Amazon Low Inventory Level Fee: Rules and Rates

The Amazon low inventory level fee is a per-unit charge on standard-size FBA products that hold too little stock relative to how fast they sell. It is not a storage fee, and it is not a penalty on slow sellers. It is close to the opposite: a charge on products that move well and run thin.

When Amazon charges the low inventory level fee

There is one rule, and it has two clocks. Amazon explains it in Seller Central: it calculates the historical days of supply metric over the short term (last 30 days) and the long term (last 90 days), and only assesses the fee if both are below 28 days.

Both. If your 90 day figure is 20 days but you have just restocked and the 30 day figure is 31, the fee does not apply. That is deliberate. Amazon describes the design as providing flexibility, because you can avoid the fee through short-term improvements.

Historical days of supply is average daily inventory divided by average daily units shipped, calculated over each of those two windows.

What the low inventory level fee costs

The fee is charged per unit sold, and it steps down as your days of supply rise towards 28. For a small standard-size product at 0 to 14 historical days of supply, the published rate is $0.89 per unit. The full table, by size tier and by band, sits in the FBA fee reference inside Seller Central, which only opens with a signed-in session.

As of the 2026 referral and FBA fee update, effective January 15, 2026, FBA fees rose by an average of $0.08 per unit sold, under 0.5% of an average item's selling price, and Amazon introduced no new fee types. The low inventory level fee kept its structure.

Which SKUs are under 28 days of supply?

See my supply days

A complete example

A small standard-size SKU, under 16 oz, sells 12 units a day.

• Average on-hand inventory over the last 30 days: 120 units. 120 divided by 12 is 10 historical days of supply.
• The same calculation over the last 90 days gives 13 days.
• Both are below 28, so the fee applies, and 10 days puts the SKU in the lowest band: $0.89 per unit.
• You sell 360 units that month. The fee adds $320.40 on top of the fulfillment fee you already pay on those same 360 units.

Now push the 30 day figure above 28 days by sending stock in. The long term figure is still 13, but the short term one is not, so the fee stops. Inside a single month that is the only lever that works.

Who is exempt from the low inventory level fee

Amazon lists the exemptions in its own announcements:

• Products that sold fewer than 20 units in the past 7 days, a rule in force since May 15, 2024.
• New professional sellers, for their first 365 days.
• New-to-FBA products, for their first 180 days, with FBA New Selection enrollment.
• Products auto-replenished by Amazon Warehousing and Distribution.
• Slower-moving items, which the 2026 fee update confirms stay exempt, with the trade-off that they may see slower delivery promises or limited nationwide availability.

The fee itself has applied since April 1, 2024. Charges incurred between April 1 and May 14, 2024 were credited back.

What to do with this

Amazon hands you the answer already calculated. The Minimum Inventory Level metric on the FBA Inventory page is a machine-learning estimate of the minimum units per product you should hold. Amazon states that sellers who stay above it see a 15% increase in sales over a four-week period on average, though results vary. Staying above that line is the same action that keeps both days-of-supply clocks above 28.

Two neighbours of this fee are worth reading next. Why a low inventory level fee shows up while your stock sits in receiving covers the case where you did restock and got charged anyway. Every FBA fee with its effective date puts this charge next to the rest of them, and the five clocks of FBA inventory management covers the other charges that start on their own.

“We will calculate the historical days of supply metric over the short-term (last 30 days) and long-term (last 90 days) and only assess the fee if both are below 28 days.”

— Amazon Seller Central ↗

#FBA#fees#inventory#evergreen

👋Hey! I'm Amara

Press at SellerKey.co

☕ Espresso. Never a latte macchiato.

I cover Amazon fee and policy changes: what changed, when it applies and where Amazon published it.

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