Storage unit size comparison tool
This tool puts any two storage unit sizes side by side, drawn to scale, and reports the difference in floor area, gross volume, usable capacity and monthly cost. It also shows what the extra space is worth in furniture terms — bed sets, sofas or boxes.
- 8 sizes, any pairing
- Drawn to scale
- Cost per cubic foot
The full size ladder
| Size | Floor area | Volume | Usable | Step up adds | Extra cost |
|---|---|---|---|---|---|
| 5×5 | 25 sq ft | 200 cu ft | 170 cu ft | — | — |
| 5×10 | 50 sq ft | 400 cu ft | 340 cu ft | +200 cu ft | +$15–$35 |
| 5×15 | 75 sq ft | 600 cu ft | 510 cu ft | +200 cu ft | +$20–$30 |
| 10×10 | 100 sq ft | 800 cu ft | 680 cu ft | +200 cu ft | +$15–$40 |
| 10×15 | 150 sq ft | 1,200 cu ft | 1,020 cu ft | +400 cu ft | +$35–$60 |
| 10×20 | 200 sq ft | 1,600 cu ft | 1,360 cu ft | +400 cu ft | +$35–$70 |
| 10×25 | 250 sq ft | 2,000 cu ft | 1,700 cu ft | +400 cu ft | +$35–$60 |
| 10×30 | 300 sq ft | 2,400 cu ft | 2,040 cu ft | +400 cu ft | +$30–$70 |
Usable volume assumes moderate packing density and no access aisle.
Written comparisons
The pairings people search for most, each with the threshold where the answer flips:
- 5×5 storage unit vs 5×10 storage unit — $40–$75 against $55–$110
- 5×10 storage unit vs 10×10 storage unit — $55–$110 against $90–$180
- 10×10 storage unit vs 10×15 storage unit — $90–$180 against $125–$240
- 10×15 storage unit vs 10×20 storage unit — $125–$240 against $160–$310
- 10×20 storage unit vs 10×30 storage unit — $160–$310 against $225–$440
How to use a comparison
Comparing on headline price alone gets the decision wrong, because storage pricing is not linear — larger units are consistently cheaper per cubic foot. The useful comparison is cost per cubic foot against how much space you actually need.
Work out your own volume first with the size calculator, then come back here. A comparison without your own number is entertainment, not a decision.
Assumptions and limitations
Floor area and gross volume come directly from nominal unit dimensions with an assumed 8 ft ceiling. Usable capacity changes with the selected packing density and the displayed cost is a dated national reference range, not a quote. The comparison does not account for a specific facility's door, corridor, columns, ceiling obstructions or promotions.
Related questions
Is a 10x10 twice as big as a 5x10?
Yes, exactly — 100 sq ft against 50 sq ft, and 800 cu ft against 400 cu ft. The cost difference is well under double, which is the general pattern in storage pricing. Full comparison.
Which storage unit size gives the best value?
The 10x15 and 10x20 typically have the lowest cost per cubic foot. The 5x5 has the highest — needing two of them is a clear signal to move up a size.
How much more does the next size up cost?
Between $15 and $130 per month depending on where you are on the ladder, for 200 to 400 extra cubic feet. The table above shows every step.