Board Feet to Square Feet Converter
Convert board feet to square feet (or reverse) by entering the thickness. Works for any lumber thickness.
Formula
Square Feet = Board Feet ÷ Thickness (in inches)
Why thickness matters: board feet measure volume. The same volume of thicker lumber covers less surface area.
Board Feet → Square Feet Conversion Table
Values by board feet amount and lumber thickness (nominal).
| Board Feet | 3/4" (3/4) | 4/4 (1") | 5/4 (1.25") | 6/4 (1.5") | 8/4 (2") | 10/4 (2.5") | 12/4 (3") |
|---|---|---|---|---|---|---|---|
| 10 BF | 13.33 SF | 10 SF | 8 SF | 6.67 SF | 5 SF | 4 SF | 3.33 SF |
| 25 BF | 33.33 SF | 25 SF | 20 SF | 16.67 SF | 12.50 SF | 10 SF | 8.33 SF |
| 50 BF | 66.67 SF | 50 SF | 40 SF | 33.33 SF | 25 SF | 20 SF | 16.67 SF |
| 100 BF | 133.33 SF | 100 SF | 80 SF | 66.67 SF | 50 SF | 40 SF | 33.33 SF |
| 200 BF | 266.67 SF | 200 SF | 160 SF | 133.33 SF | 100 SF | 80 SF | 66.67 SF |
| 500 BF | 666.67 SF | 500 SF | 400 SF | 333.33 SF | 250 SF | 200 SF | 166.67 SF |
| 1000 BF | 1333.33 SF | 1000 SF | 800 SF | 666.67 SF | 500 SF | 400 SF | 333.33 SF |
How to Convert Board Feet to Square Feet
Board feet measure volume. Square feet measure area. To bridge the two you need thickness:
Square Feet = Board Feet ÷ Thickness (in inches)So 100 board feet of 4/4 lumber (1" thick) covers exactly 100 square feet. The same 100 board feet in 8/4 (2" thick) only covers 50 square feet — double the thickness means half the coverage area.
For the reverse — converting square feet to board feet — multiply instead:
Board Feet = Square Feet × Thickness (in inches)Why This Conversion Matters
Hardwood lumber is sold by the board foot. Many projects specify coverage in square feet. The conversion comes up constantly in:
- Hardwood flooring — you order by the board foot, but your floor plan is in square feet. At 4/4 (1"), they're equal. At 3/4", you'll get more coverage per board foot than you might expect.
- Wood paneling and wainscoting — wall coverage is measured in SF; lumber is priced in BF.
- Deck boards — 5/4 cedar decking is common. 100 BF of 5/4 stock covers only 80 SF, not 100 SF.
- Veneer and shop lumber — thin stock covers far more area per board foot than thick stock.
Worked Examples
Example 1 — Hardwood floors: You're installing 4/4 (1") white oak floors. You bought 300 board feet. How many square feet will it cover?
300 BF ÷ 1" = 300 SF
Example 2 — Cedar decking: Your deck needs 480 SF of coverage in 5/4 (1.25") cedar. How many board feet?
480 SF × 1.25" = 600 BF
Example 3 — Walnut wall panels: You have 150 BF of 6/4 (1.5") walnut for paneling. How much wall area will it cover?
150 BF ÷ 1.5" = 100 SF
At 1 Inch Thick, Board Feet Equal Square Feet
When lumber is exactly 1 inch thick, board feet and square feet are numerically the same. This is because a board foot is defined as 1" × 12" × 12" — if you lay those boards flat, 1 BF covers exactly 1 SF of surface. Thicker lumber contains more volume in the same footprint, so it covers less area per board foot. Thinner lumber (like 3/4" finish stock) covers more area per board foot.
For detailed board foot calculations by size, see the board foot chart. To estimate project quantities with waste, use the Lumber Estimator.
Frequently Asked Questions
How many square feet are in 100 board feet of 4/4 lumber?
100 square feet. At exactly 1 inch thick, board feet and square feet are numerically equal. The formula is SF = BF ÷ thickness, so 100 BF ÷ 1 = 100 SF.
How do I convert board feet to square feet for hardwood flooring?
Divide your board feet by the thickness in inches. For 4/4 flooring (1 inch thick), SF = BF. For 3/4-inch flooring, SF = BF ÷ 0.75. For 5/4 (1.25 inches), SF = BF ÷ 1.25.
How many board feet do I need to cover 200 square feet with 5/4 decking?
250 board feet. Multiply square feet by the thickness in inches: 200 SF × 1.25 = 250 BF.
Does board width affect the board feet to square feet conversion?
No. The conversion depends only on thickness — width is already baked into the board foot calculation. BF already accounts for width, so only thickness is needed to convert to square feet.