The four storage-related fees to watch
Amazon storage costs come from four related charges: the monthly inventory storage fee, the aged inventory surcharge, the storage utilization surcharge and the low-inventory-level fee. The first three penalize holding too much inventory in FBA, and the fourth penalizes holding too little. Together they push sellers toward a narrow band of inventory, enough to stay in stock and no more.
Fee names, thresholds and rates change, so always check the current Seller Central fee pages before modeling costs. The logic below has been consistent and is what matters for planning.
Monthly inventory storage fee
The monthly inventory storage fee is charged per cubic foot of space your inventory occupies in FBA, based on daily average volume. Rates differ by size tier and are higher in October through December than in the rest of the year.
Because the fee is volume-based, packaging matters. Bulky packaging and oversized cartons cost you every month the unit sits. Right-sizing product packaging is one of the few levers that lowers this fee permanently.
Aged inventory surcharge
The aged inventory surcharge applies to units that have been stored in FBA beyond a set age, with charges that rise in tiers the longer inventory sits. It is charged in addition to the monthly storage fee.
Aged inventory is usually a forecasting symptom: too many units sent in at once, a slow variant, or a listing that lost momentum. The practical fix is sending smaller, more frequent replenishments so FBA only holds what will sell soon, and pulling or liquidating stock before it reaches the expensive tiers.
Storage utilization surcharge
The storage utilization surcharge applies when your inventory in FBA is high relative to how fast it sells. Amazon measures this with a storage utilization ratio, comparing average daily inventory volume with average daily shipped volume, and adds a surcharge per cubic foot once the ratio crosses a threshold. Some sellers, such as newer accounts, may be exempt.
This fee rewards exactly what an upstream buffer provides: lean FBA inventory replenished steadily from bulk storage outside Amazon.
Low-inventory-level fee
The low-inventory-level fee is the counterweight. It applies to standard-size and some other units when your FBA inventory is consistently low relative to demand, measured in days of supply against both short-term and long-term history. Amazon exempts certain cases, such as new products and very low-volume SKUs, and the exact rules are published in Seller Central.
The lesson is that running FBA too lean also costs money, so cutting inventory aggressively to dodge storage fees can backfire.
Finding the right inventory band
The right band is the range where FBA holds enough days of cover to avoid low-inventory fees and stockouts, but not so much that utilization or aged surcharges kick in. In practice that means:
- Track days of cover by SKU, not just units on hand
- Set a minimum and maximum days-of-cover target for each SKU
- Replenish on a regular cadence sized to stay between those targets
- Review aged inventory monthly and act before the next tier
- Raise targets ahead of peak periods, then lower them after
These targets should account for inbound transit and receiving time, which vary by season.
How upstream storage changes the math
Upstream storage changes the math by moving the bulk of your inventory to pallet-rate storage outside Amazon. Instead of sending a full container into FBA and watching fees build, you hold the container at a 3PL and release a few weeks of cover at a time.
You still pay for storage, but generally on pallet positions rather than per cubic foot at FBA rates, and you avoid the surcharges tied to holding too much in Amazon. The same stock can also serve DTC, Walmart or wholesale orders, so slow FBA sell-through does not leave inventory stranded.
Peak season and storage fees
Peak season changes the storage calculation in two directions at once. Storage rates rise in Q4, and Amazon typically publishes inventory deadlines for holiday sales that require inventory to be received earlier than usual. Sellers who wait until those deadlines to send stock often find that receiving has slowed and capacity is tight.
A sound peak plan raises days-of-cover targets in FBA ahead of the deadlines, but only for SKUs with proven holiday demand. Slower SKUs stay upstream, where higher Q4 storage rates do not apply, and replenish in smaller waves as sell-through shows what is moving. After peak, reverse the process: lower FBA targets, let FBA inventory sell down and resume a regular cadence before aged inventory surcharges build on holiday overbuys.
January is also the right time to review which SKUs ended the season with excess stock. Those are the units most likely to become aged inventory, and deciding early whether to remove, discount or move them to another channel saves fees later. A 3PL that receives removals and ships other channels gives you options beyond liquidation for that inventory.
Frequently asked questions
Why are Amazon storage fees higher in Q4?
Amazon charges higher monthly storage fees from October through December because space is scarce during peak season. Planning Q4 inventory around those rates helps avoid surprise costs.
What is the difference between the aged inventory surcharge and the storage utilization surcharge?
The aged inventory surcharge is based on how long individual units have been stored, while the storage utilization surcharge is based on how much total inventory you hold relative to your sales rate.
Can keeping inventory at a 3PL reduce my FBA fees?
Yes. Holding bulk inventory at a 3PL and replenishing FBA in smaller waves keeps your Amazon inventory lean, which reduces exposure to aged and utilization surcharges while keeping listings in stock.