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Fence Calculator

Posts, rails, pickets or panels, concrete and gates for wood, chain-link, vinyl or split-rail fences.

How this is calculated

Sections = (fence length − gate widths) ÷ post spacing. Posts = sections + 1 (open run) or sections (closed loop) + 1 per gate. Boards: privacy 5.5 in wide, picket 5 in pitch. Post length = height + 2 ft below ground.

Choose your fence style, total length, height and post spacing. Add gates and the calculator works out sections, posts, rails, boards or panels, concrete bags, fasteners and a total material cost.

Results are estimates for planning purposes only. Real-world quantities depend on site conditions, materials and workmanship. Always verify measurements, follow local building codes and confirm quantities with your supplier or a qualified professional before ordering or building.

About the Fence Calculator

A fence project lives or dies on the materials list: too few pickets and the crew stands idle, too many and you store lumber for years. This calculator turns linear footage into a complete shopping list — posts, pickets or panels, horizontal rails and concrete bags — for wood privacy, picket, vinyl and chain-link fences, including gates.

How to use

  1. Enter the length of each fence run in feet, measured along the ground where the fence will stand.
  2. Choose your style: privacy (tight pickets), picket (spaced boards), pre-built panels or chain-link.
  3. Set post spacing — 8 feet is standard for wood, 6 feet for high-wind areas or tall fences.
  4. Enter picket width and the gap between pickets (zero for a privacy fence).
  5. Add gates: each needs two sturdier gate posts, and its opening comes out of the picket count.

Understanding your results

The post count includes line posts plus one extra per run, with gate posts listed separately since they should be larger and set deeper. The picket or panel count is your lumber order including cutting waste. Rails run two per section for 4-foot fences, three for 6-foot. Concrete is in bags per post hole.

How the calculation works

Posts are run length divided by spacing, plus one per run, rounded up. Pickets are run length in inches divided by picket width plus gap — a 100-foot run with 5.5-inch pickets and a half-inch gap needs 200 pickets. Rails are two or three per 8-foot section by height. Concrete runs about one 50 lb bag per standard post hole, doubled for gates and corners.

Fence Calculator FAQs

Eight feet on center is the standard for wood privacy and picket fences — it matches common rail lengths and keeps lumber costs down. Drop to 6 feet in high-wind areas or for fences over 6 feet tall. Chain-link posts typically go 10 feet apart. Wider spacing saves posts but lets rails sag, so never stretch past 8 feet on a wood fence.
Set posts at least 2 feet deep, or one-third of the post height — whichever is deeper. A 6-foot fence needs posts 2.5 to 3 feet in the ground. In cold climates, the bottom of the hole must sit below the frost line or freeze-thaw cycles will heave the posts. Gate posts should go 6 inches deeper than line posts and get extra concrete.
Roughly one 50 lb bag per standard post hole for a 4×4 wood post in a 10-inch diameter hole about 30 inches deep. Corner posts and gate posts, which take more stress, deserve two bags each. Fast-setting concrete mix is popular for fences because each hole sets in 20 to 40 minutes without mixing — just pour in the dry mix and add water.
Subtract the gate opening from the picket count and add two gate posts, which should be 4×6 or 6×6 rather than 4×4, set deeper with more concrete. A walk gate is typically 3 to 4 feet wide; a double drive gate runs 10 to 12 feet. Hang gates so they swing inward and leave an inch of clearance underneath for ground movement.
Wood costs roughly half as much upfront but needs staining every 2 to 3 years and lasts 10 to 15 years. Vinyl costs more initially, needs almost no maintenance and lasts 20 to 30 years. Over 20 years the total cost is often similar — vinyl wins on time saved, wood wins if you like the natural look and lower initial outlay.
Nabil Sharif, founder of CalcDune

Written by

Nabil Sharif

Founder of CalcDune — a free library of 137 online calculators for finance, health and everyday math. Every calculator shows the formula behind its result, so you can see exactly how your numbers are worked out.

More articles by Nabil →

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