📋 Overview
Slow-moving FBA stock does not just sit there quietly — once units pass a certain age in Amazon’s fulfillment centers, they start collecting an aged inventory surcharge on top of your normal monthly storage fees, and the rate climbs the longer they stay.
This article explains how Amazon measures inventory age, where to see your at-risk units in Seller Central, and a repeatable monthly process for clearing, repricing, or removing stock before the surcharge compounds.
🎯 Who This Is For
🌱 Beginner sellers
- You sent your first FBA shipments and are seeing storage-related charges you did not expect.
- You are not sure where Amazon reports how long each unit has been sitting.
- You want a simple monthly habit that keeps fees from surprising you.
🚀 Advanced sellers
- You manage dozens or hundreds of ASINs and need a rule-based way to decide which aged units to discount, liquidate, or remove.
- Your Inventory Performance Index (IPI) is drifting and you want to know which lever actually moves it.
- You are planning post-seasonal cleanup and want the exit decision made before the next surcharge assessment.
🔑 Key Concepts You Need to Know
📅 Inventory age
The number of days a unit has been in an Amazon fulfillment center. Amazon ages units on a first-in, first-out basis, so shipping in fresh stock does not reset the clock on units already sitting in the network.
💰 Aged inventory surcharge
A monthly charge applied to FBA units that have exceeded an age threshold, assessed in addition to your regular monthly inventory storage fees. The surcharge is tiered by age: 181–270 days, 271–365 days, 12–15 months, and 15+ months. Rates increase with each tier and vary by product size, so confirm the current rates in Amazon’s published FBA fee schedule before you model a decision.
📈 Sell-through rate
Units shipped over a trailing period divided by the average units on hand in fulfillment centers. Low sell-through is what produces aged inventory in the first place, and it is one of the inputs behind your IPI.
🧮 Inventory Performance Index (IPI)
Amazon’s rolling score of how efficiently you use FBA storage. The minimum threshold is 400. Falling below it can trigger storage restrictions, and Amazon applies those restrictions when your score drops rather than waiting for a fixed quarterly review date.
🏭 Capacity and restock limits
Limits on how much you can send in are set at the storage-type level — standard-size, oversize, apparel, footwear — not per individual ASIN. Amazon calculates them from your IPI score, sales forecasts, and fulfillment-related factors. Aged stock consumes capacity you could be using for products that actually move.
🛠️ Step-by-Step Guide
1️⃣ Pull your inventory age data
In Seller Central, open the Inventory Age report in the Fulfillment reports section. It breaks your FBA units into age bands and flags what is already accruing, or about to accrue, a surcharge.
A good result: a spreadsheet listing every ASIN with units in each age band, plus your current available quantity. If you need to reconcile quantities or trace what happened to specific units, use the Inventory Ledger Report under Reports > Fulfillment > Inventory Ledger.
2️⃣ Calculate days of cover for each aged ASIN
Divide units on hand by your average daily sales over the last 30 to 60 days. An ASIN with 400 units and two sales a day carries 200 days of cover — that stock will hit the next surcharge tier long before it sells out at the current rate.
This number, not gut feel, is what tells you whether an ASIN can be sold through or has to be exited.
3️⃣ Sort each ASIN into one of four actions
- Sell through as-is — cover is short enough that units clear before the next tier.
- Accelerate — profitable product, too much cover; discount or advertise to raise velocity.
- Partial exit — keep a healthy quantity, remove or liquidate the excess.
- Full exit — the product does not sell at any price you can defend; get it out.
Make the call on paper before you touch pricing, or you will end up discounting products that never needed it.
4️⃣ Accelerate velocity with targeted discounts
Use the Price Discounts tool under Advertising to run a time-boxed markdown on the specific aged ASINs, or set a lower price directly in Manage Inventory. Coupons are another option, but they carry a flat fee per coupon plus a percentage of coupon-attributed sales — check the current amounts in Seller Central before you commit.
To show a strike-through reference price, the discount generally needs to be at least 5% off. A good result is a measurable lift in daily units within one to two weeks, not just more page views.
💡 Pro Tip: Model the markdown against the surcharge you would otherwise pay across the remaining months of cover. Selling at a thin margin today often nets more than holding for full price into a higher age tier.
5️⃣ Put advertising behind stock you intend to keep
For products worth defending, pair the discount with Sponsored Products so the lower price actually gets impressions. Review results in Measurement & Reporting > Sponsored ads reports and judge the campaign on units moved and days of cover removed, not only on ACoS.
Do not do this for products you have already decided to exit — you are then paying twice to clear inventory you did not want.
6️⃣ Create removal, liquidation, or disposal orders early
From Manage Inventory, select the affected ASINs and use the removal action to return units to an address you specify, send them to Amazon’s liquidation option, or dispose of them. Each path has its own per-unit fee, published in Amazon’s fee schedule.
Removals are not instant. Submit them well ahead of the next monthly fee assessment so the units are physically out of the network, not merely requested. A good result: your available quantity for that ASIN drops to your target level and no further age tiers are reached.
💡 Pro Tip: Compare three numbers before exiting — expected net proceeds if you discount and sell through, expected recovery from liquidation, and the removal or disposal fee plus any inbound freight if you plan to resell elsewhere. The cheapest-looking option on the surface is often not the best net outcome.
7️⃣ Fix the inbound quantity that created the problem
Aged inventory is almost always a replenishment decision made months earlier. Recalculate reorder quantities from actual sell-through, shorten your reorder cycle, and send smaller, more frequent shipments where your supplier terms allow.
Watch your storage-type capacity in Seller Central so you are not committing space to slow ASINs at the expense of fast ones.
8️⃣ Make this a fixed monthly review
Put a recurring date on your calendar, at least a few weeks before Amazon’s monthly fee assessment, to rerun steps 1 through 3. A good result is that units entering the first surcharge tier are the exception you deliberately accepted, not a discovery you make on your fee report.
💼 Real-World Examples
🌿 A newer seller with a seasonal miss
Situation: A seller with 12 ASINs sends in a large fourth-quarter buy of a gift-oriented item. Post-holiday demand collapses and roughly 600 units remain, all inbound on the same date.
Action: In February they pull the age report, see every unit on the same clock, and calculate about 300 days of cover. They discount 40% of the quantity through the Price Discounts tool, keep a small buffer for steady baseline demand, and submit a removal order for the remainder before the units reach the 181-day band.
Result: Storage costs stop growing month over month, and capacity frees up for the two ASINs that actually turn. The seller absorbs a margin hit on the discounted units but avoids carrying the rest into escalating surcharge tiers.
🏗️ A mid-size seller with catalog drift
Situation: A seller with roughly 80 ASINs notices IPI sliding toward the 400 threshold. The age report shows a long tail: dozens of ASINs with small quantities that have quietly sat for over a year.
Action: They set a rule — any ASIN with more than 180 days of cover and less than one sale per week gets fully exited. Higher-volume ASINs with excess quantity get a partial removal plus a short discount window, supported by Sponsored Products only where margin allows.
Result: Aged units fall sharply over the following two fee cycles, sell-through improves as the denominator shrinks, and the IPI trend reverses over the following weeks. The seller now reviews age bands on a fixed monthly cadence.
🚧 Common Mistakes to Avoid
❌ Waiting until the charge appears on a report
Sellers often only react once they see the line item. By then the units are already in a tier and are days away from the next assessment. Instead, work from age bands that have not yet triggered a charge — the 121–180 day range is where cheap action is still possible.
⚠️ Discounting the whole catalog instead of the aged units
A blanket price cut feels decisive but erodes margin on products that were selling fine and can reset your pricing expectations with buyers. Apply time-boxed discounts to the specific ASINs and quantities flagged by the age report.
🚫 Removing and re-sending stock to reset the age clock
Pulling units out and shipping them back does start a new age clock, but you pay removal fees, outbound and inbound freight, and any prep costs, and the product still is not selling. Fix the demand problem or exit the units.
❗ Treating disposal as the free option
Disposal and liquidation both carry per-unit fees, and liquidation returns only a fraction of retail value. Run the comparison in step 6 rather than assuming disposal is the cheapest exit.
📊 Expected Results
Applying this process consistently should produce changes you can verify in Seller Central rather than infer:
- Aged unit count in the Inventory Age report declines, and fewer ASINs cross into a new age band each month.
- Storage and surcharge lines on your monthly FBA fee reporting stop growing month over month — expect this to show up on the next full fee cycle, not immediately.
- Sell-through rate improves as excess quantity leaves the network, which typically registers over several weeks rather than days.
- IPI trends upward, reducing the risk of storage restrictions at the 400 threshold.
- Storage-type capacity is reallocated toward products that turn, improving in-stock rates on your best sellers.
None of this is guaranteed — outcomes depend on your category, pricing latitude, and how deep the aged position already is. What is reliable is that acting in the 121–180 day window costs less than acting after the surcharge has begun.
❓ FAQs
🕒 When does the aged inventory surcharge start applying?
The first tier begins at 181 days in a fulfillment center, then escalates through 271–365 days, 12–15 months, and 15+ months. Rates vary by size and are published in Amazon’s FBA fee schedule, so confirm the current figures there before modeling a decision.
📦 Does selling some units lower the age of the rest?
Amazon ages units first-in, first-out, so your oldest units are consumed first as sales occur. Selling reduces how many aged units remain, but sending in new stock does not lower the age of units already there.
🚚 Does the surcharge apply to FBM inventory?
No. Storage fees and the aged inventory surcharge apply to units held in Amazon fulfillment centers. Stock you hold and ship yourself is not subject to them, though it still ties up your own working capital.
📉 Will clearing aged stock fix a low IPI on its own?
It helps, because excess and aged inventory weigh on the score, but IPI also reflects factors such as sell-through and how much of your listed FBA inventory is actually sellable. Clearing dead units and keeping in-stock rates healthy on your movers work together.
🔁 Should I liquidate or remove units to my own address?
Remove to your own address when you have a viable second channel or can rework and resend the product profitably. Choose liquidation when handling the units yourself would cost more than the recovery is worth. Compare the per-unit fees for each option in Amazon’s fee schedule and use net recovery per unit as the deciding number.