{"id":14421,"date":"2025-05-23T06:10:02","date_gmt":"2025-05-23T06:10:02","guid":{"rendered":"https:\/\/zonhack.com\/?p=14421"},"modified":"2026-08-31T13:07:40","modified_gmt":"2026-08-31T13:07:40","slug":"amazon-inventory-management","status":"publish","type":"post","link":"https:\/\/zonhack.com\/zh\/amazon-inventory-management\/","title":{"rendered":"Amazon Inventory Management: The Metrics That Decide Capacity"},"content":{"rendered":"

Amazon inventory management<\/strong> is the practice of keeping enough stock in the network to sell without
\nholding so much that storage fees, surcharges, and capacity limits start working against you. It is a
\nbalancing act with a penalty on both sides, which is what makes it harder than it sounds.<\/p>\n

The two failure modes cost differently.<\/strong> Running out costs you sales and rank, and rank is slower to
\nrecover than stock. Holding too much costs you storage fees, aged-inventory surcharges, and capacity
\nyou cannot use for products that would sell. In our experience sellers fear the first and quietly bleed
\nfrom the second.<\/p>\n

The metrics that actually matter<\/h2>\n

Four numbers. Everything else is downstream of these.<\/p>\n

Inventory Performance Index<\/h3>\n

IPI is Amazon’s composite score for how well you manage inventory<\/strong>, and it feeds into the storage
\ncapacity you are granted. It reflects excess inventory, sell-through, stranded listings, and in-stock
\nrates rather than any single one of them.<\/p>\n

Amazon has changed how capacity is granted more than once, moving toward capacity limits measured in
\ncubic feet with IPI as an input rather than the sole gate. Check your current limit and its basis in
\nSeller Central<\/strong> rather than trusting a threshold quoted in an article, including this one, because the
\nmechanism has been revised repeatedly.<\/p>\n

Sell-through rate<\/h3>\n

Units sold over a period against average units held. The single most honest measure of whether stock is working.<\/strong> It is the first number I look at on any account, ahead of revenue, ahead of IPI, and ahead of whatever the dashboard has decided to put at the top, because a high sell-through rate on modest volume describes a healthy operation while the reverse describes capital slowly turning into storage fees. Simple to calculate. Rarely looked at.<\/p>\n

Low sell-through on a SKU means capital sitting still while incurring fees. It is also the number that
\ntells you a product is finished before your instincts do.<\/p>\n

Weeks of cover<\/h3>\n

How many weeks your current stock lasts at current velocity. Somewhere between 6 and 10 weeks is a
\ncommon working target<\/strong>, and the right figure for you depends entirely on your lead time.<\/p>\n

The arithmetic that matters: weeks of cover must exceed your total lead time plus a safety buffer.<\/strong>
\nIf manufacturing takes 30 days and freight takes 40, a 6-week cover is already too thin, and no amount
\nof careful reordering fixes a structural gap.<\/p>\n

Stranded inventory<\/h3>\n

Units in a fulfillment center attached to a listing that cannot sell: suppressed, inactive, or broken.
\nThis is the cheapest problem on the list to fix and the most commonly ignored<\/strong>, because nothing
\nalerts you loudly.<\/p>\n

Check it weekly. Our guide to
\nfixing inactive or suppressed listings<\/a>
\ncovers the causes, and I’ve found most stranded inventory traces to something that took 5 minutes to
\nrepair once somebody looked.<\/p>\n

The fees that punish bad inventory management<\/h2>\n

Worth naming, because they arrive quietly on a statement rather than as a warning. Nobody emails you about them.<\/p>\n

Monthly storage fees<\/strong>, charged per cubic foot and higher in the final quarter of the year. Slow stock
\ncosts more in Q4 precisely when space is scarcest.<\/p>\n

Aged inventory surcharges<\/strong> on units held beyond defined age thresholds. These escalate with age and
\nare the mechanism that makes hoarding genuinely expensive.<\/p>\n

Low-inventory-level fees<\/strong> on products held too thin relative to demand, which is the counterweight
\nAmazon added so that the answer to storage fees is not simply holding nothing.<\/p>\n

Removal and disposal fees<\/strong> when you take stock out, which is why “just remove it” is a decision with
\na cost rather than a free escape.<\/p>\n

The trap is that the first two push you to hold less and the third pushes you to hold more.<\/strong> There
\nis no setting that avoids all of them. There is only a range, and finding your range is the actual work.<\/p>\n

A working routine<\/h2>\n

What I’d do rather than what a dashboard suggests.<\/p>\n

Weekly:<\/strong> check stranded inventory, check restock recommendations against your own lead times rather
\nthan accepting them, and check for listings that have gone inactive.<\/p>\n

Monthly:<\/strong> review sell-through by SKU and identify the bottom decile. Decide something about each one.
\nDeciding nothing is the default and it is what produces aged inventory.<\/p>\n

Quarterly:<\/strong> review lead times against reality rather than against what your supplier says, and adjust
\nreorder points. In our experience supplier lead times drift longer without anyone announcing it.<\/p>\n

Before Q4:<\/strong> get slow stock out before storage fees rise and capacity tightens. The decision is
\ncheaper in September than in November, and it is the same decision.<\/p>\n

Reorder points, worked through once<\/h2>\n

The one calculation worth doing by hand before trusting any tool with it.<\/p>\n

Reorder point = (daily velocity x total lead time in days) + safety stock.<\/strong><\/p>\n

Take a product selling 20 units a day. Manufacturing runs 30 days, sea freight 40, and receiving at the
\nfulfillment center takes another 7. Total lead time: 77 days. That is 1,540 units consumed before a new
\norder lands. Add a safety buffer of, say, 3 weeks at current velocity, another 420 units, and your
\nreorder point sits near 1,960 units.<\/p>\n

Now the uncomfortable part. If you reorder at 800 units because that felt like plenty, you will stock
\nout for roughly 8 weeks, and no dashboard warned you because the dashboard was watching stock rather
\nthan watching lead time.<\/p>\n

Three refinements worth applying:<\/p>\n