Amazon IPI Score: The Four Factors and What It Gates

The Amazon IPI score is a single number between 0 and 1,000 that rates how efficiently you run your FBA inventory. It refreshes weekly and it looks back about 90 days, so what you see today is mostly the consequence of decisions you took two months ago. Amazon publishes the four things that move it and does not publish the weights, which is why two sellers with identical dashboards can sit 80 points apart.

Here is what the score is made of, what it still controls, and how to read yours without guessing.

What the Amazon IPI score measures

Amazon's inventory performance guidance, posted on August 13, 2026, and the original IPI announcement name four inputs:

• Excess inventory. A unit counts as excess once you hold more than 90 days of supply against forecast demand. Amazon's own recommendation in the 2026 post is to carry 30 to 60 days of expected sales.
• FBA sell-through rate. Defined as units shipped over the past 90 days divided by the average units on hand during that period. It is a ratio, not a percentage.
• Stranded inventory. Units sitting in a fulfillment center with no active listing attached. They pay storage and sell nothing.
• In-stock rate on popular items. How often your best-selling replenishable ASINs are actually buyable.

Amazon does not publish how the four are weighted. Treat the score as a thermometer, not as a formula you can solve.

A worked example, end to end

Two sellers ship the same volume. Over 90 days each one ships 1,350 units.

Seller A holds an average of 450 units on hand.

• Sell-through: 1,350 divided by 450 = 3.0
• Daily run rate: 1,350 divided by 90 = 15 units a day
• Days of supply: 450 divided by 15 = 30 days

Thirty days is inside Amazon's recommended 30 to 60 band, and well under the 90-day excess line. Nothing in the excess bucket.

Seller B holds an average of 1,800 units on hand.

• Sell-through: 1,350 divided by 1,800 = 0.75
• Days of supply: 1,800 divided by 15 = 120 days

Same sales, four times the stock. Seller B is 30 days of supply past the 90-day line, so a slice of that inventory lands in the excess bucket, drags sell-through down, and will start paying aged inventory surcharges as the days accumulate. The sales column is identical. Only the denominator changed.

That is the whole lesson of the score: it is a ratio, so you can raise it by selling more or by holding less, and holding less is the lever you control this week.

How many days of supply are you holding?

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What the IPI score still gates, and what it does not

This is where most of the advice on the internet is out of date.

The IPI score used to drive a quarterly storage limit, with a published cut-off. Amazon raised that threshold to 400 effective January 1, 2020, with two evaluation weeks per quarter and six weeks in between to recover: if you were below on the first check you were warned, and if you were still below on the second the limit applied for the next quarter. Sellers above the line were told they had unlimited storage for standard-size and oversize items.

That mechanism no longer exists. In March 2023 Amazon replaced the weekly restock limit and the quarterly storage limit with a single monthly capacity limit per storage type, measured in cubic feet, and introduced Capacity Manager, which lets you request more capacity against a reservation fee that you specify.

So the practical answer in 2026: your IPI score is one of the inputs into your monthly FBA capacity limit, alongside your sales volume and the capacity Amazon has available. There is no published score that buys you unlimited storage any more. A high score widens the limit; a low score narrows it. Our breakdown of how your monthly FBA capacity limit is actually set walks through the rest of the inputs.

Where to read yours

The Inventory Performance dashboard in Seller Central shows the score and the four factors underneath it, each with the ASINs dragging it down. Two of them are fixable without touching a price:

• Stranded inventory is a listing problem, not an inventory problem. It is the fastest points you will ever recover, and why FBA inventory goes stranded and how to clear it covers the usual causes.
• Excess inventory is a removal or markdown decision, and in Q4 it is also a storage decision: what FBA storage costs per cubic foot in Q4 is the number that makes the case for ordering removals in September rather than November.

For the full picture of every clock running against your FBA stock at once, start from our pillar on Amazon FBA inventory management.

What to actually do with the number

1. Read the denominator, not the score. Days of supply per ASIN tells you more than the headline number, and it updates faster in your own data than in the dashboard.
2. Clear stranded units first. Zero effort on demand, immediate effect on three of the four factors.
3. Cut the tail, not the winners. Excess sits in slow ASINs. Removing 200 units of a 180-day-of-supply SKU moves the score further than anything you can do to a bestseller.
4. Do it before the capacity month you need. The score looks back 90 days, so a correction made in October shows up in the limit you get for December, not November.

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