The Amazon IPI score — the Inventory Performance Index — is a 0-to-1,000 number that grades how efficiently you run FBA inventory. Amazon defines it as “a score that measures your Amazon inventory performance over time,” and says the score, which ranges from 0 to 1,000, is largely based on your ability to keep sold and on-hand (fulfillable or sellable) inventory in balance (sell.amazon.com, checked 2026-07-30). Amazon names four component metrics — excess inventory, sell-through, stranded inventory, and in-stock rate — in a long-standing Seller Forums post (checked 2026-07-30); its public pages define only the first three. The score feeds your monthly FBA capacity limit — the cubic footage you may keep in Amazon’s network.
This guide separates what Amazon publishes from what the rest of the internet asserts, breaks the score into its four levers, and gives a repair sequence ordered by how fast each lever moves.
One distinction first: IPI is an inventory metric, not the Account Health Rating — a separate 0-to-1,000 score measuring policy compliance and deactivation risk. Same numeric range, entirely different inputs.
Fact Block: What Amazon Publishes, and What It Doesn’t
The Seller Central help articles that define IPI in detail sit behind a login — we confirmed on 2026-07-30 that both the IPI and FBA capacity limits help pages redirect to a sign-in wall. What follows comes from pages readable without an account.
On Amazon’s public seller site (checked 2026-07-30):
- IPI is “a metric for Amazon sellers that measures how efficiently you manage your FBA inventory—similar to a credit score for your inventory efficiency” (sell.amazon.com).
- The score “is largely based on your ability to: Maintain balanced levels between sold and on-hand (fulfillable or sellable) inventory; Avoid excess and aged inventory, and long-term storage costs; Efficiently address listing issues; Maintain popular products to meet customer demand and maximize satisfaction” (sell.amazon.com).
- “FBA capacity limits are influenced by sellers’ IPI scores, as well as other factors such as sales forecasts for their ASINs, shipment lead time, and fulfillment center capacity” (sell.amazon.com).
On the public Seller Forums, where Amazon staff post without a paywall (checked 2026-07-30): a long-standing moderator post from the account SEAmod names the four component metrics — excess inventory percentage, FBA sell-through rate, stranded inventory percentage, and FBA in-stock rate — and says the score “combines the past three months of sales, inventory levels, and costs into a single rolling metric updated weekly” (Seller Forums thread). The forum dates that post at roughly eight years old, so read its numbers as history, not current policy — more on that below.
Not published anywhere public: how the four factors are weighted. Amazon has never released the formula, the weights, or the mapping from lever values to points. Any article that tells you excess inventory is “35% of your score” is presenting a guess as a fact. You know the direction each lever pushes, not its coefficient.
The Four Levers Behind Your IPI Score
| Lever | Amazon’s definition (checked 2026-07-30) | Which way it pushes |
|---|---|---|
| Excess inventory | “Items are considered to be excess if there’s over 90 days of supply in comparison to customer demand” | More excess, lower score |
| FBA sell-through rate | “The number of units sold and delivered over the past 90-days divided by the average number of sellable units in fulfilment centers” | Higher sell-through, higher score |
| Stranded inventory | “A product in FBA fulfillment centers that doesn’t have an active offer” | More stranded units, lower score |
| FBA in-stock rate | The “percentage of time that replenishable FBA products have been in stock for the past 30 days, weighted by the number of units sold in the past 60 days” | Higher in-stock rate, higher score |
Definitions for excess, sell-through, and stranded are quoted from sell.amazon.com; the in-stock rate wording comes from the SEAmod Seller Forums post linked above.
Two structural facts follow, and they explain most of the frustration sellers report.
The score is a rolling window, not a snapshot. Sell-through looks back 90 days; in-stock rate looks back 30 days weighted by 60 days of sales. A removal order you place today cannot un-hold inventory you were holding in May. Amazon’s own framing of the failure mode is a turnover target: its list of things that lower your score leads with “You have too much inventory and can’t turn it over every 30 to 60 days.”
The levers fight each other. Cutting inventory hard fixes excess and sell-through, then walks you into stockouts that damage in-stock rate. Sellers who yo-yo between “too deep” and “out of stock” hold a mediocre score for quarters while feeling like they are constantly fixing it. The stable position is narrower coverage on fewer SKUs, restocked more often — a forecasting problem before it is an IPI problem, and the reason restock forecasting software exists.
The Gate: What a Low Score Actually Costs You
Here is where most IPI advice is out of date: the storage-limit regime IPI was famous for no longer exists in its original form. Amazon announced on the Seller Forums: “Effective March 1, 2023, we’re replacing the weekly restock limit and quarterly storage limit with a single monthly capacity limit per storage type” (News_Amazon, Seller Forums, checked 2026-07-30). Capacity is measured “in cubic feet (vs. number of units)” (sell.amazon.com), and usage “will consider your inventory on-hand at Amazon and open shipments on the way to our fulfillment centers” (Dominic_Amazon, Seller Forums).
Under that system, IPI is an input to a limit rather than a pass/fail gate:
| Account situation | What Amazon says applies |
|---|---|
| Individual selling account | “Capacity limit of 15 cubic feet; this limit doesn’t change and is not eligible to be increased” |
| New professional account, in FBA under 39 weeks | “New professional selling accounts (active in FBA for less than 39 weeks) don’t receive FBA capacity limits” |
| Professional account, in FBA over 39 weeks | Limits “based on IPI score and sales performance. Sellers with consistently higher IPI scores receive higher capacity limits” |
Table source: Dominic_Amazon, Refresher: FBA Capacity Limits & How They Work, Seller Forums, read logged out 2026-07-30.
Three consequences worth planning around:
- Timing. “Capacity limits for the upcoming month will be announced in the third full week of each month via the Capacity Monitor in Seller Central” (sell.amazon.com). Purchase orders placed on a 60-to-120-day import lead time are committed long before you know the limit they will land under.
- Overage fees. They “are calculated based on the highest estimated or confirmed limit that we provided for the given period” — so the estimate you were shown earlier in the cycle works in your favour if the confirmed limit comes in lower. Usage counts open shipments, but fees “will apply if your on-hand inventory in Amazon’s fulfillment centers, not including open shipments, exceeds your capacity limit” (News_Amazon, Seller Forums, checked 2026-07-30) — inbound stock eats your limit without triggering the fee.
- Buying your way out is possible, but priced. Through Capacity Manager, “sellers can request additional capacity based on a reservation fee that they specify,” granted “starting with the highest reservation fee per cubic foot until all capacity available under this program has been allocated.” Amazon adds that “performance credits are designed to offset up to 100% of the reservation fee, so sellers don’t pay for the additional capacity as long as their products sell through” (sell.amazon.com, checked 2026-07-30). Reserved space that does not sell through is space you paid twice for — once in the reservation, once in storage and fee drag on unit economics.
About That “400 Minimum”
Search for an IPI threshold and you will be told the minimum is 400 — or 350, depending on which 2026 article you land on. Both numbers circulate widely; neither is published as a current minimum on any public Amazon page we could reach on 2026-07-30 — the only 350 that exists there sits in a pre-2023 moderator post, quoted below.
The only threshold numbers Amazon has stated publicly on a page readable without login are in that eight-year-old moderator post: “An IPI score above 450 means your FBA inventory is performing well, and a score above 550 indicates your inventory is a top performer,” and “a score under 350 could lead to limits being placed on your FBA storage and to overage fees.” Those sentences describe the pre-2023 storage-limit system, which Amazon has since replaced. Quoting them undated as current policy is how a 2018 number becomes a 2026 “fact.”
What holds up today is the directional statement Amazon still publishes: higher IPI, higher capacity limit, and “the higher your IPI score, the better.” Manage toward headroom rather than a rumoured cut-off, and check your own Capacity Monitor for the number that actually binds you. Third-party targets in the 500-plus range are opinion, not policy.
The Repair Sequence, Fastest Lever First
Work in this order. It is sequenced by how quickly each action shows up in the score, given the rolling windows above.
- Clear stranded inventory this week. Units without an active offer occupy cubic feet, accrue storage, sell nothing, and drag the score. The Fix Stranded Inventory view in Seller Central lists the cause per ASIN — suppressed listing, pricing error, category restriction, deleted offer — and relisting restores them to sellable status with no inbound shipment. This is the only lever you can move in days.
- Stop the bleeding on inbound. Freeze replenishment on any SKU already carrying more than 90 days of supply. Every unit you send to a slow SKU worsens excess and sell-through, and the rolling window keeps it worsening them for the next quarter.
- Liquidate or remove the dead tail, deliberately. Removal, disposal, and liquidation cost money; so does holding, and aged inventory surcharges climb with time on hand. The rule is comparative: if the margin left after markdown beats the storage cost of holding to a realistic sell-out date, mark it down; if not, get it out. Do not let a sunk landed cost pin units in a fulfillment center for another two quarters.
- Discount to sell through, not to zero. A price cut that clears 90 days of cover in 30 improves sell-through, excess, and cash at once. A cut deep enough to reset your price history costs more than the score gain — check the trailing price band with a price-tracking tool first.
- Protect in-stock rate on the winners. In-stock rate is weighted by units sold, so a stockout on your top SKU costs far more than one on a long-tail ASIN. Rank by sales velocity, not by unit count.
- Then fix the forecast. Steps one through five are triage; only better reorder timing keeps the score up. Shorter, more frequent shipments beat one big replenishment for every lever except your own shipping labour. A neutral, workflow-organised directory of tools in this category is maintained at AMZFinder’s inventory and operations workflow page.
Common Mistakes
- Treating IPI as a compliance score. It changes how much you may store, not whether your account survives. Account risk lives in the Account Health Rating.
- Reacting to the weekly number. The inputs are 30-to-90-day rolling windows; week-to-week wobble is mostly noise. Judge your actions monthly.
- Cutting deep across the board. Slashing every SKU uniformly protects excess and destroys in-stock rate on the SKUs that fund the business.
- Sending bulky, slow SKUs. Capacity is measured in cubic feet, so an oversize slow mover consumes limit out of proportion to its revenue. Check your FBA size tier mix when capacity is tight, not just unit counts.
- Assuming a number from a blog post is a policy. Thresholds quoted without a dated Amazon source are usually recycled from the pre-2023 storage-limit era.
Frequently Asked Questions
What is a good Amazon IPI score in 2026?
Amazon publishes no current minimum on any page readable without a Seller Central login (checked 2026-07-30). The only Amazon-stated bands available publicly — above 450 “performing well,” above 550 “a top performer,” under 350 risking storage limits — come from a moderator post that predates the March 2023 capacity system. Directionally, higher is better; the practical target is enough headroom that your capacity limit never constrains your restock plan.
How often does the IPI score update?
Amazon’s moderator post describes it as “a single rolling metric updated weekly,” built from “the past three months of sales, inventory levels, and costs” (checked 2026-07-30). Because the inputs are 30-to-90-day windows, a weekly update does not mean a weekly reaction to what you did yesterday.
How is the IPI score calculated?
Amazon names four component metrics — excess inventory percentage, FBA sell-through rate, stranded inventory percentage, and FBA in-stock rate — but has never published how they are weighted or how each maps to points. Treat any specific percentage breakdown you see elsewhere as an estimate.
Does a low IPI score still cause storage limits?
Not in the old form. Since 1 March 2023, Amazon has used “a single monthly capacity limit per storage type” measured in cubic feet, and IPI is one of several inputs into that limit alongside ASIN sales forecasts, shipment lead time, and fulfillment center capacity. A low score means less room and possible overage fees, not an automatic block.
Does IPI affect my Account Health Rating?
No. They are separate scores with separate inputs. IPI grades inventory efficiency and drives capacity; AHR grades policy compliance and drives deactivation risk.
Conclusion
IPI rewards one behaviour: holding the smallest amount of inventory that still keeps your sellable products in stock. Clear stranded units first because it is the only fast lever, stop replenishing anything already past 90 days of cover, decide on the dead tail with arithmetic instead of hope, then fix the forecasting that put you there. Watch your Capacity Monitor for the number that actually constrains you, and treat any undated threshold as a rumour until you find it on a dated Amazon page.