Question 1

How do I convert square feet to linear feet?

Accepted Answer

To convert square feet to linear feet, use this formula: Linear Feet = (Square Feet × 12) ÷ Board Face Width (in inches). For example, 400 SF of 5/4x6 decking (5.5" face): 400 × 12 ÷ 5.5 = 873 linear feet. If you're using boards with a gap between them (like decking), add the gap to the face width: 400 × 12 ÷ (5.5 + 0.125) = 853 LF. Always add 10% for waste.

Question 2

What is the difference between square feet and linear feet?

Accepted Answer

Square feet (SF) measures area — the total surface you need to cover (length × width). Linear feet (LF) measures length — how many feet of boards you need to buy. Since boards have a specific width, you need more linear feet of narrow boards (like 1x4) than wide boards (like 1x6) to cover the same area.

Question 3

How do I calculate square footage for a deck?

Accepted Answer

Multiply the length by the width of your deck in feet. For example, a 20 ft × 16 ft deck = 320 square feet. For irregular shapes, break the area into rectangles, calculate each one, and add them together. For L-shaped decks, split into two rectangles.

Question 4

Why does gap spacing matter in decking calculations?

Accepted Answer

Decking boards are installed with a small gap (typically 1/8" to 1/4") between them for drainage and expansion. This gap slightly increases the total linear feet needed because each board covers its face width PLUS the gap width in the overall run. For 400 SF with 5.5" boards: without gap = 873 LF, with 1/8" gap = 853 LF. The difference grows with larger projects.

Question 5

What is face width vs nominal width?

Accepted Answer

Nominal width is the name of the board (e.g., "1x6"). Face width is the actual visible surface after milling. A 1x6 board has a 5.5" face width. For profiled boards like Tongue & Groove or Shiplap, the face width is even smaller (typically 5") because the tongue/overlap is hidden. Always use face width for material calculations.

Question 6

How much waste should I plan for?

Accepted Answer

We recommend 10% waste for most projects. Professional installers with simple rectangular layouts may use 7%. DIY projects or complex layouts with angles, curves, or patterns should plan for 13–15%. Waste accounts for cuts at ends, defects, mistakes, and board-end culling. Running short mid-project is far more costly than ordering a small surplus.

Question 7

How do I calculate siding material for Tongue & Groove or Shiplap?

Accepted Answer

For T&G, Shiplap, and Rainscreen profiles, use the exposed face width — not the nominal board width. A T&G 1x6 has a 5" exposed face (the tongue is hidden). Measure your total wall area (height × length), subtract window and door openings, then divide by the face width: Wall SF × 12 ÷ face width = Linear Feet. Add 10–15% waste.

Question 8

How do I calculate material for a fence?

Accepted Answer

For fencing: 1) Measure total fence line length (linear feet of run). 2) Divide by (picket width + gap) to get the number of pickets. 3) Multiply pickets × fence height = total picket linear feet. 4) Posts: divide fence run by post spacing + 1. 5) Rails: 3 per section × post spacing length. Add 10% waste to picket material.

Question 9

What is the formula for Rainscreen coverage?

Accepted Answer

Rainscreen profiles typically have a 4.75" face width for 5/4x6 boards or 2.875" for 5/4x4 boards. Calculate the same way as other siding: Wall SF × 12 ÷ face width = LF needed. Rainscreen is installed with a gap behind it on furring strips, but the face-to-face calculation is the same as other cladding profiles.

Question 10

Can I use these calculators for composite or softwood decking?

Accepted Answer

Yes! The math is the same for any material. Just enter the correct face width for your specific product. Our calculators work for Ipe, Cumaru, Tigerwood, Garapa, cedar, redwood, pressure-treated, or composite decking. The key variable is always the face width of the board.

Question 11

How many hidden fastener clips do I need per square foot?

Accepted Answer

For 5.5" boards at 16" joist spacing: approximately 175 clips per 100 SF. For 3.5" boards at 16" spacing: approximately 275 clips per 100 SF. Tighter joist spacing (12" OC) requires more clips. Our decking calculator includes fastener estimates based on your specific board size and joist spacing.

Question 12

What's the difference between linear feet and board feet?

Accepted Answer

Linear feet (LF) measures the length of a board regardless of width or thickness — it's what you order for decking, siding, and fencing. Board feet (BF) is a volume measurement: (thickness × width × length) ÷ 144. Board feet is more common for rough lumber purchasing. For decking and siding, linear feet is the standard unit.

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