Key Takeaways
- Start by listing your largest items — do not guess square footage
- Plan for a center aisle if you will access the unit regularly
- A 10x10 unit holds the contents of a small one-bedroom apartment
- Go one size up if your situation is still changing
Choosing the right storage unit starts with a simple question: what are you storing now, and what might you add in the next three to six months? Many renters pay more than they need to because they guess instead of planning. Others choose too small a unit and end up cramming belongings in with no room to move.
Before you reserve a unit, make a quick list of your biggest items first: mattresses, couches, appliances, desks, and any boxed inventory. Then estimate the number of medium boxes and note whether you need walking space to access items regularly.
This guide walks you through a straightforward process so you can rent confidently, avoid overpaying, and still have room for everything you need to store.
Start with access needs, not just square footage
The way you plan to use your unit matters just as much as what goes inside it. If you will open the unit frequently — say, once a week or more — plan for a small center aisle. If you are storing items for a longer period with minimal access, you can stack more tightly and use less floor space.
- Frequent access: Leave an aisle down the middle and label boxes on at least two sides. Plan to retrieve items without unstacking entire walls of boxes. Use shelving units if possible.
- Long-term storage: Stack safely to the ceiling and place heavy items on the bottom. Use uniform box sizes for stable stacking. Wrap furniture in protective covers before placing items against it.
- Mixed storage: Keep seasonal items near the front for quick swaps. Store rarely-needed items toward the back wall. This hybrid approach saves floor space while keeping essentials easy to reach.
Pro Tip
Take a photo of your unit layout on move-in day. This makes it much easier to find specific items during future visits — especially after several months have passed. Keep the photo on your phone for quick reference.
Common unit sizes at a glance
Most storage facilities offer a standard range of sizes. Here is a quick comparison to help you estimate what works for your belongings.
| Unit Size | Square Feet | Best For | Fits Roughly |
|---|---|---|---|
| 5x5 | 25 sq ft | Small items, boxes, seasonal gear | Walk-in closet worth of items |
| 5x10 | 50 sq ft | One room of furniture plus boxes | Mattress set, dresser, several boxes |
| 10x10 | 100 sq ft | One-bedroom apartment contents | Full living room and bedroom set |
| 10x15 | 150 sq ft | Two-bedroom apartment | Appliances, furniture, 20+ boxes |
| 10x20 | 200 sq ft | Three-bedroom house contents | Large furniture, appliances, many boxes |
| 10x30 | 300 sq ft | Whole house or business inventory | Vehicles, large equipment, full households |
Keep in mind that ceiling height also matters. Most units have eight-foot ceilings, which means you can stack boxes and furniture vertically to make better use of the space. Taller units — sometimes ten feet — are available at some facilities.
Measure the largest items first
Measure length, width, and height for oversized items. This helps prevent surprises on move-in day and makes it easier to compare unit options at different facilities.
Pay special attention to couches, mattresses, and large tables. These bulky items often determine your minimum unit size. A king mattress alone is roughly 6.5 feet by 6.5 feet when laid flat, which takes up a significant portion of a 5x10 unit. Standing the mattress on its side with a protective cover can free up valuable floor space.
If you need help visualizing dimensions, visit our storage size guide to compare common unit footprints side by side.
Quick Math
To estimate the total cubic feet you need, multiply the length x width x height of each large item and add them together. Divide by the unit ceiling height (usually 8 feet) to get the approximate floor space required. Add 15-20% extra for walking space and air circulation.
Leave room for future life changes
People often rent storage during moves, renovations, downsizing, or business growth. If your situation is still changing, choose a unit with a little extra capacity so you are not forced to move again in a few weeks.
A good rule of thumb: if you think a 10x10 will be tight, step up to a 10x15. The monthly cost difference is usually modest compared to the hassle of renting a second unit or transferring everything to a larger one later. Most facilities will let you switch sizes if availability allows, but the physical effort of re-packing and moving is something you want to avoid.
What about climate-controlled units?
If you are storing temperature-sensitive items like wood furniture, electronics, or documents, consider a climate-controlled unit. The size selection process is the same, but climate-controlled units are typically interior-access and may have slightly different ceiling heights. They are worth the extra cost for items that can warp, crack, or degrade under extreme heat or humidity.
Common Mistake
Do not assume you can fit everything into the smallest unit available. Overpacking leads to damaged items, difficulty accessing stored goods, and potential safety hazards from unstable stacking. When in doubt, go one size up.
Packing to maximize your space
Once you have chosen the right size, how you pack the unit makes a big difference. Disassemble furniture when possible — remove table legs, take apart bed frames, and detach shelving. Use wardrobe boxes for hanging clothes instead of laying them flat. Fill dresser drawers with soft items like towels and linens.
For a complete breakdown of packing strategies, see our guide on packing tips for long-term storage.
When you are ready, browse available options by facility on our all locations page and compare what works best for your needs.
Frequently Asked Questions
What size storage unit do I need for a one-bedroom apartment?
A 10x10 unit (100 square feet) typically fits the contents of a one-bedroom apartment, including a bed, couch, dining set, and 10-15 boxes. If you have especially bulky furniture or appliances, consider a 10x15.
Can I change my unit size after move-in?
Yes. Most Flex Storage facilities allow you to transfer to a different size unit based on availability. Contact your facility manager to arrange a size change — they can often schedule a smooth same-day transfer.
Is it better to rent a slightly larger unit than I think I need?
In most cases, yes. A slightly larger unit gives you room to organize, create aisles for access, and accommodate items you did not originally plan to store. The cost difference between adjacent sizes is usually small.
How do I know if I need a drive-up unit vs. interior access?
Drive-up units work best for heavy or bulky items, vehicles, and frequent loading and unloading. Interior-access units are typically more secure and available with climate control, making them better for valuables and long-term storage.