How this calculator works
A linear foot is a length, and a square foot is an area, so to convert you need a width. Multiply the linear feet by the width in feet (inches divided by 12) to get square feet. To go the other way, divide the square feet by the width in feet.
Worked example: 100 linear feet of 5½ inch board covers 45.83 square feet. Going back, 100 square feet of that board is 218.2 linear feet, which is 19 boards of 12 ft.
Square feet in 100 linear feet, by width
Multiply the width in inches by 100 and divide by 12.
| Width | Square feet per 100 linear ft | Linear feet per 100 ft² |
|---|---|---|
| 1.5 in | 12.5 | 800.0 |
| 2.5 in | 20.8 | 480.0 |
| 3.5 in | 29.2 | 342.9 |
| 5.5 in | 45.8 | 218.2 |
| 7.25 in | 60.4 | 165.5 |
| 9.25 in | 77.1 | 129.7 |
| 11.25 in | 93.8 | 106.7 |
| 12 in | 100.0 | 100.0 |
Tips before you buy
- Use the actual width of the board, not the nominal size. A "1×6" is 5½ inches wide, and a "2×4" is 3½ inches.
- Flooring and siding often cover less than the board width because of the overlap (the "reveal"): use the covered width.
- For a rough check, a 12 inch wide board gives one square foot for every linear foot.
- Add 5 to 15% for waste, and round up to whole boards.
- Fence boards laid side by side with no gaps are a good use of this conversion: linear feet of boards in a fence section.
Tools & materials for this project
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Frequently asked questions
How do you convert linear feet to square feet?
Multiply by the width in feet. 100 linear feet of a 5½ inch board is 100 × 5.5 ÷ 12 = 45.83 square feet.
How many square feet in 100 linear feet?
It depends on the width: 100 linear feet is 100 square feet only for a board 12 inches wide. For a 6 inch board it is 50, and for a 3½ inch trim 29.2 square feet.
How many linear feet in a square foot?
For a 5½ inch board, 2.18 linear feet. For a 12 inch board, exactly 1.
How do I convert square feet to linear feet for flooring?
Divide the square feet by the width of the plank in feet. Allow 5 to 15% for waste, and round up to whole boxes or boards.
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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.