BuildCalcFree calculators

Fence Post Calculator

Enter your size to get fence post quantity, plus an estimated cost. Waste is included and prices are editable.

Size
Waste and price (optional)
$

Material needed

3 postsBuy this many

Estimated cost

Material cost$45
Fence Post

How to calculate fence post

Fence posts, one post about every 8 feet, with waste.

Formula: quantity = length × 0.125 × (1 + waste %) = 20 × 0.125 × 1.10 = 3 posts.

Worked example

Example: 20 ft long. Quantity: 3 posts, about $45 at $15 per posts.

Tips

Measure the full area, then subtract large openings if you want an exact count. Order a little extra for cuts and breakage, and confirm quantities with your supplier before you buy.

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Frequently asked questions

How much fence post do I need?

Example: 20 ft long. Quantity: 3 posts, about $45 at $15 per posts.

How much waste should I add?

Add 10% for straight areas and 15% for areas with many cuts, corners and openings.

Are the prices accurate?

Prices are editable estimates. The defaults are typical US figures, and your local price can be higher or lower.

Last updated 2026-10-27. Formulas checked by Bilal Mughal.