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Fencing & Decking Calculators — Posts, Rails & Deck Boards

Fast, free fencing and decking calculators for posts, rails, and deck boards. Enter your run length to get material estimates and cost totals instantly.

Example values provided — edit for your project.

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Fencing & Decking

posts · rails · boards

Fence Posts & Rails

Estimate posts, rails, and concrete footing bags for a fence run, based on total length and post spacing.

Posts needed
Rails needed
Concrete bags needed
Estimated cost

Deck Boards

Estimate deck boards needed for a given deck area, board width, and gap spacing, with a waste factor for cuts.

Deck area
Boards needed
Estimated cost

Planning a Fencing or Decking Project

Fences and decks share a common building block — evenly spaced structural members (posts or joists) supporting a surface layer (rails or deck boards) — which is why they're grouped together here even though they're different projects. Both calculators use spacing-based math to convert a total run length into a material count.

How These Calculators Work Together

The Fence Post & Rail calculator estimates posts, horizontal rails, and the concrete needed for post footings, all from your total fence length and post spacing. The Deck Board calculator uses a similar spacing approach but works across the deck's width, converting board width and gap spacing into a board count.

Frequently Asked Questions

What's a typical post spacing for a fence?

8 feet on-center is a common standard for wood fence panels, though pre-made panel systems often come in fixed widths that determine spacing for you. Confirm against your specific fencing material before finalizing your post layout.

Do these calculators account for stairs or railings?

No — the Deck Board calculator estimates decking surface material only. Stairs, railings, and structural framing (joists, beams, footings) beneath the deck surface need to be planned and estimated separately.