 5.5" dog-ear (0.46875 ft pitch) | 1 Metric paling = 140mm board + 3mm gap (143mm pitch)
⚖️ Construction Liability & Code Notice

Disclaimer: Calculations provided are estimates for preliminary material planning only. Actual yields vary based on subgrade compaction, site grading, waste, and local trade practices. QuickRenoTools assumes no liability for material shortages, structural failures, code non-compliance, vehicle overloads, or jobsite injuries. Verify all structural spans, retaining wall heights, and concrete mix designs with a licensed engineer, certified contractor, or local building authority prior to purchase and construction.

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— GOOD TO KNOW —

Frequently Asked Questions: Post, Rail & Picket Fence Estimator

Common questions about bag calculations, ordering bulk vs bags, and trade standards.

How far apart should wooden fence posts be spaced?

Standard residential fence posts are spaced 8 feet on-center (or 2.4 meters). In high-wind hurricane or gale regions, space posts 6 feet on-center to reduce wind sail loading on the rails.

How many bags of concrete do I need per fence post hole?

For a standard 6-foot privacy fence with a 10-inch diameter hole dug 36 inches deep, plan on 2.5 to 3 bags of 80 lb concrete (or 3 to 4 bags of 50 lb Fast-Setting concrete) per post hole.

How deep should fence posts be buried in the ground?

The general rule of thumb is to bury 1/3 to 1/2 of the total above-ground post height. For a 6-foot fence, dig holes at least 30 to 36 inches deep. In freezing climates, dig 6 inches below your local winter frost line.

How many horizontal 2x4 backer rails are needed per fence section?

A 4-foot tall fence requires 2 horizontal 2×4 rails (top and bottom). A 6-foot or 8-foot privacy fence requires 3 horizontal rails (top, middle, and bottom) to prevent thin vertical pickets from warping and bowing in the sun.

How many pickets do I need per linear foot of fence?

Standard 5.5-inch dog-ear pickets (with a 1/8" gap for wood expansion) require 2.1 to 2.2 pickets per linear foot. A 100-foot fence requires ~220 pickets (order 235 to 240 for 10% waste).

Should fence pickets touch the ground or lawn?

No. Leave a 2-inch gap between the bottom of the pickets and the ground (or install a sacrificial pressure-treated rot board). Direct ground contact causes pickets to wick ground moisture, leading to premature rot and weed trimmer damage.

Should I use nails or screws to attach fence pickets?

Use 1-5/8" or 2" hot-dipped galvanized or ceramic-coated exterior screws. Screws have significantly higher withdrawal strength and prevent pickets from popping loose when the lumber swells and contracts.

How long does a pressure-treated wooden privacy fence last?

A properly installed pressure-treated pine fence lasts 15 to 20 years. Cedar fences last 20 to 25 years. Applying an oil-based penetrating UV-sealer every 2 to 3 years doubles picket lifespan.

Do I need my neighbor’s permission or a survey before building a fence?

You do not need neighbor permission if building entirely within your property boundary line (commonly set back 2 to 6 inches inside the line). However, getting a certified boundary survey is strongly advised to prevent boundary disputes.

Should fence post holes have gravel at the bottom?

Yes. Always pour 4 to 6 inches of coarse crushed stone (#57 gravel) into the bottom of the hole before dropping in the post. This allows water entering the wood post end-grain to drain into the subsoil, preventing bottom rot.

⚖️

Construction Liability & Engineering Disclaimer

Essential legal notices, engineering thresholds, and safety limits

Disclaimer: Calculations provided are estimates for preliminary material planning only. Actual yields vary based on subgrade compaction, site grading, waste, and local trade practices. QuickRenoTools assumes no liability for material shortages, structural failures, code non-compliance, vehicle overloads, or jobsite injuries. Verify all structural spans, retaining wall heights, and concrete mix designs with a licensed engineer, certified contractor, or local building authority prior to purchase and construction.

1. Engineering Certification Thresholds

Building materials carry severe physical and financial liability. Certain project dimensions exceed standard residential rules of thumb and legally mandate certified structural engineering:

  • Retaining Walls: Walls exceeding 3 to 4 ft (0.9 to 1.2 m) require stamped structural engineering calculations, soil geogrid reinforcement analysis, and municipal building permits (IBC 1807.2 / AS 4678). Surcharge loads (slopes, driveways, or structures above the wall) trigger engineering at any height.
  • Concrete Slabs & Footings: Calculations apply strictly to residential grade-supported slabs and gravity footings. Suspended structural designs, elevated decks, and commercial foundation footings require certified engineering drawings.
  • Timber & Carpentry: Structural ledger connections, multi-story post sizing, and beam spans must be verified against local building codes (IRC 2021 / AS 1684 / Eurocode 5).

2. Vehicle Payload & Hauling Safety

Hauling bulk aggregates, gravel, or heavy concrete bags carries severe risks of axle failure, snapped leaf springs, and tire blowouts:

General physics estimate only. Payload ratings vary by vehicle trim, cab configuration, bed length, and suspension packages. Always check your specific driver-door tire and loading placard (Gross Vehicle Weight Rating [GVWR] minus vehicle curb weight) before hauling aggregate or bagged concrete.

3. Subgrade Compaction & Material Variances

Quarry aggregates vary by ±15% based on moisture content (damp vs. bone-dry stone). Crushed road base consolidates by 15% to 20% under mechanical plate compactors. Excavation depth irregularities and formwork deflection can increase concrete requirements by 10% or more. Always order an appropriate waste contingency.

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