10×15 storage unit vs 10×20 storage unit
A 10×15 storage unit gives 150 square feet (sq ft) and about 1,200 cubic feet (cu ft); a 10×20 storage unit gives 200 sq ft and 1,600 cu ft. Choose the 10×15 storage unit if your inventory is under 867 cu ft and you will not need access; choose the 10×20 storage unit above that, or if you want an aisle.
- +400 cu ft
- +$35–$70 / month
- $0.13 per cu ft
The difference at a glance
| Criterion | 10×15 storage unit | 10×20 storage unit |
|---|---|---|
| Dimensions | 10 ft × 15 ft | 10 ft × 20 ft |
| Floor area | 150 sq ft | 200 sq ft |
| Approximate volume | 1,200 cu ft | 1,600 cu ft |
| Usable volume | 1,020 cu ft | 1,360 cu ft |
| Medium boxes, alone | 340 | 453 |
| Typical home size | 2 bedroom home | 3 bedroom house |
| Vehicle storage | A car plus household goods | A full-size car or small boat, plus furniture |
| Standard monthly cost | $125–$240 | $160–$310 |
| Climate-controlled cost | $155–$300 | $195–$380 |
| Best for | A two-bedroom house, a three-bedroom apartment, or a household that also wants a workshop corner. | A whole three-bedroom house between closings, or long-term vehicle storage with room to spare. |
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 10×15 storage unit to a 10×20 storage unit adds 400 cubic feet of raw volume and 340 cubic feet of usable space. In physical terms that is roughly:
- 6 more queen bed sets, or
- 113 more medium boxes, or
- 7 more three-cushion sofas
The cost of that space is about $0.13 per cubic foot per month at the midpoint of the range — $35 to $70 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 10×20 storage unit brings 3 bedroom house into range, which a 10×15 storage unit cannot hold.
When to choose the 10×15 storage unit
- Your inventory comes in under 918 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 two-bedroom house, a three-bedroom apartment, or a household that also wants a workshop corner.
When to choose the 10×20 storage unit
- Your inventory is above 918 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 10×15 storage unit to 867 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 whole three-bedroom house between closings, or long-term vehicle storage with room to spare.
The honest trade-off
The mistake is treating this as a price comparison. Over twelve months the difference is $420 to $840. 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. The jump from a 10x10 is 400 cubic feet — roughly a full bedroom set plus twenty boxes. If you are only 100 cubic feet over a 10x10, sell one piece of furniture instead of paying twelve months of a larger unit.
If you want to see the two loads rather than reason about them, what a 10×15 actually holds and what fits in a 10×20 list worked inventories for each. The work it out without a calculator covers the method behind the 90% line used above, and what each size costs per month shows where both sizes sit on the price curve.
Work out your own number
Related questions
Is a 10×20 storage unit worth the extra cost over a 10×15 storage unit?
It is if your inventory is above 918 cu ft, or if you need to walk into the unit. The extra 400 cu ft costs about $35–$70 more per month, which works out at roughly $0.13 per cubic foot.
How much bigger is a 10×20 storage unit than a 10×15 storage unit?
33% more volume: 1,600 cu ft against 1,200 cu ft, and 200 sq ft of floor against 150 sq ft.
Should I rent two 10×15 storage units instead of one 10×20 storage unit?
Rarely. Two 10×15 storage units cost $250–$480 against $160–$310 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 10×20 storage unit to a 10×15 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 340 cu ft of belongings to make it fit.