How to calculate deck board count and linear feet before buying more
Deck board estimates depend on more than square footage. Board face width, the gap between rows, the direction boards run and the stock lengths available all affect how many boards you need.
Open the free deck board calculator →Convert deck dimensions into rows, linear feet and whole boards
Start with the deck dimensions and the actual face width of the decking. Add the intended gap between rows, because spacing changes the number of rows required. Multiply the row count by the distance each row must span to estimate linear feet, then convert that total into whole boards based on the lengths you can buy or already own.
Repairs and small areas need an additional check: a leftover board can contain enough total length but still be unusable if it cannot span the required framing or place an end joint over proper support.
Compare the deck requirement with your saved boards and offcuts
Leftover lets you start with the material already in your garage or shed. Use the calculator to estimate the purchase gap instead of automatically buying a full new batch. For repair-specific planning, see the decking repair guide and small decking area guide.
Deck board calculator FAQ
Does board spacing change the count?
Yes. The installed gap is part of the repeating row width, so a wider or narrower gap can change the number of deck-board rows across the deck.
Why calculate linear feet?
Linear feet converts the row layout into the total length of decking needed, which can then be compared with the lengths of full boards and offcuts.
Can leftover deck boards be used for repairs?
They can when the profile, thickness, material and condition are compatible and the replacement piece can be supported correctly by the framing.