What Size Storage Unit Do I Need? A Simple Sizing Guide
If you’re asking what size storage unit do I need, the honest answer is that most people rent one size too big and pay for the extra space for years. A 10×10 unit runs about $100 to $200 a month in most cities, and the difference between a 10×10 and a 5×10 can be a thousand dollars over a couple of years. I help people move and sell big household items for a living, so I’ve stood in a lot of half-empty storage units doing the math out loud with the person renting them. The space almost always could have been smaller.
So this guide does two things. First, it’ll get you to the right storage unit size with a clear breakdown of what actually fits in each one, from a 5×5 closet up to a 10×30 garage. Second, it’ll make you ask the better question hiding underneath this one: how much of what you’re about to store do you actually want back? Let’s size the unit, and let’s also be honest about the stuff going into it.
What size storage unit do I need? Start with what you’re storing
The right storage unit size depends on volume, not square footage of your home. A studio apartment and a three-bedroom house can need the same unit if one person purged and the other kept everything.
Storage units are sold by floor footprint, but they’re usually 8 feet tall, so you’re really renting a cube of air. A 10×10 isn’t 100 square feet of usable space, it’s closer to 800 cubic feet if you stack well. Most people never use the top third. So before you pick a size, picture the actual pile: the couch, the mattress, the boxes, the bikes, the holiday bins. Group it in your head into “big furniture,” “boxes,” and “awkward stuff” (lamps, mirrors, the treadmill). That mental inventory is what sizes the unit, and it’s also the moment you realize how much of it you’re storing out of habit rather than need.
Storage unit sizes and what fits in each
Here’s the quick version: 5×5 is a closet, 5×10 is a studio, 10×10 is a one-bedroom, 10×15 is a two-bedroom, 10×20 is a small house or a one-car garage, and 10×30 is a full house or a car plus belongings.
This is the table I wish every storage company put on the wall before you sign:
| Unit size | Rough equivalent | What fits | Typical monthly cost |
|---|---|---|---|
| 5×5 | A large closet | Boxes, small furniture, seasonal gear, a mattress set on edge | $40 to $75 |
| 5×10 | A walk-in closet / studio | Contents of a studio: bed, dresser, boxes, a few small items | $60 to $110 |
| 10×10 | A one-bedroom apartment | Couch, queen bed, dresser, table, plus 10 to 15 boxes | $100 to $200 |
| 10×15 | A two-bedroom home | Two bedrooms of furniture, appliances, boxes, a bike or two | $140 to $250 |
| 10×20 | A small house or one-car garage | Three-bedroom home contents, major appliances, or a car | $170 to $300 |
| 10×30 | A full house plus a vehicle | Four-plus bedrooms, large appliances, a car and belongings | $225 to $400 |
Prices swing hard by city and by whether the unit is climate controlled. The point isn’t the exact number, it’s the jump between sizes. Every step up is another $40 to $100 a month, forever, until you empty it. If you want a deeper price breakdown by region and unit type, I put that in our guide on how much a storage unit costs.
How to estimate your storage unit size without guessing
The most reliable way to size a unit is to count your big items and your boxes, then match that to the table above. Furniture sets the floor space, boxes fill the cube.
Walk through your place and tally it like this. Big furniture sets the size: a sofa and a bed alone push you toward a 10×10. Then estimate boxes in groups of ten. A one-bedroom usually generates 10 to 20 boxes once everything’s packed. Appliances, mattresses, and “awkward stuff” each eat more room than you think, because you can’t stack neatly around them.
- List your large furniture. Sofas, beds, dressers, tables, desks.
- Count appliances. Fridge, washer, dryer each take real floor space.
- Estimate boxes in tens. Round up, never down.
- Add the awkward items. Mirrors, lamps, bikes, fitness gear, headboards.
- Match to the table, then ask if you can drop a size by selling a few things.
That last step is where the real savings hide. Dropping from a 10×15 to a 10×10 because you sold a spare couch and a dresser can pay for itself in two months, and you pocket the sale on top.
Should you pay to store it, or sell it?
Here’s the question I actually want you to sit with: if you’re paying to store something, you should be sure you’ll want it back at today’s prices. A lot of stored furniture is worth less than the rent it racks up.
Run the numbers. Say you’re storing a sectional, a guest bed, and a treadmill in a 10×10 at $150 a month. After a year, that’s $1,800 to keep items that might sell for $1,200 combined right now. You’re paying to lose money. Storage makes sense for things you’re genuinely between-homes with, or for irreplaceable items. It rarely makes sense for replaceable furniture you’re storing “just in case.” If you’ve ever wondered how much you can make reselling furniture, the answer is usually more than you’d guess, and definitely more than storing it costs you.
The big stuff is exactly what makes storage expensive and exactly what’s a pain to sell the old way. That’s the gap we built Commonplace to close. You list the heavy item, and when it sells, a driver comes and picks it up, so you’re not renting a truck or wrangling a sleeper sofa down a stairwell to make a sale. Buyers get a window to inspect it before they pay, which is why big used items actually move on the platform. Here’s how it works. Sell the three things you don’t really want back, drop a unit size, and the storage math flips in your favor.
How to pack a storage unit so you need less space
Smart packing can save you a whole unit size. Most people waste a third of their unit by not stacking and not planning a path to the back.
Disassemble what you can. Bed frames, table legs, and shelving break down flat and reclaim huge amounts of floor. Stand mattresses and sofas on end against the walls. Use uniform boxes so they stack square and tall, heaviest on the bottom, and fill them completely so they don’t crush. Put the cube to work: storage units are tall, so build upward, not outward. And leave a narrow walkway to the back so you can reach anything without unloading the front. If you’re storing furniture you eventually want to sell or ship, pack it to protect the finish, the same way you would to ship furniture without damage, because scuffs in storage cost you at resale.
Climate control, access, and the costs people forget
Climate control matters for wood, leather, electronics, and anything you plan to resell, and it usually adds 25 to 50 percent to the price. Whether it’s worth it comes down to what’s inside and how long it’s staying.
Heat and humidity warp wood, crack leather, and grow mold on upholstery. If you’re storing a solid-wood dresser or a leather sofa for more than a season, climate control protects the resale value you’re trying to preserve. For a few boxes of dishes over a short move, standard is fine. Two other costs sneak up on people: drive-up versus interior access (interior units mean carrying everything down a hallway), and the long-term creep of “temporary” storage that quietly turns into three years. Set a hard end date when you rent. If you hit it and you still haven’t missed half the unit, that’s your sign to sell the contents rather than re-up. The cleaner those items are, the more they bring, which is why I always tell people to wipe things down before they list, the same logic as our piece on how to sell furniture online.
Frequently asked questions
What size storage unit do I need for a one-bedroom apartment?
A 10×10 unit fits most one-bedroom apartments: a couch, a queen bed, a dresser, a small table, and 10 to 15 boxes. If you’ve purged or you’re storing only part of the apartment, a 5×10 often does the job for less money.
What size storage unit do I need for a 3-bedroom house?
Plan on a 10×20 for a typical three-bedroom house, which holds the contents of three bedrooms plus major appliances and boxes. A heavily furnished home or one with a lot of bulky items may push you to a 10×30.
Is it cheaper to get a bigger unit or two small ones?
One right-sized unit is almost always cheaper than two small ones once you add up two sets of base rent. The bigger savings, though, is renting smaller in the first place by selling the items you don’t truly need to keep.
How tall are storage units?
Most storage units are about 8 feet tall, and some go higher. That vertical space is the part people waste most. Stacking boxes and standing furniture on end can effectively give you a size larger than the floor plan suggests.
Should I sell my furniture instead of storing it?
Usually yes, if it’s replaceable furniture you’re keeping “just in case.” Storing a unit of furniture for a year often costs more than the furniture would sell for today. Storage makes sense for irreplaceable items or genuine between-homes situations, not for delaying a decision.
So, what size storage unit do you need? Count the big furniture, estimate your boxes in tens, match it to the table, then try to drop one size by selling what you won’t miss. The unit you don’t rent is the cheapest one there is. When you’re ready to lighten the load, price the big items honestly and let a driver handle the pickup, so downsizing your storage doesn’t mean a weekend of hauling.