Measuring length and depth may be required if you're in the process of laying cement for a project outdoors. Likewise, you may also need to know the length and depth of an area if you're buying mulch, soil or some other type of supply for outdoor use. You can measure length with depth in just a few minutes using a regular tape measure.
Determine which measurement of your object is actually the depth. This depends on the type of object. For example, the depth of a concrete slab would be from the surface of the slab to the bottom where the slab meets the ground. However, the depth of a television set would be the distance from the front of the screen to the back of the unit.
Place your tape measure on the surface of the object you're measuring and stretch it across to the back or bottom of the object to measure its depth. Write this number down. It is the measured depth of the object.
Measure the length of your object by placing the tape measure at one end and stretching it across to the other. For example, on a television set the length would be measured from the left side of the unit to the right side. However, on a concrete driveway, the length would be measured from the front of the driveway where it meets the road to the opposite end. Write this number down. It is the measured length of the object.