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You've visualized, you've pulled out a measuring tape, maybe you got really creative and attempted a Sims recreation, but still, you just don't know what size storage unit you need. It feels high stakes. You don't want to be paying for empty space if you choose too big, but on the other hand, you don't want to be worried about falling boxes if you've chosen too small.
The goal is to find the "Goldilocks" zone—the space that fits your belongings just right. This guide breaks down the most common storage unit sizes, what fits inside them, and how to estimate the space you need.
What To Ask Yourself Before You Rent
Before you even consider storage unit sizes, determine exactly what it is you are storing.
1. What Are You Storing?
A few boxes of holiday decorations won't need the same space as the contents of a 4-bedroom house. Try to be objective. How bulky are your items?
2. How Often Will You Need Access?
If you need your belongings daily or even weekly, you'll need to make it easy to reach them. Allow a little extra space to create walkways. If you’re packing it away for a year and won’t touch it, you can rent a smaller size.
Storage Unit Size Breakdown
Now that you've established what you are storing, take a look at standard storage unit sizes and what they can hold.
Small Units
5x5 Unit (25 sq. ft.) – The "Hall Closet"
This is perfect for decluttering or storing off-season items.
Best for: 10–15 medium moving boxes, seasonal décor, personal items, and small furniture like a nightstand, lamps, or chair.
Not suited for: Mattresses (unless child or twin size), couches, or large appliances.
5x10 Unit (50 sq. ft.) – The "Walk-In Closet"
Students may be familiar with this one. Also perfect for people decluttering a specific room.
Fits: The contents of a studio apartment or a dorm room.
Specific examples: A queen mattress set (stored upright), a dresser, a TV, a bike, and 10–15 medium boxes.
Medium Units
10x10 Unit (100 sq. ft.) – The "Small Bedroom"
Ideal for a standard one-bedroom apartment move.
Fits: A one-bedroom apartment’s worth of furniture and goods.
Specific examples: A king-sized mattress, a couch, a refrigerator, a washer/dryer, a dining set, and 20–30 medium boxes.
10x15 Unit (150 sq. ft.) – The "Large Bedroom"
This unit is a great size for a two-bedroom apartment or a small house.
Fits: The contents of a condo or two-bedroom apartment.
Specific examples: Multiple bedroom sets, living room furniture (sofas, armchairs), major appliances, and large items like pianos or business inventory/shelving.
Large Units
10x20 Unit (200 sq. ft.) – The "One-Car Garage"
This unit can handle a full family move.
Fits: A three-bedroom home or a vehicle.
Specific examples: A car or small truck, plus furniture. Alternatively, it holds the contents of a 3-4 bedroom house, including appliances, patio furniture, and dozens of boxes. It’s also a good fit for contractor tools and equipment.
10x30 Unit (300 sq. ft.) – The "Extra Large Garage"
The largest standard size available.
Fits: A 4+ bedroom home or significant commercial inventory.
Specific examples: A vehicle plus multiple rooms of furniture, large commercial equipment, or the contents of a large moving truck.
Do You Need Climate Control?
Storage unit sizes are important, but don't forget to consider the environment inside the unit, especially in coastal areas like Newport Beach, California, where moisture can have a huge impact on the longevity of your items.
Climate-controlled units create a stable temperature range and humidity level. Essential if you are storing:
Electronics or appliances
Wood or leather furniture (prone to cracking or warping)
Important documents or photographs
Artwork or musical instruments
Clothing and fabrics
Common Mistakes and How To Avoid Them
Guessing based on square footage alone: A 5x5 storage unit will feel bigger than a 5x5 room. Take the time to measure and plan out how your items will be stored in the unit.
Forgetting to clear a path: Paths are great for access, but they are also another way to introduce airflow—preventing mustiness and mold growth.
Ignoring ceiling height: Most units have 8-foot ceilings or higher. If you can stack safely, you can pack more than you think. You can also get creative and use wall space for mounting bikes or other sports equipment.
Packing like a moving truck: A moving truck is packed tightly so items don't fall. A storage unit should be packed for access.
Figure Out the Space You Need in 10 Minutes
4 tips that are better than a calculator:
Count the furniture: List your large items first (beds, sofas, tables). These determine the minimum square footage you need.
Estimate boxes: Visualizing the space in "banker boxes" (standard file boxes) helps.
Add 20% for "breathing room": If your math says you need exactly 50 square feet, bump it to 60.
Consider shelving: Metal shelving units can double your storage capacity for boxes and loose items.
Ask us: At Purely Storage, we've seen many a storage unit filled, and can help you find the right size.
Find the Right Fit With Purely Storage
Make note of what you need to store, pack strategically, and you can find the unit that perfectly fits your needs.
If you still need help visualizing the space or have questions about a particular item, don't hesitate to contact us. For those near Newport Beach, an on-site visit to a facility, such as the one on Campus Drive, can instantly clarify whether your sofa (or other large items) will fit and help you decide on the different storage unit sizes. At Purely Storage, our month-to-month contracts let you scale up or down as your needs change.
Call us today to talk about storage unit sizes.
