Decking Board Calculator

Boards, optional fasteners, and rough cost.

Decking Board Calculator

Estimate how many decking boards to buy from deck size, board size, gap, and board direction. Optional joist spacing and screw-pack inputs add a simple fastener estimate without changing the core board count workflow.

Decking Inputs

Measurement systemSystem

Board directionDirection

Deck length / width unit

Board length unit

Board width / gap / joist spacing unit

Deck lengthDeck length

Deck widthDeck width

Board widthBoard width

Sold board lengthBoard length

Gap between boardsGap

Waste allowance (%)Waste %

Optional joist, screw, and price fields

Joist spacing

Screws per board per joist

Price per board

Screws per pack

Price per screw pack

Fastener math stays optional so the calculator still gives a board answer even when only deck and board dimensions are known.

This static batch focuses on the core board-count workflow. Picture-frame borders, breaker boards, hidden-clip layouts, and multi-section deck plans remain later-phase enhancements.

Decking calculator FAQ

Why does board direction matter?
Changing direction swaps which deck dimension is split into board runs and which is covered by board widths plus gaps.

Do I need joist spacing to use this?
No. Joist spacing is only used for the optional fastener estimate, not the main board count.

Planning fence materials too? Need a screw count only? Back to calculator home