Storage unit sizes
Researched and written by Ashley Davis · Reviewed by Emily Johnson · Last reviewed August 2026
Standard storage units come in five footprints and the arithmetic is simple, because the size is the measurement. A five by five is 25 square feet, a five by ten is 50, a ten by ten is 100, a ten by fifteen is 150 and a ten by twenty is 200. Ceilings are usually eight feet, so a unit holds more than its floor area suggests if it is loaded to height. Room count is the usual way to translate: a studio into a five by ten, a two-bedroom into a ten by ten, a full family house into a ten by twenty.
What are the standard storage unit sizes?
Five, and they repeat across almost every operator because they are laid out on the same building grid. Five by five, which is 25 square feet and the size of a small closet. Five by ten, 50 square feet, roughly a walk-in closet. Ten by ten, 100 square feet, half a single garage. Ten by fifteen, 150 square feet. Ten by twenty, 200 square feet, which is a standard single garage. Some sites also offer a ten by thirty at 300 square feet and lockers below the five by five.
How tall is a storage unit?
Eight feet is the usual interior height, and drive-up units are often the same. That matters because capacity is volume rather than area: a ten by ten loaded to seven feet holds close to twice what the same unit holds loaded to shoulder height. The practical limit is not the ceiling but what can be stacked safely, which is why heavy boxes go at the bottom and nothing fragile carries weight above it.
Which size matches which home?
As a working translation, and it is a starting point rather than a rule. A five by five takes seasonal items, boxes and a few small pieces. A five by ten takes the contents of a studio or one bedroom. A ten by ten takes a one or two bedroom apartment including appliances. A ten by fifteen takes a small house of two or three bedrooms. A ten by twenty takes three or four bedrooms, which is most of a family house.
Should you take the larger unit?
Size for how you will use it. If the unit is loaded once and opened at the end, pack to the walls and take the smaller footprint. If you will retrieve things during the stay, the next size up buys a walkway down the middle, and a unit with no aisle is a unit that gets unloaded onto the corridor floor every time you need one box. The packing a storage unit page sets out both layouts.
How do you check a size rather than guess it?
Measure the four largest pieces and the total box count, then compare against the footprint. A sofa, a mattress set, a fridge and a dining table decide the unit far more than the boxes do, because boxes fill gaps and furniture does not. Most operators will let you look at an empty unit of each size before you sign, which is worth more than any online calculator.