What is an FBA inventory discrepancy?
An FBA inventory discrepancy is any gap between the units you shipped to Amazon and the units Amazon's reports show. The four most common forms are missing units (shipped but not received), unfulfillable units (received but graded unsellable), damaged units (received but damaged in FC), and removal/disposal discrepancies (asked to remove or dispose, but the count does not match).
Discrepancies happen for a wide range of reasons — receiving errors, warehouse transfers between FCs, customer returns, removal / disposal errors, and shrink. Most sellers catch a portion of the discrepancies on a monthly reconciliation cycle, but a meaningful share of lost units are only visible when you cross-reference multiple reports.
How to use this calculator
- Open Seller Central › Reports › Fulfillment and pull the Shipment Detail report for the shipment you are reconciling.
- Enter your units shipped and units received.
- Enter your current available, reserved, damaged, unfulfillable, and removed / disposed counts. The Inventory Event Detail report is the source of truth.
- Enter reimbursed units so far so the calculator does not double-count Amazon's existing credits.
- Enter your average COGS, selling price, and FBA fee per unit to size the dollar impact.
- Pick the shipment creation date and reconciliation date. The calculator flags the 18-month claim window.
- Read the missing unit count, profit impact, and possible reimbursement range. Use the Amazon Reimbursement Calculator for category-level recovery sizing.
How missing units are calculated
The calculator uses a reconciliation identity:
Expected on-hand = Shipped − already known losses
Where the "known losses" are the cumulative inventory changes Amazon has recorded — sold units, removed units, customer returns not restocked, etc. If your entered available + reserved + damaged + unfulfillable + removed sum is less than expected on-hand, the gap is the estimated missing units.
For a simpler shipped-vs-received check, the calculator also surfaces the receiving gap. If shipped is 2,000 and received is 1,950, the receiving gap is 50 units. That is the most common place to start a claim.
How the reimbursement range is calculated
The possible reimbursement range is built from three layers:
- COGS-only floor: Amazon typically reimburses at your cost basis for lost or damaged units. The lower bound uses missing units × COGS.
- Sales value ceiling: For specific dispute categories (lost inbound with proof of value, customer-return discrepancies with order ID), Amazon may credit the sale value. The upper bound uses missing units × selling price.
- Profit impact midpoint: The midpoint uses missing units × (selling price − COGS − FBA fee), which is the contribution margin you would have earned if the unit had sold normally.
Actual reimbursement can land anywhere in this range depending on evidence, claim category, and Amazon's review.
What is included in the estimate
- Reconciliation identity: shipped − received, and expected − observed on-hand.
- COGS loss, sales value lost, and profit impact using your per-unit math.
- Possible reimbursement range with a COGS floor and a sales value ceiling.
- Claim window countdown using the 18-month Amazon guideline.
- Reports list tied to each discrepancy type.
What is not included
- Long-tail or aged-out events that have already passed the 18-month window. The calculator surfaces this as a status flag — it does not pretend the events are still claimable.
- Lost Buy Box revenue, suppressed-listing losses, or stranded-inventory exposure. See the Suppressed Listing Loss Calculator and the Stranded Inventory Cost Calculator.
- Carrier or freight insurance recoveries. Those are handled by your carrier, not Amazon.
- Cost of using a third-party reimbursement service (typically 15–25% of recovered amount). Amazon's Seller Central case flow is free.
Example scenario: 2,000 shipped, 1,950 received, 50 units unaccounted for
Example scenario, not a customer case study. A seller ships 2,000 units of a $30 / $9-COGS / $5.24-FBA-fee SKU to a single FC. After 30 days the FC reports 1,950 received, 1,850 available, 40 reserved, 20 damaged, 30 unfulfillable, 10 removed. No prior reimbursements.
Receiving gap: 2,000 − 1,950 = 50 units not received
On-hand sum: 1,850 + 40 + 20 + 30 + 10 = 1,950 (matches received — no internal shrink detected)
Estimated missing units: 50 (all on the receiving side)
COGS loss: 50 × $9 = $450
Sales value lost (if claimed at sale value): 50 × $30 = $1,500
Profit impact midpoint: 50 × ($30 − $9 − $5.24) = $788
Possible reimbursement range: $450 – $1,500 (COGS floor to sales value ceiling)
Frequently Asked Questions
What is an FBA inventory discrepancy?
An FBA inventory discrepancy is any gap between the units you shipped to Amazon and the units Amazon's reports show. The four most common forms are missing units, unfulfillable units, damaged units, and removal / disposal discrepancies.
How do I reconcile FBA inventory?
Open Seller Central › Reports › Fulfillment and pull the Inventory Event Detail, Adjustments, Removal Order Detail, and Returns reports. Sum the changes during the reconciliation window and compare to your shipment log. Any gap is a discrepancy.
How long do I have to file an FBA inventory discrepancy claim?
Amazon's published guidance is that FBA inventory issues can be reported within 18 months of the event for most categories. Filing inside the window does not guarantee reimbursement — Amazon reviews each case individually.
What reports should I check?
Pull the Inventory Event Detail report (the source of truth for all inventory changes), the Adjustments report, the Removal Order Detail report, the Returns report, and the Reimbursements report. Cross-check expected vs received units, expected vs reimbursed units, and any open shipments with no receiving scan.
Does this calculator guarantee reimbursement?
No. This is a planning estimator that converts your shipped vs received vs available counts into a missing-unit estimate and a COGS / sales-value / profit impact range. Actual reimbursement depends on Amazon's review of each case, your evidence, claim timing, and category-specific eligibility.
What if the receiving report shows 0?
Leave the units received field at 0. The calculator will treat the entire shipment as the missing-unit estimate and the claim urgency as elevated. The Inventory Event Detail report usually has receiving scans within 5–10 business days; if you are at 30+ days with no receiving scan, open a shipment-issue case immediately.