How to Calculate Deck Board Linear Feet
Decking is often planned and priced by linear feet. To estimate the amount of field decking, first determine how many board rows cover the deck width, then multiply the row count by the length each row runs.
1. Identify the board run
Measure the deck dimension parallel to the boards. This is the board run length. If each row needs one full board across that dimension, the row length is the same as the deck length.
2. Calculate the number of board rows
Convert the deck width to inches and use the actual board face width plus the planned gap:
Rows = ceiling((deck width in inches + gap) ÷ (board width + gap))
Use the actual physical board width rather than the nominal lumber name. A partial final row still requires material, so a whole-row calculation should not simply round down.
3. Calculate base linear feet
Once the row count is known:
Base linear feet = rows × board run length
Worked example
Suppose a rectangular deck is 12 ft wide and 16 ft long. The decking has an actual face width of 5.5 inches and a 1/8-inch gap.
First calculate the board pitch:
5.5 + 0.125 = 5.625 inches
Then calculate rows:
ceiling((12 × 12 + 0.125) ÷ 5.625) = 26 rows
Now calculate base linear feet:
26 × 16 = 416 linear feet
This is the estimated field decking before an allowance for cuts, defects, layout changes, or other project-specific material needs.
Linear feet is different from board count
Linear feet describes the total length of decking material. The number of physical boards you purchase depends on the stock length available and how efficiently the cut pieces can be used. For example, 416 linear feet does not automatically mean 26 boards; the stock board length determines the purchase count.
Allow for cuts and layout details
Add an allowance when the project has end cuts, defects, picture framing, diagonal decking, staggered joints, stairs, or other details that create extra material. The appropriate allowance depends on the layout and material.
Common mistakes
- Using nominal board width instead of actual face width.
- Forgetting to include the board gap when counting rows.
- Rounding a partial final row down.
- Treating linear feet as the same thing as physical board count.
- Forgetting separate material for picture framing, stairs, fascia, or other areas.
Use the Deck Board Calculator
For a quick estimate, use the YardCompute Deck Board Calculator. For adjusting the gap across a deck width, use the Deck Board Spacing Calculator. For the underlying board-count method, see How to Calculate Deck Boards.
FAQ
What does linear feet mean for decking?
It is the total length of decking material measured end to end, regardless of board width.
How do I convert linear feet into boards?
Divide the required linear footage by the length of the stock boards and round up as a simple planning estimate. Actual purchasing can differ when cuts and offcut reuse are considered.
Should I include waste?
Usually allow additional material for cuts, defects, layout changes, and replacement pieces. The right allowance depends on the project.
Does this include stairs or picture framing?
No. Treat stairs, borders, picture framing, fascia, and other separate areas as additional material takeoffs.
Can I use this for diagonal decking?
The same basic linear-foot concept applies, but diagonal layouts usually create more cuts and offcuts, so a project-specific allowance is appropriate.
Related calculators
Deck Board Calculator · Deck Board Spacing Calculator · Deck Board Calculation
Planning estimate: Estimates are for planning purposes only. Actual material requirements may vary based on site conditions, material specifications, installation methods, waste, and local requirements. Always verify quantities with your supplier or qualified professional before purchasing materials.