Overview

Amazon charges monthly inventory storage fees to every FBA seller based on the space their products occupy in fulfillment centers. These fees are calculated using your daily average volume in cubic feet and vary by product size tier, time of year, and your storage utilization ratio. Understanding how these fees work is essential for managing FBA profitability and avoiding unnecessary costs that can quietly eat into margins.

Key Points / What Sellers Need to Know

• Fees are volume-based, not weight-based — Monthly storage fees are calculated on the daily average cubic footage your inventory occupies, measured by the dimensions of each unit when properly packaged and ready to ship per FBA requirements.
• Seasonal rates apply — Storage fees increase significantly during the October through December peak holiday season compared to the January through September off-peak period.
• Two fee components exist — The total storage charge is made up of a base monthly storage fee plus a potential utilization surcharge, which layers on top for sellers who meet certain thresholds.
• Product size tier matters — Standard-size and oversize items are assessed at different rates, with oversize products typically incurring higher per-cubic-foot charges.
• Dangerous goods carry different rates — Inventory classified as hazmat or dangerous goods is subject to separate, generally higher storage fee rates.
• Utilization surcharge targets excess inventory — Sellers with a high storage utilization ratio relative to their sales velocity may face an additional surcharge on top of base storage fees.

How Storage Fees Are Calculated

Amazon determines your monthly storage fee by taking the daily average volume of inventory you have stored in fulfillment centers throughout the month, measured in cubic feet. Each unit's volume is based on its dimensions when properly packaged according to FBA prep and shipping requirements — not the raw product dimensions. The per-cubic-foot rate applied depends on whether the product falls into the standard-size or oversize tier, and whether the current month is in the off-peak period (January through September) or the peak holiday season (October through December). Peak-season rates are substantially higher, often more than double the off-peak rate, reflecting increased demand for warehouse space during the holidays.