Decking Calculator
Estimate decking rows, boards, linear footage, and cost.
Estimate decking boards
Material estimate
Whole stock boards
- Deck surface area
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- Board rows
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- Linear feet including waste
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- Board cost
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Board count is a linear-foot estimate, not a cut plan: it assumes offcuts can be reused elsewhere. If each row must be a full-length board, order one board per row instead — when stock is longer than the deck, that can be well over the count shown here.
Joint layout, picture framing, defects, and all framing are excluded.
Your entries and results stay in this browser. This tool does not send, save, or add them to the page address.
How to use the decking calculator
Enter deck length in the direction boards run and deck width across the rows. Add actual installed board width, intended gap, available stock-board length, waste allowance, and price per stock board.
Formula and assumptions
Row count divides deck width by installed board width plus gap, accounting for no gap outside the last board, and rounds up. Linear footage is row count multiplied by deck length and waste. Whole stock boards are linear footage divided by stock length and rounded up.
Important limitations
The whole-board result is a linear-foot purchasing estimate, not a cut plan. Staggered joints, required joist bearing, picture framing, breaker boards, grain or color selection, unusable offcuts, board defects, and stock availability can increase the order. Expansion gaps vary by material and installation temperature; follow the manufacturer.
A deck is a structure that carries people above the ground, and this tool estimates only the surface boards. Ledger attachment and its flashing are the most common cause of deck collapse; along with joist sizing, spans, footings, and guard and railing strength they are life-safety details that must be designed and inspected, not inferred from a board count.
This tool excludes framing, foundations, ledgers, flashing, stairs, railings, fascia, hardware, permits, labor, and structural design. Confirm span tables, fastening, drainage, local code, product instructions, and final quantities before purchase or construction.
Frequently asked questions
Why does the calculator ask for installed board width?
Nominal lumber names may not equal actual face width. Use the installed face width specified or measured for the product.
How are board gaps handled?
Row count uses the entered installed board width plus the planned gap, without placing an extra gap beyond the final row.
Does the result plan board joints?
No. It converts required row length into total linear feet and then stock boards. Joint placement and usable offcuts require a layout.
Are framing materials included?
No. Joists, beams, posts, footings, hardware, fascia, stairs, railings, fasteners, and finishes are outside this surface-board estimate.