Amazon FBA Storage Fees Explained: How to Calculate and Cut Them
Storage fees are the quietest line on your FBA bill — until Q4 triples them. Here's exactly how they're calculated, how to estimate yours in one minute, and the levers that actually reduce them.
How Amazon Actually Charges for Storage
FBA monthly storage fees are charged per cubic foot of space your inventory occupies, measured from your product's packaged dimensions. Two things drive the bill: how much volume you store, and when you store it — the October–December rate is roughly three times the January–September rate for standard-size items.
The division by 1728 converts cubic inches to cubic feet (12 × 12 × 12). Rates differ by size tier (standard vs oversize) and change over time — always verify the current rate in Seller Central before planning.
The Three Fees Sellers Confuse
| Fee | When it applies | What drives it |
|---|---|---|
| Monthly storage | Every month, all inventory | Volume × seasonal rate |
| Aged inventory surcharge | Units stored 181+ days | Age of each unit |
| Storage utilization surcharge | High stock-to-sales ratios | How slowly you sell vs store |
The monthly fee is unavoidable — it's the cost of using FBA. The other two are penalties for overstocking, and they're the ones you can engineer away.
Five Levers That Actually Cut Storage Cost
A product that's profitable at the January–September storage rate can flip to a loss in Q4 if it sells slowly. Run the numbers at both rates before committing to a large autumn shipment.
Estimate Yours in One Minute
Grab your packaged dimensions from your listing or supplier spec sheet, count your units in storage, check the current rate in Seller Central, and put the three numbers into the free calculator. No account needed — and if you want this monitored automatically from your live inventory, the Inventory & Restock tools do it continuously.