How to Choose a Storage Unit Size: A Practical Guide

Miles Mattingly
April 19th, 2025

Miles of Storage 401 Porterfield Ave, Richmond, IN 47374

When you're looking to rent a storage unit, one of the most common questions is: What size storage unit do I need? Pick something too small, and you’ll be frustrated trying to cram everything in. Go too big, and you could end up paying for unused space. Choosing the right storage unit size doesn’t have to be complicated. In this guide, we’ll break down the most common unit sizes, what they typically hold, and how to figure out exactly what you need based on your situation.

Step 1: Take Inventory of What You’re Storing

Before anything else, make a list of the items you plan to store. Are you storing a few boxes and small furniture, or an entire home’s worth of belongings? The more detailed your inventory, the easier it will be to estimate the space required.Things to consider:

Furniture (beds, couches, dressers, tables)
Appliances (washer, dryer, fridge)
Boxes and totes (count how many)
Specialty items (bicycles, lawnmowers, large mirrors, gym equipment)
Business inventory or seasonal items

Step 2: Understand Common Storage Unit Sizes and What Fits

Here’s a quick breakdown of the most common storage unit sizes and what typically fits in each:

5x5 (25 sq ft)

About the size of a small walk-in closet. Best for: Boxes, seasonal décor, small furniture, personal items.

5x10 (50 sq ft)

Fits the contents of a small studio or one-bedroom apartment. Best for: Mattress sets, dressers, TVs, chairs, and 10–15 boxes.

10x10 (100 sq ft)

Roughly half the size of a one-car garage. Best for: Contents of a one- or two-bedroom apartment including appliances, boxes, and medium furniture.

10x15 (150 sq ft)

Can hold the contents of a two- to three-bedroom apartment. Best for: Larger furniture sets, appliances, and 20+ boxes.

10x20 (200 sq ft)

Size of a standard one-car garage. Best for: A full three-bedroom home, or small vehicle storage.

10x30 (300 sq ft)

One of the largest standard sizes available. Best for: Contents of a four- to five-bedroom house or large equipment.

Step 3: Consider How You’ll Pack and Access Items

How you pack your items and whether you’ll need access to them affects the size you need.

Storing long-term with no access? You can pack the unit tightly from floor to ceiling.
Need regular access? Leave a clear aisle or space to move around.
Storing large or awkwardly shaped items? They may take up more room than you expect, especially if they can’t be stacked.

Tip: Use vertical space. Stack boxes and furniture when possible, and disassemble beds or tables to save space.

Step 4: Think About Future Additions

If there’s a chance you’ll need to store more items down the road, it might be worth going up one size to avoid having to move everything later. A 10x10 vs. 10x15 unit may be only a small price difference monthly but gives you added flexibility.

Step 5: Use a Storage Unit Size Calculator or Visual Aid

Many storage facility websites offer online calculators or visual guides where you can enter your item list and get a unit size recommendation. Some also show 3D mockups of what fits into each size.If you're unsure, visiting the facility in person and seeing a few empty units can help you visualize how much space you’ll really need.

Bonus Tips

Label everything and keep an inventory to maximize your organization inside the unit.
Choose uniform boxes for easier stacking.
Leave a small walkway if you'll need frequent access.
Climate control matters more than size if you’re storing sensitive items like clothing, electronics, or documents.

Final Thoughts

Choosing the right secure self storage in Indianapolis boils down to understanding how much you need to store and how often you’ll need access. Take inventory, look at size comparisons, and when in doubt, go slightly larger—especially if your belongings are valuable, fragile, or awkwardly shaped.Still not sure? Talk to the storage facility staff. They help people every day with similar needs and can offer size suggestions based on experience. With the right size unit, you’ll avoid headaches, save money, and keep your items safe and accessible.