Overview

Amazon introduced a “low inventory level fee” for Fulfillment by Amazon (FBA) sellers in April 2024. The charge applies to standard‑size items that fall below a 28‑day supply threshold, adding up to $1.11 per unit sold. Sellers who rely on ultra‑lean stock levels must adjust their replenishment tactics to avoid unexpected cost erosion.

Key Points

• Per‑unit surcharge range — Fees vary from $0.32 to $1.11 for each unit sold, depending on product size and how far the supply dips below the 28‑day benchmark.
• Dual‑threshold trigger — Both the 30‑day short‑term and the 90‑day long‑term “days of supply” metrics must drop under 28 days before the fee is assessed, preventing a single brief stockout from incurring charges.
• Standard‑size only — The penalty is limited to items classified as standard size; oversize, hazardous, or special‑handling SKUs remain exempt.
• New‑listing exemption — ASINs with fewer than 90 days of sales history at Amazon fulfillment centers are not subject to the fee, giving fresh products time to generate reliable demand data.
• Fee scales with scarcity — Supplies between 21‑28 days trigger the lowest tier (≈ $0.32 per unit for small items), while inventories under 14 days can attract the maximum $1.11 per unit, dramatically affecting low‑margin goods.
• Rolling calculation — Amazon updates the two supply metrics daily, so any prolonged under‑stocking results in the fee being applied to every unit sold during that period.

How the Low Inventory Level Fee Works

1. Track short‑term supply — Amazon calculates “days of supply” for the last 30 days based on recent sales velocity and on‑hand inventory.
   Example: A toy that sold 300 units in the past month with 6,000 units in the warehouse shows a 30‑day supply of 20 days.
2. Track long‑term supply — A parallel 90‑day rolling metric is computed using the same formula but over a three‑month window.
   Example: The same toy’s 90‑day supply might be 25 days because sales were slower in the preceding two months.