What Size Storage Unit Do I Need?

Tell us your home size or the things you're storing and we'll estimate the right storage unit — 5×5 up to 10×30 — with what each size actually holds.

Updated 2026-08-06 · Free tool · No sign-up · Runs in your browser

How this tool works

Every result is driven by volume in cubic feet, not floor space — because you stack a storage unit to the ceiling. We estimate the cubic feet of what you're storing, then find the smallest standard unit whose usable volume can hold it.

  • Your load = the typical contents of the home size you pick (if any) plus any extra items you list. Home sizes already include ordinary furniture, so only add items you're storing on top of a normal household.
  • Usable volume = the unit's raw volume (floor area × an 8-ft ceiling) times a packing factor. We use about 78% when you pack it solid, and about 58% when you need an aisle to reach the back — real people never fill 100% of a cube.
  • Room to spare / Packed full / Too small — a unit is "room to spare" with ~15%+ headroom, "packed full" when your load fits but nearly fills it, and "too small" when it can't hold your load.

The recommended size is the smallest unit that fits. If it comes back "packed full," we suggest the next size up so you can actually get to your things. Standard sizes assume an 8-ft ceiling; a few facilities offer taller units.

Caveat: this is an estimate. How well you disassemble beds, nest chairs and stack boxes can shift you a size in either direction. Confirm the interior dimensions and door size with the facility before booking.

Standard self-storage unit sizes and what they hold (7 sizes)

Floor area, volume (at an 8-ft ceiling), and typical contents for each standard unit. Last updated 2026-08-06. Medium-high. Standard unit footprints are consistent across the major operators; the contents-to-size mapping is an industry rule of thumb and depends heavily on how well you stack. Units are assumed to have an 8-ft ceiling.

Unit sizeFloor areaVolume (8-ft ceiling)Roughly equalsTypically holds
5×525 sq ft200 cu ftA large closetA few boxes, small furniture, and seasonal, dorm or office items — about the contents of a large closet.
5×1050 sq ft400 cu ftStudio / small 1-bedroomThe contents of a studio or small one-bedroom without big appliances — a mattress set, a dresser, and roughly 15–20 boxes.
5×1575 sq ft600 cu ft1-bedroom apartmentA full one-bedroom apartment with some appliances — sofa, mattress set, a few furniture pieces and boxes.
10×10100 sq ft800 cu ft2-bedroom apartment or houseThe furnishings of a two-bedroom apartment or small house — two bedrooms of furniture, appliances and boxes.
10×15150 sq ft1200 cu ft2–3 bedroom homeA two-to-three-bedroom home — major furniture, appliances, and the contents of several rooms.
10×20200 sq ft1600 cu ft3–4 bedroom houseA three-to-four-bedroom house, or a one-car garage's worth of belongings, appliances included.
10×30300 sq ft2400 cu ft4–5 bedroom houseThe largest standard unit — a four-to-five-bedroom house, roughly a two-car garage of contents.

Sizes and contents compiled from Public Storage, Extra Space Storage, CubeSmart and U-Haul size guides. Contents are a rule of thumb — actual capacity depends on how you pack.

FAQ

How is this different from picking a size off the storage company's chart?

Those charts show one home size per unit. This adds up the actual cubic feet of what you're storing — including the extra boxes or furniture you list on top of a home — and accounts for whether you need a walkway, so the estimate matches your stuff, not an average.

Why does needing an aisle bump me to a bigger unit?

If you have to reach items in the back you can't pack the cube solid — you lose roughly a third of the space to the aisle. We size up so the unit you rent actually works the way you'll use it.

My home is furnished — do I still add my sofa and bed as extra items?

No. The home sizes already include normal furniture. Only add items in the 'extra' fields if you're storing more than a typical household — like a second sofa, garage overflow, or a pile of extra boxes.

What does a 10×10 unit actually hold?

Roughly a two-bedroom apartment or small house — about two bedrooms of furniture, appliances and boxes. See the full size table on this page for what each standard size holds.

Do the numbers assume a tall ceiling?

They assume the standard 8-foot ceiling and that you stack toward it. Some facilities offer taller units; if yours does, you'll fit a bit more than the estimate shows.

How accurate is the estimate?

It's a solid starting point built from the major operators' size guides and moving-industry volume tables, but real capacity swings with how well you pack. Treat 'packed full' as a nudge to book the next size up, and confirm dimensions with the facility.

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