10×20 storage unit vs 10×30 storage unit
A 10×20 storage unit gives 200 square feet (sq ft) and about 1,600 cubic feet (cu ft); a 10×30 storage unit gives 300 sq ft and 2,400 cu ft. Choose the 10×20 storage unit if your inventory is under 1,156 cu ft and you will not need access; choose the 10×30 storage unit above that, or if you want an aisle.
- +800 cu ft
- +$65–$130 / month
- $0.12 per cu ft
The difference at a glance
| Criterion | 10×20 storage unit | 10×30 storage unit |
|---|---|---|
| Dimensions | 10 ft × 20 ft | 10 ft × 30 ft |
| Floor area | 200 sq ft | 300 sq ft |
| Approximate volume | 1,600 cu ft | 2,400 cu ft |
| Usable volume | 1,360 cu ft | 2,040 cu ft |
| Medium boxes, alone | 453 | 680 |
| Typical home size | 3 bedroom house | 4–5 bedroom house |
| Vehicle storage | A full-size car or small boat, plus furniture | An RV or boat at facilities that allow it |
| Standard monthly cost | $160–$310 | $225–$440 |
| Climate-controlled cost | $195–$380 | $270–$530 |
| Best for | A whole three-bedroom house between closings, or long-term vehicle storage with room to spare. | A large house in full, a business holding stock, or an RV owner with a facility that allows it. |
Volumes assume an 8 ft ceiling and moderate packing density. Cost ranges are national references reviewed August 2026, not quotes.
What the extra space actually buys
Stepping from a 10×20 storage unit to a 10×30 storage unit adds 800 cubic feet of raw volume and 680 cubic feet of usable space. In physical terms that is roughly:
- 11 more queen bed sets, or
- 227 more medium boxes, or
- 14 more three-cushion sofas
The cost of that space is about $0.12 per cubic foot per month at the midpoint of the range — $65 to $130 more each month. Storage pricing is not linear, which is why sizing up is usually cheaper than people expect and renting two small units is usually dearer.
The practical threshold: a 10×30 storage unit brings 4 bedroom house into range, which a 10×20 storage unit cannot hold.
When to choose the 10×20 storage unit
- Your inventory comes in under 1,224 cu ft — that is the 90% line where a unit stops being comfortable.
- You will load it once and not return until you empty it.
- You are storing for three months or less, where the monthly saving still matters.
- A whole three-bedroom house between closings, or long-term vehicle storage with room to spare.
When to choose the 10×30 storage unit
- Your inventory is above 1,224 cu ft, or you are not sure — uncertainty is itself an argument for the larger unit.
- You need an access aisle. A 15% aisle drops a 10×20 storage unit to 1,156 cu ft, which is often the whole reason people outgrow it.
- You are storing for a year or more, where one repack costs more than the price difference.
- A large house in full, a business holding stock, or an RV owner with a facility that allows it.
The honest trade-off
The mistake is treating this as a price comparison. Over twelve months the difference is $780 to $1560. The cost of getting it wrong in the other direction is a second rental, a second move of everything you already carried once, and in the worst case a booking on a Saturday when the facility has nothing left in your size.
Against that, the argument for the smaller unit is real and often ignored: a unit you fill completely is cheaper per cubic foot, and an over-sized unit tends to fill with things you would otherwise have thrown away.
The deciding number is your own volume. Check the door width before storing a vehicle: an 8 ft door and a wide truck is a tight, mirror-folding manoeuvre. Also confirm the facility permits vehicles — many require proof of registration and insurance.
If you want to see the two loads rather than reason about them, the full item list for a 10×20 and what a 10×30 actually holds list worked inventories for each. The the five-step sizing method covers the method behind the 90% line used above, and the full price table by size shows where both sizes sit on the price curve.
Work out your own number
Related questions
Is a 10×30 storage unit worth the extra cost over a 10×20 storage unit?
It is if your inventory is above 1,224 cu ft, or if you need to walk into the unit. The extra 800 cu ft costs about $65–$130 more per month, which works out at roughly $0.12 per cubic foot.
How much bigger is a 10×30 storage unit than a 10×20 storage unit?
50% more volume: 2,400 cu ft against 1,600 cu ft, and 300 sq ft of floor against 200 sq ft.
Should I rent two 10×20 storage units instead of one 10×30 storage unit?
Rarely. Two 10×20 storage units cost $320–$620 against $225–$440 for the single larger unit, and you get two doors, two locks and two trips. The exception is when you need frequent access to one half and not the other.
Can I downsize from a 10×30 storage unit to a 10×20 storage unit later?
Yes — month-to-month leases are standard, and facilities will usually move you internally. Budget half a day for the transfer, and be realistic about whether you will actually purge 680 cu ft of belongings to make it fit.