Storage Unit Size Guide: Find Your Perfect Fit (2025)

Picking a storage unit size is the worst. It’s all numbers and you have no idea what they mean. Is a 10×10 big? Is it small? It’s just a math problem when you’re already stressed out.

I don’t own a storage company. But I’ve moved a bunch of times. I’ve rented the wrong size. I’ve stood in an empty unit that looked like a football field, only to fill it up in an hour and have to call the guy back to ask for a bigger one. It’s embarrassing.

So here’s the no-BS guide from someone who’s messed it up so you don’t have to.

First, your couch is the key

Go look at it. Is it a big sectional? A small loveseat? That thing is your ruler. Everything else fits around it.

Now, let’s forget the numbers and think in real life stuff.

The “Big Closet” Size (they call it a 5×5)

This is what you get when your apartment closet is vomiting clothes and you need to stash your winter coats in July. You can fit a mattress, a dresser, and a bunch of those cardboard boxes you stole from the grocery store. It’s tight. You cannot fit a couch. Don’t even try. You’ll just get the couch stuck in the door and curse a lot.

The “I’m Between Apartments” Size (this is a 5×10)

This one feels like a real, tiny room. You can walk in and not panic. This will hold all the junk from your one-bedroom apartment. Your bed, your couch, your dumb coffee table, your kitchen table, and all the boxes you packed while watching Netflix. You can even put a bike in the corner. This is the most common size for people who are normal-level messy and moving.

The “Oh Crap, I Have a Whole House” Size (the 10×10)

This looks huge. Like, “I could have a dance party in here” huge. Then you put your stuff in and it suddenly feels very, very small. This is for people with a family. It holds the contents of a two or three-bedroom house. You have to stack boxes to the ceiling. The trick is to put the heaviest, sturdiest stuff on the bottom. If you stack a box of pillows on top of a box of your mom’s fine china, you’re gonna have a bad time.

Then there are the bigger ones, for cars and boats and people who own a lot of furniture. You’ll know if you need that.

Here are my personal tips from getting it wrong:

1. Take stuff apart. That bed frame? The table legs? A screwdriver is your best friend. It creates so much more space.
2. Label your boxes like a crazy person. “Kitchen” is useless. Write “KITCHEN – coffee maker, spatulas, and the good wine glasses.” You will thank yourself later when you’re looking for the coffee maker at 7 AM.
3. Make a path. If you pack it wall-to-wall, you’ll have to unpack everything to get the one thing you need from the back. It’s a nightmare.

But honestly, the best advice I can give you is to just talk to the people at the storage place. A real one, not some online chatbot.

The Bottom Line

I remember the last time I moved, I called a place called HarrisonBurg Storage. I told the guy on the phone, “I have a queen bed, a big couch, a bookshelf, and like… I don’t know, a million boxes?” And he said, “Yeah, you need the 10×10. The 5×10 will be too tight.” He was right. He saved me a trip.

So if you’re using HarrisonBurg Storage, just call them. Tell them what you’ve got. They’ve seen it all. They’ll know. It’s way easier than trying to guess on your own and ending up like I did, sweating and trying to force a bookshelf into a space that’s two inches too small.

Just call them. It’s the easiest way to not mess it up.