What Size Storage Unit Do I Need? A Comprehensive Guide
—
November 27th, 2025
Most people search for “what size storage unit do I need” because they’re trying to avoid two things: wasting money on a space that’s too big or cramming everything into a space that’s too small. The truth is that choosing the right size gets much easier when you know how storage units actually work, how much they really hold, and how to estimate based on real situations rather than generic charts.
Some key takeaways for busy readers
This guide will give you a simple system for choosing the right unit without guessing, stressing, or making multiple trips. If you’re in a hurry and just want a rule of thumb, here’s what you need to know:
- A one-bedroom apartment usually fits into a 10x10 unit. Larger homes or multi-room moves usually need a 10x15 or 10x20.
- A 5x5 is fine for boxes and small items, but anything involving furniture almost always requires at least a 5x10.
- Plan for a 15 percent buffer. Almost everyone ends up with more items than expected.
- If you will access your unit often, you need space for an aisle. That usually means choosing the next size up.
- Vertical space matters. Most units are eight feet tall, which gives you stacking room and can let you pick a smaller unit if your items stack safely.
- Drive-up units make loading, unloading, and long-term storage easier, especially for larger units.
Now that you know the basics, let’s break down the details that most storage providers will never tell you.
1. Start by looking at what you’re storing
The quickest way to figure out what size storage unit you need is to divide your belongings into three categories. First, items that can stack. Second, items that cannot stack. Third, long items that take up horizontal space.
This matters because most people underestimate how high they can safely stack boxes. According to the International Association of CHI, standard moving boxes can usually be stacked safely between three and five levels if they are packed correctly and the bottom ones are sturdy. This gives you a pretty good sense of how to plan your footprint.
Anything odd-shaped, fragile, or heavy should be placed lower, so you want to plan for a grid rather than random piles. This alone reduces the chance you’ll choose a unit that is too small.
2. Think in terms of rooms instead of boxes
Homeowners and renters consistently misjudge volume because they look at boxes instead of full rooms. A bedroom's worth of items looks small when packed, but once you add furniture, bins, holiday decor, and awkward items like lamps and fans, you are suddenly dealing with a much larger footprint.
Here is a more reliable way to think about it. A typical one-bedroom apartment usually fills a 10x10 storage unit comfortably, but only if you pack with intention and leave a walkway. A two-bedroom apartment generally fits into a 10x15 or 10x20, depending on how much furniture you have.
The majority of residential renters choose between 50 and 150 square feet, so think about where you fall on that scale.
For instance, our customers at Foothill Mini Storage often show up expecting a smaller space, then quickly realize that beds, sofas, patio sets, and appliances take up more room than planned.
3. Visualize the footprint on the ground
Before you settle on a size, take painter’s tape and map the dimensions on your garage floor or driveway. For example, a 5x10 is the size of a walk-in closet. A 10x10 is roughly half of a standard one-car garage. A 10x20 is similar to a full one-car garage.
This quick exercise helps you understand real spacing. Many customers who do this realize they need more walking space inside the unit, especially if they will be in and out often. This is one of the strongest indicators that a slightly larger unit will save time, headaches, and money in the long run.
4. Consider how often you will access your items
If you only plan to load the unit once and leave it for six months, you can pack it tightly. If you need weekly access, you must plan for aisles, which immediately changes the size you’ll need.
At Foothill Mini Storage, we see this pattern constantly. Contractors storing tools prefer 10x15 or 10x20 units because they want fast access. Families storing seasonal items prefer 10x10 units with organized shelving. People between homes often choose 10x20 units so everything fits in one trip and stays accessible.
Your access frequency is just as important as your inventory when choosing the right unit.
5. Understand common storage sizes & what they actually hold
While this isn’t a chart, it helps to have a reference point.
A 5x5 is best for boxes, small furniture, sports gear, or holiday items. A 5x10 works for a studio apartment or one small room. A 10x10 handles a one-bedroom apartment. A 10x15 handles a larger apartment or a small home.
A 10x20 is the most flexible for two to three bedrooms' worth of belongings. And a 10x30 is ideal when you need to store multiple rooms plus larger items like appliances or business inventory.
One practical thing to keep in mind is that local facilities vary. For example, Foothill Mini Storage offers drive-up units, plus individually alarmed new units that work well for people storing valuables or business items. Security and convenience matter as much as size because the wrong environment can cause you to move items twice.
6. Check how fragile or sensitive your items are
If you’re storing instruments, electronics, antiques, wood furniture, or anything sensitive to quick temperature changes, you want to plan your packing strategy more carefully. Even in a mild-climate area like Cameron Park, stacking rules change when fragile items are involved.
The Federal Emergency Management Agency advises keeping sensitive materials elevated, wrapped, and away from direct contact with concrete.
If you know you need extra padding, shelving, or space for protective materials, this widens the footprint inside the unit. This can bump you from a 5x10 to a 10x10 without you realizing it.
7. Look at height, not only floor space
Many customers underestimate how much vertical space can save them. Most storage units have an eight-foot ceiling. That is a lot of stacking potential, especially for boxes, mattresses, and lightweight furniture.
Once you understand this, you can confidently choose between two close sizes.
For example, a 10x10 with vertical stacking might hold everything you planned to put in a 10x15. You may be able to choose the smaller size if your belongings stack safely and you won’t be accessing them every week.
8. Use the 15 percent buffer rule
Even if you’re great at estimating, you will almost always end up with more items than expected. Homeowners usually underestimate by about 10 to 20 percent during moves and renovations. This is why the most reliable approach is to add at least 15 percent breathing room to your estimate.
If you think you can squeeze into a 10x10, but you have bulky items or expect to access things regularly, stepping up to a 10x15 often prevents a second rental or an unplanned upgrade.
This simple rule works for almost every scenario, and you will rarely regret having a bit more space.
Final thoughts
Choosing the right size storage unit becomes simple once you understand your inventory, access needs, stacking limits, and available space. When you take the time to measure, visualize, and plan for 15 percent more volume than expected, you avoid wasted trips, surprise upgrades, and last-minute scrambling.
If you’re around Cameron Park and want help choosing the right size in person, Foothill Mini Storage is right off Highway 50 with clean, secure, locally managed units that make loading and storing faster and safer. Our team can walk you through your options and help you choose the right space without overpaying.
Categories