Amazon IPI Score: What It Is and Why It Governs Capacity | Inventory Hero
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Amazon IPI Score: What It Is and Why It Governs Capacity
The Amazon IPI score is a 0 to 1000 inventory health rating from four factors. What it measures, why it controls your FBA capacity, and how to read it.
Higher is better on the 0 to 1000 scale, and Amazon has historically used a threshold (commonly cited around 400) below which sellers face tighter capacity. Many sellers aim to stay comfortably above that line, and a score in the mid-hundreds and up is generally considered healthy. Amazon has adjusted the exact threshold over time, so check the current figure in your own account rather than assume.
What factors make up the IPI score?
The IPI is built from a handful of inventory-health signals: your FBA sell-through rate, your excess-inventory percentage, your stranded-inventory percentage, and your in-stock rate on replenishable products. Each measures a different way inventory can be mismanaged, and Amazon combines them into the single 0 to 1000 score. The exact weighting is not published and has changed over time.
T. Brian Jones is co-founder and CTO of Inventory Hero. He leads the engineering behind its Amazon data pipeline, demand forecasting, and the AI platform that lets sellers talk to their live inventory, sales, and supplier data in plain language.
Because it feeds the capacity Amazon grants you in FBA. A low IPI can mean tighter capacity limits, restricting how much inventory you can send in, which can leave you unable to restock a healthy SKU. A strong IPI keeps your capacity ample. It is less a vanity metric than a gate on your ability to operate, which is why it is worth managing.
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The Amazon IPI score, or Inventory Performance Index, is Amazon's 0 to 1000 rating of how well you manage your FBA inventory. The short version: it is built from a handful of inventory-health factors, it matters because it feeds the capacity Amazon grants you, and you raise it by fixing the underlying health rather than gaming a number. Below is what the score measures, why it governs your capacity, the threshold that matters, and how to read and improve it.
The IPI is a single number from 0 to 1000 that summarizes your FBA inventory health. Amazon updates it over a trailing window and shows it in your inventory dashboard. It is designed to reward sellers who keep the right amount of the right inventory moving, and to penalize the two ways that goes wrong: holding too much that does not sell, and running out of what does.
The exact algorithm and weighting are not published, and Amazon has revised both the components and the thresholds over time. So treat the specifics here as the shape of the thing, and read your own current numbers in Seller Central for the authoritative detail.
Excess inventory percentage. The share of your stock that is more than you need for current demand. High excess inventory means cash and space tied up, and it pulls the score down.
Stranded inventory percentage. Units sitting in fulfillment centers with no active, sellable listing. Stranded inventory is pure waste, and it hurts the score directly.
In-stock rate. The share of time your replenishable SKUs are actually available. Frequent stockouts lower it.
Notice the theme: two of these punish holding too much (excess, stranded), one punishes selling too slowly (sell-through), and one punishes running out (in-stock). The IPI rewards the healthy middle, which is the same balance the rest of good inventory management targets.
Concretely: say you hold 300 units of Widget A and 50 units of Widget B. Widget A sells 15 units a month, so 300 units is 20 months of cover, deep into excess territory. Widget B is stranded, sitting in a fulfillment center with no active listing. Both drag your IPI, through the excess and stranded components respectively. The fix is visible: relist Widget B to clear the stranded component, and create a removal order for the Widget A overage to bring cover down toward a sane level. In the next rolling window, both components improve and the score follows. That is the whole game in miniature, diagnose the component, fix the underlying inventory, wait for the rolling score to catch up.
One factor sellers underrate is physical size. Because capacity is measured in volume, oversized and bulky units consume far more space per unit than small ones, so a bulky slow mover does outsized damage: it eats capacity, and its slow sell-through and easy slide into excess both drag the score. The practical implication is that your bulky, slow SKUs deserve the most scrutiny; they are where excess hurts most and where clearing pays back most, both in IPI and in the capacity it frees.
The reason to care about IPI is not the number itself; it is what Amazon does with it. Your score feeds the capacity limits Amazon grants you, the ceiling on how much inventory you can have in and send to the fulfillment network:
A strong IPI generally means ample capacity, so you can restock freely.
A weak IPI can mean tighter capacity, restricting how much you can send in.
The cruel irony is the timing: capacity gets tight exactly when your inventory health is poor, which is often when you most need to restock a healthy SKU. That is why IPI is best managed proactively, not fixed in a panic when a limit bites. See restock limits for how the capacity restriction plays out in practice.
Higher is better on the 0 to 1000 scale, and the number that has mattered most is the threshold below which Amazon tightens capacity. That threshold has commonly been cited around 400, though Amazon has changed it over time (it has been higher in the past), so the safest approach is to check the current figure in your own account.1
Comfortably above the threshold: healthy. Your capacity should not be constrained by IPI.
Near or below the threshold: a warning. Tighter capacity may follow, so act on the underlying health.
The trend matters as much as the level. A falling IPI is a signal to tighten inventory management before it crosses the line.
Roughly, the bands map to outcomes like this:
IPI band
What it tends to mean
Below the threshold
Tighter capacity; you may be blocked from restocking
Near the threshold
Warning zone; capacity can constrain you soon
Comfortably above
Ample capacity; IPI is not limiting you
Top tier
Strong; the most capacity headroom
Aim to stay comfortably clear of the threshold rather than hovering at it, because capacity constraints are painful and slow to reverse.
It is worth making the cost of a low IPI concrete, because it is easy to treat the score as abstract. When a weak IPI tightens your capacity, the real bill is not the number; it is what you cannot do:
You cannot restock a winner. The direct cost is a stockout on a product that was selling, which carries lost sales plus lost rank and a slow recovery, often several times the value of the missed units.
Your best cash is stuck behind slow stock. Capacity tied up by excess and stranded units is space your fast movers cannot use, so the constraint compounds a cash problem you already had.
The fix is slow. Because IPI moves over a trailing window, you cannot repair it overnight; a limit that bites in peak season may not lift until after the season.
That asymmetry, slow to fix and painful when it binds, is the whole argument for keeping IPI comfortably healthy rather than letting it drift toward the threshold.
The IPI is not a live number; it moves over a trailing window, so both improvements and neglect show up gradually rather than instantly. Amazon does not publish the exact length of that window, but it is a rolling measure, so a single action will not move it the same day. Read your current score and its component breakdown in the Inventory Performance dashboard (the IPI gauge in Seller Central), which is also where your current threshold is shown. Practically:
Check it on a regular cadence, weekly is plenty, rather than reacting to a single reading.
Watch the trend and the components, not just the headline score, since the component breakdown tells you what is moving it.
Act on a downward trend early, because a score drifting toward the threshold is far easier to arrest than one that has already crossed it and triggered a limit.
Treating IPI as a trend to steer rather than a number to check makes it a manageable input instead of a periodic scare.
When your IPI moves, the useful question is which input drove it, because that tells you what to fix:
Score dropped and you are holding a lot? Look at excess inventory and stranded inventory.
Score dropped and you have been running out? Look at in-stock rate.
Score is mediocre across the board? Sell-through is probably the lever, meaning you are carrying too much relative to how fast it sells.
Amazon's dashboard breaks the score into its components, so you do not have to guess. Diagnose by component, then fix the underlying issue. The full playbook is in how to improve your IPI score.
It is not gameable. Because it reflects real inventory health, the only durable way to raise it is to fix the inventory, not to find a trick.
It is not only about excess. Running out of stock hurts it too, through in-stock rate, so slashing inventory to the bone can lower your IPI, not raise it.
It is not static. It moves over a trailing window, so improvements take a little time to show up, and neglect shows up gradually rather than all at once.
The threshold is not fixed forever. Amazon has changed it, so manage to a comfortable margin rather than a specific magic number.
The Amazon IPI score is a 0 to 1000 measure of FBA inventory health, built from sell-through, excess, stranded, and in-stock signals, and it matters because it governs the capacity Amazon grants you. Aim to stay comfortably above the threshold, diagnose changes by component, and fix the underlying inventory rather than chasing the number. Do that and IPI becomes a byproduct of good management rather than a constraint on it. For the step-by-step, see how to improve your IPI score; for the wider system, restock planning.
The roughly 400 IPI threshold for tighter capacity is a commonly cited figure that Amazon has changed over time (it has been higher in past periods) and may adjust again. It is not a permanent published constant; confirm the current threshold in your Seller Central Inventory Performance dashboard and Amazon's IPI help pages (sellercentral.amazon.com). ↩