📊 How Amazon Calculates Your IPI Score (and How to Raise It)

Your Inventory Performance Index (IPI) score is Amazon's way of grading how efficiently you manage your FBA inventory. A low score can trigger storage limits that cap how much product you can send into Amazon's fulfillment centers — directly threatening your ability to stay in stock and compete.

This article breaks down exactly how Amazon calculates your IPI score, what each component means in practice, and the specific actions you can take to raise your score and keep your FBA operations running without restriction.

A score between 0 and 1,000 that Amazon assigns to FBA sellers. It measures how well you balance having enough stock to sell without overstocking products that sit idle. Amazon reviews your score weekly, and sellers who fall below the threshold (currently 400) are subject to storage volume limits.

When your IPI drops below Amazon's minimum, Amazon caps the total cubic feet of inventory you can store across their fulfillment network. This can prevent you from restocking best-sellers during peak periods — a serious operational risk.

Units that Amazon projects will take more than 90 days to sell based on your current sales velocity. Excess inventory drives up storage fees and negatively impacts your IPI score.

FBA units that are physically in Amazon's fulfillment centers but are not attached to an active, buyable listing. Stranded inventory costs you storage fees while generating zero revenue.

The ratio of units sold and shipped over the past 90 days compared to your average units on hand during that same period. A higher sell-through rate signals healthy inventory management to Amazon.

The percentage of time your replenishable ASINs have been in stock over the past 30 days, weighted by the sales of each ASIN. Running out of stock on high-velocity items hurts this metric.

Each step below targets a specific driver of your IPI score. Work through them in order — the early steps typically have the fastest impact.

Before making changes, understand where you stand and what's dragging your score down.

💡 Pro Tip: Amazon updates your IPI score weekly (every Monday). After making inventory changes, allow at least one full week before evaluating the impact on your score.

Stranded inventory is the highest-priority fix because it costs you money without generating any sales. It also has an outsized negative effect on your score relative to the effort required to fix it.

💡 Pro Tip: Set a weekly calendar reminder to check your stranded inventory report. Listings can become stranded silently (e.g., after a policy update) and will cost you fees every day they go unresolved.

Excess inventory is any stock Amazon projects will take longer than 90 days to sell. Reducing it improves your IPI score and lowers your storage fees at the same time.

💡 Pro Tip: When calculating whether to discount or remove inventory, factor in long-term storage fees (charged on units stored more than 365 days) and the upcoming storage fee surcharge periods (typically October–December). Paying to remove inventory is often cheaper than storing it through peak fee months.

Your sell-through rate reflects how quickly inventory moves relative to what you have on hand. A low rate usually means you're over-sending inventory for your current sales velocity.

💡 Pro Tip: Amazon weights sell-through rate by your highest-volume ASINs. Improving the sell-through rate on your top 5–10 SKUs will have a significantly greater impact on your IPI than improving it across dozens of low-volume products.

While reducing excess inventory, be careful not to go out of stock on your best-selling products. Your in-stock rate is weighted by revenue — running out of a top seller can drop your score significantly.

💡 Pro Tip: If your IPI is close to the threshold and you're worried about storage limits, prioritize in-stock rate for your top sellers over everything else. A stockout on a high-revenue ASIN can cause an immediate and steep score drop.

Sending too much inventory at once is one of the most common IPI mistakes. Amazon rewards sellers who send smaller, more frequent shipments calibrated to actual demand.

💡 Pro Tip: If you source from overseas and need to hold more inventory due to long lead times, consider splitting storage between FBA and a 3PL (third-party logistics provider). Keep only 60–90 days of stock at Amazon and replenish from your 3PL as needed. This protects your IPI while maintaining supply chain security.

IPI management is not a one-time fix — it requires ongoing attention, especially as your catalog grows.

Seller: A beginner seller with 12 months of FBA experience, selling home goods across 25 ASINs.

Problem: In September, their IPI score dropped to 390 — just below Amazon's 400 threshold. Amazon notified them that storage limits would apply starting the following quarter, potentially preventing them from sending Q4 inventory.

Action taken:

Result: IPI score rose to 430 within two weekly update cycles. Storage limits were not applied, and the seller was able to send full Q4 replenishment shipments without restriction.

Seller: An established private label seller doing $1.2M annually with 80+ active FBA ASINs.

Problem: After aggressively expanding their catalog, their IPI dropped from 620 to 510 over three months. Excess inventory from new product launches that underperformed was the primary cause.

Action taken:

Result: IPI recovered to 590 within 6 weeks and stabilized above 600 for the following quarter. Long-term storage fees dropped by 40% compared to the prior quarter.

Many sellers send 6–12 months of inventory to FBA because the per-unit shipping cost is lower in bulk. But if a product underperforms, that decision creates excess inventory that tanks your IPI score and triggers long-term storage fees.

What to do instead: Send 60–90 days of inventory based on actual recent sales velocity, not projected potential. Prove demand first, then scale your replenishment quantities.

Stranded inventory is easy to ignore because it doesn't appear in your main active listings view. Sellers often don't notice it until they receive a storage fee charge for products generating zero revenue.

What to do instead: Make stranded inventory review a fixed part of your weekly workflow. It takes 10–15 minutes and prevents compounding losses.

Sellers under pressure to raise their IPI sometimes reduce inventory across all ASINs without distinguishing between slow-movers and top-sellers. This can cause stockouts on high-revenue products, which simultaneously hurts the in-stock rate component of the IPI and costs significant sales.

What to do instead: Target excess inventory reduction at your slowest-moving ASINs only. Protect stock levels on your top sellers aggressively.

Amazon sends early warning notifications when your IPI is trending toward the threshold. Many sellers dismiss these as routine emails and don't act until limits are actually in place — at which point it may be too late to send Q4 inventory.

What to do instead: Treat any IPI warning notification as an immediate operational priority. Score improvements take one to three weeks to register, so early action is critical.

After consistently applying the steps in this guide, sellers typically experience:

Amazon's current minimum IPI threshold is 400. Sellers who fall below this score are subject to storage volume limits on their FBA inventory. Amazon evaluates your score at specific review periods throughout the year, so the timing of when limits are applied depends on where your score stands during those evaluation windows. Check your Seller Central dashboard for your current score and any active notifications.

Amazon recalculates and updates IPI scores weekly, typically on Mondays. Changes you make to your inventory — such as fixing stranded listings, removing excess stock, or improving sell-through — will generally reflect in your score within one to three weekly update cycles.

Not directly. Your IPI score does not appear to be a direct input into Amazon's search ranking algorithm. However, the behaviors that improve your IPI — staying in stock, maintaining healthy sell-through rates, and keeping listings active — do positively influence your sales velocity and conversion rate, which are known factors in search visibility.

Yes. IPI is based on relative inventory efficiency, not the size of your catalog. Sellers with hundreds of ASINs can maintain excellent scores as long as each product is appropriately stocked relative to its sales velocity, no stranded inventory exists, and there is minimal excess inventory across the catalog. The key is implementing systematic monitoring at scale.

Start with stranded inventory — it has the fastest and most direct impact because every stranded unit is deadweight with no offsetting sales contribution. After stranded inventory is cleared, shift focus to your highest-excess ASINs and take immediate action to accelerate sell-through or submit removal orders. Improving these two areas simultaneously typically produces the fastest score recovery.