Overview

Amazon has changed the way it calculates FBA capacity limits, moving from a six-month to a five-month projected sales window when determining how much warehouse space each seller receives. The adjustment has resulted in reduced allocations across the board — even for sellers with strong Inventory Performance Index scores — and signals a broader push by Amazon to manage fulfillment network congestion more aggressively.

What's Changing

• Shorter sales projection window — Capacity allocations are now based on five months of expected sales instead of six, which mathematically reduces the storage space most sellers are granted.
• Monthly recalculation cycle — Amazon continues to update capacity figures during the fourth week of each month, so sellers should check their dashboards after each cycle.
• IPI threshold unchanged at 400 — The minimum score needed to avoid automatic storage restrictions remains at 400.
• High IPI scores no longer guarantee protection — Sellers with scores above 550 have reported significant capacity cuts, indicating Amazon is weighting network-wide factors more heavily than individual performance.

How the New Capacity Formula Works

Amazon now calculates FBA storage allocations using a blend of inputs: five months of projected sales, your current IPI score, historical sales data, and the available warehouse space across Amazon's fulfillment network at the time of recalculation. Because the formula incorporates systemwide constraints, a seller can do everything right on an individual level and still see their allocation shrink if Amazon's warehouses are running near capacity in their region or product category.

This means sellers should treat their capacity allocation as a multi-variable equation rather than something they can optimize by focusing on a single metric. Strong IPI scores help, but they no longer function as an insurance policy against cuts.

Why Strong IPI Scores Are No Longer a Safety Net

For years, maintaining an IPI score above 500 was considered sufficient to avoid meaningful storage restrictions. The 2025 changes have disrupted that assumption. Multiple sellers with scores of 550 or higher have seen their capacity reduced under the new model, which suggests Amazon is placing greater emphasis on aggregate demand and warehouse utilization rates.