About the Storage Unit Size Calculator
This storage unit size calculator works out how much space your belongings need and which standard self-storage unit will hold them. Count your furniture, appliances and boxes, set how high you are willing to stack, and it returns the total volume, the floor area required and the smallest unit — from a 5 × 5 locker to a 10 × 30 garage-size unit — that fits.
Use it when you are moving between homes, renovating, downsizing or storing a student’s things over the summer. Renting one size too big can add hundreds of dollars a year, while a unit that is too small means paying for a second one or a cramped, unsafe stack.
Item volumes are typical moving-industry estimates. The packing-efficiency setting leaves room for a walkway and the gaps around odd-shaped furniture; most units have ceilings around 8 ft, but stacking above 6–7 ft is awkward and risky for anything heavy.
How to use the storage unit size calculator
- 1Count the furniture and appliances you plan to store.
- 2Estimate the number of medium boxes and add any odd items as extra cubic feet.
- 3Set how high you can safely stack — 6–7 ft is typical.
- 4Lower the packing efficiency if you need a walkway to reach things often.
- 5Rent the recommended unit, or go one size up if usable space is over 90% full.
Formula and method
Each item type has a typical packed volume, such as 50 cu ft for a three-seat sofa or 3 cu ft for a medium box. Multiplying by your quantities and adding extras gives the total cubic feet to store.
A storage unit is sold by floor area, so the volume is divided by how high you will stack and by a packing efficiency that leaves room for a walkway and gaps. With a 7 ft stack and 75% efficiency, every square foot of floor holds about 5.25 cu ft. The calculator then picks the smallest standard unit (5×5, 5×10, 10×10, 10×15, 10×20, 10×25 or 10×30 ft) with at least that floor area.
- V
- Total volume of your belongings (cu ft)
- stack height
- How high you will stack items (ft)
- efficiency
- Share of the space you can fill (e.g. 75%)
Worked examples
One-bedroom apartment (default inventory)
The furniture and 25 boxes plus 20 cu ft of extras total 390 cu ft. Stacked 7 ft high at 75% efficiency, each square foot holds 5.25 cu ft, so you need about 74 sq ft of floor — a 10 × 10 unit with 525 cu ft of usable space.
Student summer storage
A twin bed (40), a dresser (35), 20 boxes (60) and 10 cu ft of extras make 145 cu ft. That needs about 27.6 sq ft of floor, just over a 5 × 5 unit, so a 5 × 10 unit is the right size.
Three-bedroom house stacked 8 ft high
This household totals 965 cu ft. Stacking to 8 ft at 75% efficiency gives 6 cu ft per square foot, so you need about 161 sq ft — more than a 10 × 15 — making a 10 × 20 unit (1,200 cu ft usable) the fit.
Frequently asked questions
What fits in a 10x10 storage unit?+
A 10 × 10 unit (100 sq ft, about 800 cu ft to the ceiling) typically holds the contents of a one-bedroom apartment: a sofa, bed, dresser, dining set, a TV stand and 20–30 boxes.
What size storage unit do I need for a 2-bedroom apartment?+
Most two-bedroom apartments fit in a 10 × 15 unit. If you have large appliances, many boxes or bulky sectionals, a 10 × 20 gives room to keep a walkway.
How tall are storage units?+
Most self-storage units have ceilings around 8 ft, with some drive-up units up to 10 ft. Stacking heavy items above head height is unsafe, so plan on 6–7 ft of usable height.
How much does a 5x10 storage unit hold?+
A 5 × 10 unit has 50 sq ft of floor, enough for a mattress set, a dresser and 15–25 boxes — about a dorm room or small studio’s worth of belongings.
Should I leave an aisle in my storage unit?+
If you will need to get items out before you move them all, leave a walkway down the middle. That costs about 20–30% of the space, which the packing-efficiency setting accounts for.