Unlike a square foot (which is a square with sides equaling 12 inches), a linear foot is just 12 inches in a straight line traveling in any direction. If you want to determine the number of linear feet in the length, width or height of an object, you can do so in a few minutes with any regular tape measure you happen to have access to.
Things You'll Need
 Tape measure

Lay the beginning of a tape measure at the point where you want your linear foot measurement to start. If you're measuring the height of something, for example, this end of the tape measure would rest on the floor.

Stretch out your tape measure so that it reaches the end point of your measurement. If you're measuring the height of a table, for example, the end point would be the surface of the table.

Look at how many feet are between your two points as displayed on the tape measure. If your table is 3 feet off the ground, your measurement would be 3 linear feet.