Amazon FBA Inventory Limits Explained: How to Manage Restock Limits

What Are FBA Inventory Limits?

Amazon FBA inventory limits cap how much product you can store in Amazon's fulfillment centers. These limits exist because warehouse space is finite and Amazon prioritizes products that sell quickly.

The core principle: Amazon wants inventory that moves, not inventory that sits.

Types of FBA Limits

Restock Limits

The maximum inventory you can have on-hand and inbound combined:

Restock Limit = Maximum (On-Hand + Inbound)

Checked per storage type:

• Standard-size
• Oversize
• Apparel
• Footwear
• Aerosol/flammable

ASIN-Level Limits

Some products have individual limits based on:

• Sales history for that ASIN
• Category restrictions
• Hazmat classification

Account-Level Limits

Your overall FBA capacity across all ASINs.

The IPI Score: Your Key Metric

IPI (Inventory Performance Index) determines your limits.

What Affects IPI

Factor	Weight	How to Improve
Sell-through rate	High	Increase sales, reduce excess
Excess inventory	High	Remove or liquidate slow movers
Stranded inventory	Medium	Fix listing issues promptly
In-stock rate	Medium	Avoid stockouts on top sellers

IPI Score Ranges

Score	Assessment	Limit Impact
550+	Excellent	Maximum limits
450-549	Good	Standard limits
350-449	Needs improvement	Reduced limits
Below 350	Poor	Severe restrictions

Checking Your IPI

In Seller Central:

1. Go to Inventory → Inventory Planning
2. Click "Inventory Performance"
3. View current IPI and breakdown

How Limits Are Calculated

Amazon's formula (simplified):

Your Limit = Base Allocation × IPI Multiplier × Seasonal Factor × Category Factor

Factors That Increase Limits

• Higher IPI score
• Strong sales velocity
• Good sell-through history
• Peak season capacity expansion

Factors That Decrease Limits

• Low IPI score
• Aged inventory (90+ days)
• Stranded ASINs
• Q4 capacity constraints (everyone wants space)

Strategies to Maximize Your Limits

Strategy 1: Improve Sell-Through Rate

Sell-through = Units sold / Units available

Actions:

• Price competitively
• Run promotions on slow movers
• Improve listings (photos, bullets, A+ content)
• Adjust PPC spend

Strategy 2: Eliminate Excess Inventory

Excess inventory destroys IPI. Amazon defines excess as:

• More than 90 days of supply
• Not selling at current rate

Options:

• Create removal orders
• Run Lightning Deals
• Lower prices aggressively
• Use Amazon Outlet

Strategy 3: Fix Stranded Inventory

Stranded = inventory in FBA but not sellable (listing issues)

Check Inventory → Fix stranded inventory weekly. Common causes:

• Listing deleted/suppressed
• ASIN merges
• Category approval lost

Strategy 4: Maintain In-Stock on Top Sellers

Stockouts hurt IPI because Amazon factors in-stock rate. For your A items:

• Set aggressive reorder points
• Use FBA inventory planning alerts
• Have backup FBM listings

Strategy 5: Right-Size Shipments

Don't send 6 months of inventory "just in case." Send:

• Fast movers: 4-6 weeks supply
• Medium movers: 6-8 weeks supply
• Slow movers: Consider FBM instead

Managing Q4 Limit Constraints

Q4 is brutal for FBA limits. Everyone wants warehouse space.

Pre-Q4 Actions (August-September)

1. Clear aged inventory before Q4
2. Send Q4 stock early (September)
3. Maximize IPI score going into Q4
4. Plan FBM backup for overflow

During Q4

• Monitor limits weekly
• Prioritize top sellers for limited space
• Use FBM for slow movers
• Consider 3PL for overflow

Post-Q4

Limits often expand in January. Catch up on inventory you couldn't send.

FBA Limit Workarounds

Legitimate Workarounds

Workaround	How It Helps
FBM backup	Sell without FBA limits
3PL storage	Hold inventory until FBA opens
Multi-channel fulfillment	FBA ships for non-Amazon orders
Amazon Warehousing & Distribution	Separate upstream storage

Things That Don't Work

• Creating multiple seller accounts (against TOS)
• Gaming inventory counts (Amazon detects this)
• Sending slightly over limits (rejected or fees)

Reading Your Restock Limit Dashboard

In Seller Central → Inventory → Inventory Planning → Restock Limits

Key metrics:

• Maximum shipment quantity: How much you CAN send
• On-hand: Current FBA inventory
• Inbound: Inventory in transit/receiving
• Available: Room for new shipments

Available = Maximum - On-hand - Inbound

Multi-Channel Limit Strategy

For Shopify + Amazon sellers:

Unified View Needed

Know your total position:

• FBA available
• FBA inbound
• Warehouse available
• What can ship to FBA vs. must stay

Allocation Decisions

When FBA limits are tight:

1. Prioritize Amazon bestsellers for FBA
2. Fulfill Shopify from warehouse
3. Use FBM for Amazon overflow

ReplenishRadar shows unified inventory and helps allocate between channels based on demand forecasts and FBA constraints.

Monitoring and Alerts

Track weekly:

• Current IPI score
• Available capacity by storage type
• Aged inventory percentage
• Stranded inventory count

Set alerts for:

• IPI dropping below 450
• Available capacity below 2 weeks of shipments
• Stranded inventory appearing

Get FBA-aware inventory planning. Start a free trial and see transfer recommendations that account for your limits.

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Related Reading:

• Amazon FBA Restock Strategies
• Fix FBA Stranded Inventory
• Q4 Inventory Planning Checklist