Amazon IPI Score: How to Improve Your Inventory Performance Index and Avoid Storage Limits

Amazon's Inventory Performance Index (IPI) is a 0–1,000 score (displayed as a number between 0 and 1,000) that measures how efficiently you use FBA storage. The minimum IPI threshold is 400. Sellers below 400 have their FBA storage capacity reduced — sometimes dramatically.

Storage limit enforcement: Amazon reviews IPI scores on a quarterly basis (at the end of each quarter). Sellers below the threshold receive storage volume limits that cap how many units they can store in FBA. These limits are category-specific and can prevent you from sending inventory during peak Q4.

Sellers above 450 typically receive unlimited or very high storage limits. The IPI score is not just a compliance metric — it is a competitive advantage. High-IPI sellers can hold deep Q4 inventory while low-IPI sellers get cut off.

Check your IPI score in Seller Central under Inventory > Inventory Performance.

1. Excess Inventory Percentage: the share of your FBA units that Amazon classifies as "excess" (more than 90 days of supply based on recent sales velocity). Excess inventory earns you a low score on this metric and also triggers aged inventory surcharges. Fix: create removal orders or run promotions to sell down excess stock.

2. Stranded Inventory Percentage: units sitting in FBA with no active listing (the listing was suppressed, deleted, or has no buyable offer). These units incur storage fees but generate no sales. Fix: audit the Stranded Inventory page weekly and either relist, create a removal order, or merge with the active listing.

3. FBA In-Stock Rate: the percentage of your replenishable ASINs (those that had sales in the last 60 days) that are currently in stock. Stockouts lower this metric. Fix: tighten your reorder point calculations and send replenishment shipments before you hit zero.

4. Sell-Through Rate: units sold in the last 90 days divided by average units in FBA over the same period. A higher sell-through means your inventory is moving efficiently. Fix: eliminate slow sellers through promotions, price cuts, or removal; concentrate FBA on your fastest-moving SKUs.

Stranded inventory is the highest-impact quick fix for most sellers. Go to Seller Central > Inventory > Fix Stranded Inventory. Common stranding reasons: listing closed by Amazon (price violation, quality issue), listing deleted by seller accidentally, ASIN merged with a different parent, or listing suppressed for missing attributes.

For each stranded unit: if the root cause is a fixable listing issue (missing attribute, price concern), fix the listing. If the unit is discontinued or damaged, create a removal order. Do not leave stranded units sitting — they consume storage capacity and depress your IPI with every passing day.

Automation tip: set a weekly calendar reminder to review the Stranded Inventory page. It takes 5–10 minutes to clear new strandings as they appear. Left unchecked for a month, stranded inventory compounds quickly during high-volume periods.

Amazon flags inventory as excess when you have more than 90 days of supply on hand at current sales velocity. This is a forecast-based calculation — if your velocity is low, even modest stock levels can trigger the excess flag.

Options for excess inventory: (1) Run a sale or coupon to increase sell-through rate. (2) Create a removal order and redistribute units to a 3PL for alternative channel fulfillment. (3) Use Amazon's Outlet Deals program to offer a percentage-off deal to bargain shoppers. (4) Liquidate through Amazon's Liquidation Program at 5–15% of average selling price.

Proactive reorder planning: use Amazon's Restock Report (under Inventory > Restock Inventory) to set reorder points based on your lead times and sales velocity. This prevents both stockouts (which hurt in-stock rate) and overordering (which creates excess).

IPI scores update weekly. Actions you take today (fixing stranded inventory, creating removal orders for excess) will reflect in your IPI within 1–2 weeks.

Realistic improvement timeline: from 300 to 400 (if you are below threshold): 4–8 weeks of focused cleanup. From 400 to 500: 2–3 months of consistent inventory discipline. From 500 to 600+: 6+ months, requires tightly managed reorder cycles and minimal excess.

Seasonal management: IPI assessments that happen at quarter-end can catch you with high Q4 inventory. Plan to build up FBA stock for Q4 only after confirming your IPI is above 450 — giving yourself headroom for the inevitable increase in storage that comes with holiday inventory.

Key principle: IPI rewards sellers who treat FBA as a flow-through channel (inventory in, sold out, replenished) rather than a warehouse. The higher your inventory turns, the higher your IPI — and the lower your storage costs per unit.