What It Does
This calculator converts a length measured in linear feet into an area in square feet based on the width of the material. It is especially useful for flooring, decking, lumber, fencing, fabric, and trim projects where products are sold by the linear foot but you need to know how much surface area they will cover.
How to Use It
Enter the total linear feet of the boards or material, then enter the board width in inches. The calculator divides the width by 12 to express it in feet, then multiplies it by the linear length to give you the total square footage of coverage.
The Formula Explained
The core relationship is:
$$\text{square feet} = \frac{\text{linear feet} \times \text{width in inches}}{12}$$
Because area equals length times width, and width is given in inches, we divide by 12 (the number of inches in a foot) so both dimensions are in feet before multiplying.
Worked Example
Suppose you have 100 linear feet of boards that are 6 inches wide. First convert the width: \(6 \div 12 = 0.5\) ft. Then multiply: \(100 \times 0.5 = \mathbf{50}\) square feet of coverage. Equivalently, $$\frac{100 \times 6}{12} = \frac{600}{12} = 50 \text{ sq ft}.$$
FAQ
Why divide by 12? Width is entered in inches, and there are 12 inches in a foot. Dividing converts the width to feet so the multiplication yields square feet.
Can I use this for flooring? Yes. Add up the total linear feet of all the planks and enter the plank width to estimate the area they will cover. Always add a waste allowance of 5–10% for cuts.
What if my width is already in feet? Multiply the width in feet by 12 before entering it, or simply multiply linear feet by the width in feet directly.
