Per-ASIN Fee Outliers, Amazon Seller Central

ASINs whose fee percentage is far above their category median. Repackaging and dimensional-weight optimisation candidates. How to read it, why it matters, and how to act on it.

Metrics type: Supporting Metrics • Category: FBA Economics

At a glance

The ASINs Amazon is taking a disproportionate cut of. The card flags products whose total fee percentage runs well above the typical level for their category (default more than twice the category median), and lists them as repackaging and dimensional-weight optimisation candidates. These are the SKUs where a packaging redesign, a size-tier drop, or a price adjustment recovers the most margin per unit of effort. It turns the blended fee picture into a targeted worklist.

What it counts	ASINs whose fee percentage (fees as a share of selling price) exceeds a multiple of the category median, default more than 2x. It surfaces the products where fees are abnormally high relative to peers.
Which fees	The fee percentage typically blends FBA fulfilment fee and referral fee against selling price; storage can be included depending on configuration. The point is total fee load per ASIN, not one fee in isolation.
Why “category median”	Fee norms vary hugely by category. A 30% fee is normal for a cheap, bulky item and alarming for a premium one. Comparing each ASIN to its own category median, rather than a flat threshold, finds the genuine outliers.
Why these ASINs are fixable	High fee percentage usually comes from one of three things: oversized or overweight packaging (raising FBA size tier), a low selling price spreading fixed fees thinly, or a high-referral-fee category. The first is a packaging fix, the second a pricing fix, the third a product-mix decision.
FBA vs FBM	Most relevant to FBA, where fulfilment fees are size and weight driven. FBM ASINs carry your own shipping cost instead, which this card does not see.
Reading the table	Sort by fee percentage descending and by velocity. A high-fee-percentage, high-velocity ASIN is the top repackaging priority; high-fee, low-velocity ASINs may be discontinue candidates.
Dimensional weight	FBA fees use the greater of actual and dimensional weight. A light but bulky item is penalised, removing void fill or shrinking the box can drop a size tier and the fee with it.
Currency / unit	percent
Time window	30D (rolling 30 days)
Alert trigger	>2x category-median fee %
Roles	owner, finance

Calculation

Calculated automatically from your Amazon Seller Central data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.

Worked example

A homeware brand on Amazon UK, FBA, 30-day window ending 01 May 26. Category median fee percentage shown for context. All numbers illustrative.

ASIN	Selling price	Total fee	Fee %	Category median	Multiple	Verdict
Plastic storage box, XL	£14.99	£7.80	52%	24%	2.2x	Oversized packaging, flagged
Throw cushion	£19.99	£5.40	27%	25%	1.1x	Normal, not flagged
Folding laundry basket	£9.99	£5.90	59%	24%	2.5x	Bulky + cheap, flagged
Glass vase	£29.99	£8.10	27%	26%	1.0x	Normal
Plastic hangers 50pk	£12.99	£8.40	65%	24%	2.7x	Oversize + low price, flagged
Flagged outliers (>2x median)						3 ASINs

Five things to notice:

1. All three flagged ASINs share a profile: cheap and bulky. The storage box, laundry basket, and hanger pack are all low-priced, awkwardly-sized items. That is the classic FBA fee trap, dimensional weight pushes them into a high size tier while the low price means the fee eats a huge share. These are textbook repackaging candidates.
2. The cushion and vase are correctly left alone. Both sit at the category median. The card deliberately compares to category norms, so it does not waste your attention on ASINs whose fee is simply normal for their type.
3. The laundry basket at 59% is barely breaking even. With 59% of price going to Amazon before cost of goods, this SKU may be unprofitable. The choice is repackage (collapse the basket flat to drop a size tier), reprice up, or discontinue.
4. Dimensional weight is the common lever. All three flagged items are light but bulky, so they are charged on dimensional weight, not actual weight. Compressing or flat-packing them can drop the size tier and the fee in one move.
5. The alert fired on a clear list. Three ASINs over >2x category-median fee % is a concrete worklist, not a vague warning. The action is a packaging review of those three, prioritised by their unit volume.

Sibling cards merchants should reference together

This card is the targeted worklist; pair it with the totals and the bottom line:

Card	Why pair it with Per-ASIN Fee Outliers
FBA Fees	The aggregate fulfilment-fee total these outliers contribute to.
Fees % of Revenue	The portfolio ratio; fixing outliers brings this down.
Referral Fees	The percentage component; high-referral categories drive some outliers regardless of packaging.
FBA Storage Fees	Bulky outliers also cost the most to store; the two problems often overlap.
Net Revenue (after fees + refunds)	The margin these outliers erode; quantifies the prize from fixing them.
Top ASINs by Revenue	Cross-check velocity so you repackage the high-volume outliers first.

Reconciling against Amazon Seller Central

Where to look in Amazon Seller Central:

Seller Central → Inventory reports with the FBA Fulfillment Fee and Referral Fee columns per ASIN, plus the Fee Preview report. Compare each ASIN’s fee against its selling price to derive the fee percentage; the card does this and compares to the category median for you.

The FBA Revenue Calculator lets you model the fee impact of a smaller package per ASIN, which is the natural next step after this card flags a candidate.

Timing, settlement, and reporting-lag table:

Topic	Detail
Timezone	Fee data is order / charge based; Vortex IQ aligns to your configured reporting timezone. Boundary-day orders can shift the per-ASIN average slightly.
Category median basis	The card computes a category median to compare against. The median moves as your and the category’s mix changes, so an ASIN can cross or fall under the 2x line without its own fee changing.
Estimate vs actual fee	Fee previews are estimates; re-measured dimensions can change the actual fee at settlement, shifting an ASIN’s fee percentage.
Refresh cadence	The card recomputes on the standard data cadence; a packaging change you make takes effect once Amazon re-measures and new orders flow through.

Why our number may legitimately differ from a manual calc:

Reason	Direction	Why
Fee components included	Either	Whether storage is folded into the fee percentage changes the value; the card follows its configured definition.
Category median definition	Either	A hand calc against a flat threshold will not match the card’s category-relative comparison.
Price basis	Either	Using list price vs realised ASP (net of coupons) changes the fee percentage denominator.
Re-measured dimensions	Small	Amazon re-measurement shifts actual fees away from previews for affected units.

Cross-connector reconciliation against other connectors the same seller may run:

Card	Expected relationship	What causes legitimate divergence
ebay.fees-of-revenue	Different fee model. eBay’s final-value fee is a flat-ish percentage, so eBay has fewer “fee outliers” from packaging; the outlier concept is specific to FBA’s size-and-weight pricing.	Use as a marketplace cost peer only; the outlier mechanic does not translate directly.
shopify.total_revenue	Independent channel. DTC fulfilment cost is your own carrier spend; bulky items cost more to ship from your own warehouse too.	No reconciliation, but a bulky FBA outlier is often a bulky DTC shipping outlier as well; fixing packaging helps both.

Known limitations / merchant FAQs

Why compare to the category median instead of a fixed percentage? Because fee norms vary enormously by category. A 30% fee is normal for a cheap, bulky homeware item and alarming for a premium electronics item. A flat threshold would flag entire categories as outliers; comparing each ASIN to its own category median finds the genuine anomalies.

An ASIN got flagged but I cannot change its size. What now? If packaging cannot shrink, your levers are price (raise it so the fee is a smaller share), bundle (sell a multipack so the fee is spread over more value), or discontinue if it is unprofitable and low-velocity. Repackaging is the first option, not the only one.

Does this include the referral fee or just FBA fees? The fee percentage typically blends FBA fulfilment and referral fees against the selling price, so it reflects total fee load. Storage may be included depending on configuration. The aim is to find ASINs Amazon is taking a disproportionate total cut of.

What is dimensional weight and why does it matter here? FBA charges on the greater of actual weight and dimensional (volumetric) weight. A light but bulky item is billed on its size, not its mass. Removing void fill or flat-packing such an item can drop a size tier and the fee, which is why these ASINs are repackaging candidates.

Can I change the alert threshold? Yes. The >2x category-median fee % default is configurable per profile in the Alert Rules tab. Tighten it (for example 1.5x) to catch milder outliers, or loosen it to focus only on the worst offenders.

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Tracked live in Vortex IQ Nerve Centre

Per-ASIN Fee Outliers is one of hundreds of KPI pulses Vortex IQ tracks across Amazon Seller Central and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English.

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