How to Calculate Inches Into Linear Feet
The short answer is that there are 12 inches in one foot, but this question often arises in measuring lumber and counter tops, so a longer answer might be more useful. Lumber is often sold in units called “board feet” and counter tops are marketed in linear inches but priced in square feet. There are four concepts to keep in mind. “Cubic” refers to a measurement that is the product of height multiplied by width multiplied by length. “Square” refers to a measurement that is the product of width multiplied by length. “Linear” simply refers to the length of anything, like a board of any size. And, “board feet” refers to the volume of a board in cubic inches divided by 144.
Sort 12 8-feet-long two-by-fours, six 8-feet-long 1-by-8s and two 8-feet-long 4-by-4s into three piles with one kind of board in each pile.
Calculate the linear feet of all this lumber and continue to calculate until you arrive at 160 linear feet. You have 20 boards that are all 8 feet long and 20 multiplied by 8 yields 160. You also have 1,920 board inches in the three piles because 160 multiplied by 12 equals 1,920.
Calculate the board feet in the pile of two-by-fours by multiplying the nominal, not actual, dimension of any two-by-four (8) by the length in inches (96), then by the number of boards (12) divided by the number of square inches in one square foot (144). You have 64 board feet of two-by-fours.
Measure the width of a 120-inch-long counter top you would like to buy. Counter tops are typically sold by the square foot and are frequently 32 inches wide.
Multiply 120 by, for example, 32. This yields 3,840 square inches. Divide 3,840 by 144 to determine that you would like to buy a 2666-square-foot counter top.