A 5x10 storage unit is the size of a small walk-in closet.
It fits furnishings of a mid-sized bedroom, including a queen-sized bed, a dresser, a TV and several small to medium-sized boxes.

A 10x10 storage unit is the size of half of a standard one-car garage. It fits the contents of an entire family room or two full bedrooms, including several small to medium-sized boxes.

A 10x15 storage unit is a little smaller than a standard one-car garage. It fits the contents of three full bedrooms and larger items such as a piano, couches, tables, or large-screen TVs, plus several medium to large-sized boxes.

A 10x20 storage unit is the size of a standard one-car garage.
It fits the contents of a multi-bedroom house, including several over sized items like a couch, a refrigerator, a washer/dryer and a dining room set or several large boxes.

Storage Unit Size. 10′ x 25′ / Approx 250 sq. ft. Extended one car garage. What Unit Will Hold. A 10' x 25' will fit the contents of a three bedroom house with appliances. This unit could also fit a large vehicle, small boat, and other large items with room to spare. Multiple bedroom sets, appliances, misc. boxes and large furniture