What are FBA storage limits and how does Amazon set them?
Storage limits control how much inventory Amazon lets you keep in its fulfillment centers. Amazon uses a capacity management system that allocates storage space to sellers based on three primary factors: your IPI score (higher scores get more capacity), your historical and forecasted sales volume (faster sellers get more space), and overall warehouse availability (Amazon tightens limits when FCs are near capacity, especially in Q4).
Storage limits are measured in cubic feet, not units. A seller might have a 5,000 cubic foot limit for standard-size items and a 2,000 cubic foot limit for oversize items. The limits update roughly every quarter, with Amazon providing 6 to 8 weeks of advance notice before changes take effect. Sellers with IPI scores below 400 (as of 2026) face reduced capacity and may have restock limits imposed on top of storage limits.
The capacity system replaced the older ASIN-level restock limits in 2023. Under the current system, you can allocate your total capacity across ASINs however you choose, giving sellers more flexibility to prioritize products with strong sell-through rates. However, total capacity is still constrained, and exceeding your limit results in overage fees of $10 per cubic foot per month.
Storage limit math: capacity utilization
(On-hand cubic feet + Inbound cubic feet) / Storage limit
Overage fee =
$10 per cubic foot per month for usage above your limit
Example:
Storage limit: 4,200 cu ft
On-hand: 3,600 cu ft
Inbound shipments: 900 cu ft
Total: 4,500 cu ft (107% utilization)
Overage: 300 cu ft x $10 = $3,000/month
Example: capacity planning for a $3.5M seller
A seller doing $3.5M with 45 ASINs has a standard-size storage limit of 6,800 cubic feet and an oversize limit of 2,200 cubic feet. Current on-hand: 5,900 cu ft standard + 1,850 cu ft oversize. Inbound shipments in transit: 1,400 cu ft standard + 500 cu ft oversize. Total projected: 7,300 cu ft standard (107.4% of limit) and 2,350 cu ft oversize (106.8% of limit).
Both storage types are over capacity. The overage fees would be: standard (500 cu ft x $10 = $5,000/month) + oversize (150 cu ft x $10 = $1,500/month) = $6,500/month in penalties. To avoid this, the seller has several options: (1) create removal orders for slow-moving ASINs to free up 650+ cubic feet, (2) shift 3 to 4 oversized ASINs to MFN temporarily, (3) route future inbound shipments through AWD so Amazon drip-feeds inventory to FBA within capacity.
The most effective long-term fix is raising IPI above 400 (this seller is at 380), which increases the storage allocation in the next quarterly update. Removing 300 units of aged inventory and fixing two suppressed listings would likely push IPI to 420+, unlocking an estimated 1,200 additional cubic feet of capacity.
Common mistakes
- Forgetting that inbound shipments count toward your capacity. Your storage utilization = on-hand + inbound. A shipment of 2,000 units in transit pushes you over the limit even if your warehouse count looks fine. Always check inbound volume before creating new shipments.
- Spreading capacity evenly across ASINs instead of prioritizing by velocity. Under the capacity system, you choose how to allocate space. Giving 200 cubic feet to a SKU that sells 2 units/day when another SKU selling 30 units/day needs that space is a $15,000/month mistake in lost revenue.
- Ignoring the quarterly capacity update timeline. Amazon announces limit changes 6 to 8 weeks in advance. If your IPI is near 400, those weeks are your window to improve it through removal orders, sell-through campaigns, and fixing stranded or suppressed inventory. After the deadline, you are locked into the lower allocation for the full quarter.