Amazon FBA Storage Fee Calculator
Estimate your monthly Amazon FBA storage fees from item size, units in stock and season — with the per-unit cost.
How it works
cubic feet per unit = (length × width × height) ÷ 1728 · total cu ft = per-unit × units · monthly fee = total cu ft × rate · storage fee = monthly fee × months
Amazon charges FBA monthly storage by the volume your inventory occupies, not its weight. Convert each item’s dimensions to cubic feet (divide cubic inches by 1728), multiply by units in stock to get total volume, then multiply by the per-cubic-foot rate for your size tier and time of year. Rates jump sharply in the Oct–Dec peak — standard-size roughly triples — which is why overstocking slow sellers before the holidays is expensive. Oversize items use a lower per-cubic-foot rate because they’re bulky by design. The rates here are approximate US figures and Amazon revises them, so confirm the current schedule.
Worked example
A 10 × 8 × 4 in item is (10 × 8 × 4) ÷ 1728 = 0.1852 cu ft. With 500 units that’s 92.59 cu ft. At the standard Jan–Sep rate of $0.87/cu ft, monthly storage is 92.59 × 0.87 = $80.55, or about $241.66 over three months — roughly $0.48 per unit.
Frequently asked questions
Why are Q4 storage fees so much higher?
Warehouse space is scarcest in the run-up to the holidays, so Amazon raises monthly storage rates for October through December — standard-size roughly triples versus the rest of the year. Send in only what you expect to sell through the quarter to avoid paying peak rates on stock that lingers.
Is this the same as the long-term storage fee?
No. This is the ongoing monthly storage fee based on volume. Amazon also charges a separate aged-inventory (long-term) surcharge on units that have sat in fulfillment centers beyond a set number of months. Slow-moving stock can attract both, so watch your sell-through.
How do I lower my FBA storage costs?
Keep less idle inventory, improve sell-through so units don’t age, and reduce packed dimensions where you can — fees scale directly with cubic feet. Removing or liquidating dead stock before the Q4 peak often saves more than any packaging tweak.
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Storage-fee rates are approximate US Amazon figures and change over time (and by year) — check the current Seller Central fee schedule for your marketplace.