🚗 Garage Storage Capacity Calculator
Estimate usable storage volume in your garage after accounting for vehicle parking space and walkways.
How the usable volume is worked out
The garage is treated as a box, then cut down to the share you can actually stack in:
total volume = length × width × usable height
usable storage = total volume × percentage usable / 100A 20 ft by 20 ft double garage with 8 ft of usable height is 3,200 cubic feet. At the default 30 percent that leaves 960 cubic feet of storage - about 265 twenty-seven gallon totes if they stacked with no gaps, which in practice means nearer 180 once you allow for aisles between stacks.
Picking the two numbers that matter
Usable height is not ceiling height. Measure to the lowest thing that crosses the space - the open garage door in its tracks, a light fitting, the joists of a storage loft - and stop there. Most garages lose one to two feet this way.
The percentage is where cars and walkways come off:
| Situation | Typical usable share |
|---|---|
| Two cars parked inside | 15-25% |
| One car, storage down one side and the back | 30-40% |
| No car, walkway only | 50-60% |
Even an empty garage never reaches 100 percent: you need a path to the back wall, clearance for the door to swing up, and space to lift a box down.
Frequently asked questions
How many cubic feet is a standard two-car garage?
About 3,200 at 20 ft × 20 ft × 8 ft of usable height. A single garage nearer 12 ft × 20 ft × 8 ft comes to about 1,920.
How much of a garage can I use for storage?
Around 30 percent with one car inside, and 15 to 25 percent with two. Parked vehicles plus the room to open their doors take most of the floor.
How many storage bins fit in 960 cubic feet?
Roughly 180 standard 27 gallon totes once aisles and imperfect stacking are allowed for. The theoretical maximum, at 3.6 cubic feet each, is about 265.