Overview

Amazon's aged inventory surcharges — formerly called long-term storage fees — are one of the most overlooked profit killers for FBA sellers. These escalating fees apply when products sit in Amazon's fulfillment centers beyond 365 days, and they can quietly erase margins on otherwise healthy products. With Amazon increasingly pushing sellers toward leaner inventory management, understanding and proactively managing inventory age has become a non-negotiable operational discipline.

What Are Aged Inventory Surcharges?

Aged inventory surcharges kick in when products remain in Amazon's fulfillment network for extended periods, typically past the one-year mark. Amazon uses these fees to discourage warehouse congestion caused by slow-moving stock and to keep fulfillment center capacity available for faster-selling inventory.

The surcharges are calculated on either a per-cubic-foot or per-unit basis, with Amazon applying whichever method produces the higher charge. This structure hits bulky, slow-selling items especially hard, since they consume disproportionate warehouse space while generating minimal throughput for Amazon's operations.

Key Factors That Drive Your Costs

• Inventory age — The core variable. Products approaching the 365-day mark should be flagged immediately, as surcharges ramp up significantly once that threshold is crossed.
• Size and weight — Oversized, heavy items occupy more cubic footage and rack up storage costs faster. A slow-moving oversized SKU can become a financial black hole.
• Q4 rate spikes — Standard monthly storage fees already jump during October through December. Carrying aged inventory into peak season compounds the damage with a double layer of elevated costs.
• Regular assessment cycles — Amazon evaluates inventory on a recurring schedule, flagging items that have exceeded age thresholds and applying surcharges automatically.

The Real Impact on Your Bottom Line

The financial damage from long-term storage fees often goes deeper than sellers realize. A product carrying a 20 percent margin that sits in Amazon's warehouse for 18 months can see that entire margin consumed by accumulated storage charges alone. What appeared profitable on a spreadsheet becomes a net loss once real storage costs are layered in.