Storage facilities describe their units in floor dimensions, which is a slightly misleading way to sell a volume. A 10×10 unit is one hundred square feet of floor, but you are renting the air above it too, and how much of that air you use is what determines whether the unit is the right size.
Here is what actually fits in each common size, and what people typically get wrong.
The standard sizes
| Size | Rough comparison | Typical contents |
|---|---|---|
| 5 x 5 | A small closet | Seasonal decorations, a few boxes, a bicycle, small furniture. Roughly a dorm room’s worth. |
| 5 x 10 | A walk-in closet | The contents of a studio apartment without large appliances: mattress set, dresser, boxes, a chair. |
| 10 x 10 | Half a one-car garage | A one-bedroom apartment, or the furniture from two bedrooms plus boxes. |
| 10 x 15 | A large one-car garage | A two-bedroom home including major appliances. |
| 10 x 20 | A standard one-car garage | A three-bedroom home, or a vehicle, or a three-bedroom home minus the vehicle. |
| 10 x 30 | A two-car garage | A four- or five-bedroom home, or commercial inventory. |
Standard ceiling height is usually around eight feet, and some facilities go higher. Since almost nobody stacks all the way up, the practical usable volume tends to be less than the arithmetic suggests. Assume you will fill about seventy percent of the theoretical space unless you are unusually disciplined.
Estimating without guessing
The reliable method is boring: list your large items, then count your boxes.
Large furniture is what sets the floor area, because it generally cannot be stacked on top of anything and nothing stacks well on top of it. A sofa, a mattress set, a dining table, a dresser, a refrigerator. Count those first.
Boxes then fill the volume around and above them. A standard medium box occupies roughly three cubic feet. Fifty of them is 150 cubic feet, which is a stack about five feet high across a four-by-eight-foot area.
When you are genuinely between two sizes, take the larger one. The price difference between adjacent sizes is usually modest, and the alternative — discovering on loading day that a third of your belongings will not fit — is a considerably more expensive afternoon.
Loading it so you can still use it
How you load matters as much as what size you rent. A well-packed 10×10 holds more than a badly packed 10×15, and it stays accessible.
- Leave a center aisle. Roughly two feet down the middle. Every experienced storage user has this; every first-timer skips it and regrets it within a month.
- Heavy and rarely needed goes to the back. Appliances, furniture you will not touch until the unit closes.
- Anything you might want goes near the front. Be generous about what qualifies — you will want more than you expect.
- Build stable vertical stacks. Heaviest boxes on the bottom, uniform box sizes stacked together, nothing above shoulder height that you cannot lift down safely.
- Turn box labels toward the aisle. A perfectly organized unit whose labels all face the wall is not organized.
- Stand mattresses and sofas on edge against a wall, on a pallet or a plastic sheet rather than directly on concrete, and covered.
- Disassemble what disassembles. Table legs off, bed frames apart. Keep hardware in labeled bags taped to the piece.
- Keep everything off the floor. Pallets, boards, or plastic sheeting. Concrete transmits moisture and moisture finds cardboard.
Climate control: when it earns its cost
Climate-controlled units typically cost twenty to fifty percent more, and whether that premium is money well spent depends entirely on your climate and your contents.
Worth it for: wood furniture, especially antiques; anything upholstered or leather; electronics; photographs, documents, and artwork; musical instruments; vinyl records; and clothing you intend to wear again. Also worth it more or less regardless of contents in humid regions, and in areas with extreme summer heat where an uninsulated metal unit can exceed 120°F.
Not worth it for: tools, garden equipment, outdoor furniture, plastic storage bins, most sporting goods, and construction materials — in a mild, dry climate, for a short period.
The duration matters as much as the contents. Three summer months in Phoenix will do things to a leather sofa that three winter months in Portland will not.
Reading the contract before you sign it
- The promotional rate and what follows it. First month free, or a low introductory rate, is standard. Find out what the rate becomes, and when.
- How much notice is required to vacate. Often two weeks or a full month. Leaving without notice can cost you another month.
- Access hours. Twenty-four hour access is not universal. If you need to reach the unit at odd hours, confirm it.
- Insurance requirements. Most facilities require coverage. They will sell you a policy; check first whether your existing homeowner’s or renter’s policy already extends to off-site storage, since it often does at a reduced limit.
- Prohibited items. Universally: anything flammable, explosive, perishable, living, or illegal. Also, in most contracts, running a business from the unit.
- The lien process. Missed payments lead to the facility selling the contents, and the timeline is shorter than most people assume.
Choosing between facilities
Visit before you commit, and visit the actual unit rather than a display model. Look at the lighting, the cleanliness of the corridors, whether there is evidence of pest control, and whether the drive-up areas drain properly. Ask about camera coverage and whether the gate logs individual entry codes.
Ground floor with drive-up access is worth paying for if you will visit often or store anything heavy. Upper floors are cheaper and perfectly fine for boxes if the elevator is decent and carts are available.
One last piece of arithmetic that is worth doing honestly. Storage is a recurring cost with no end date unless you set one. Before you sign, add up twelve months of rent and compare it with the replacement cost of what you are storing. A surprising number of long-term units contain several thousand dollars of rent protecting a few hundred dollars of furniture, and nobody ever runs that comparison after the first year.