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Fence Rail Calculator

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

Size
Waste and price (optional)
$

Material needed

9 railsBuy this many

Estimated cost

Material cost$90
Fence Rail

How to calculate fence rail

Fence rails, about 3 rails per 8 foot section, with waste.

Formula: quantity = length × 0.375 × (1 + waste %) = 20 × 0.375 × 1.10 = 9 rails.

Worked example

Example: 20 ft long. Quantity: 9 rails, about $90 at $10 per rails.

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 rail do I need?

Example: 20 ft long. Quantity: 9 rails, about $90 at $10 per rails.

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.