Mastering inventory tracking with fulfillment reports alone?

Hey there,
is anyone here manually tracking their stock at Amazon’s fulfillment centers?
Meaning, to figure out the exact number of units Amazon has on hand by the end of each month (in any status/disposition) and to also watch for any missing units or discrepancies with the inventory we’ve sent to the fulfillment centers.

To me, it feels impossible, but I am far from special so I’m really looking forward to hearing your thoughts on this.

I started by merging two inventory reports: Manage FBA Inventory and Restock Inventory. (they overlap a bit)
Basically, I pull these reports early in the morning on the 1st of each month and then I aggregate them using a pivot table so I can see Available, FC Transfer/Processing, Reserved Customer Order, Unfulfillable, Researching, and Inbound Working/Shipped/Receiving.
Then I have to compare those data with shipped sold units, as well as returned units.

Unfortunately, this report alone is not sufficient, as it does not provide data on all the lost units and the disposed ones.

The second limitation is that, even if some units still show as ‘Inbound Receiving,’ they may have already been sold and shipped to customers (I can tell this because in some instances, the sum of Units Sold, Reserved, and Available is already close to the total number I have shipped to the fulfillment center. Adding the number currently shown as ‘Inbound’ would cause the total amount to exceed the number of units shipped to the FC’s).

For sure we could make some sort of comparison by using the inventory ledger… but… what a challenge.

It appears that the ending quantity can be calculated as explained by Amazon (ending warehouse balance + in transit between warehouses).
However, it is not immediately apparent how to calculate the number of units that were damaged over a certain period of time, while also being able to determine if they have been disposed of or if they have become sellable again (in fact, another issue I’ve encountered here is that I was hoping I could simply sum the ‘Damaged’ column to know how many units got damaged in a given period. The problem is that we can also get a damaged disposition from units under the ‘Found’ column. So you never see that unit under the ‘Damaged’ column, but it is showing as damaged in a row with that disposition. Additionally, in my particular case, I had a unit that was damaged for weeks until one day when it went (-)Negative under ‘Other Events’ to immediately become ‘Sellable’ after becoming (+)Positive under the same ‘Other Events’ column).
I am talking about the Summary View.

Is there a way to manipulate the ‘Damaged,’ ‘Disposed,’ ‘Other Events,’ and ‘Unknown Events’ in such a way as to determine how many units have actually been disposed of and how many are damaged?

Does it make sense to calculate the lost units that are still missing at the end of the month using the following formula: (-/+)Shipments + (-)Lost + (+)Found?"

Is there a proven way to achieve this objective accurately?

Not even Amazon has this nailed down yet. My advice to you is to run one set of reports / calculations annually that calculates this:

  • What you shipped to FBA - What you sold - what’s accounted for using all known ways of getting this data from Amazon’s reports.

If there’s a difference, it’s written off at cost value on April 15th.

This will save you time and you will have the evidence in the case of an audit (won’t be big enough to trigger this).

We’ve been doing this for years. Here are our last 4 years as a percentage of unit loss at FBA:

2019 - .06%
2020 - .04%
2021 - .05%
2022 - .03%

FBA actually does a great job for us in this regard. A 4 year average of 99.95% accuracy.

You will drive yourself insane trying to figure out what’s happening at any given time. Draw a line in the sand, (EOY), do what every large business does, and use the power / benefit of the write off to get back your legitimate loss caused by your 3PL, which in this case is FBA.


Thanks a lot ASV_Vites! I appreciate your advice.
And yes, it would be insanity.

May i ask you if you do anything on a monthly basis to record your inventory levels or any adjustments?

Do you use any specific software for inventory?

This is very impressive. Yet rare, I believe :sweat_smile:

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Other than just watching for shipment receipts to ensure they are in line, no.

Nope, just Quickbooks for our accountant. The firm only cares about what our count is at years end though but we track our internal inventory internally of course…

Initially, we were obsessed with trying to track inventory because of everything we were reading on various forums. Now that those fears have been unfounded (at least for us), we keep it simple.

I suppose if we were selling grand pianos on Amazon, things would be different but our COGS are very low so it really isn’t worth the time or aggravation to get overly ■■■■ about it.

Not sure why the word a n al is censored here but that’s the missing word above. I mean, I know why it’s censored in theory, but we are all adults here.


No, because Amazon’s receiving/transfer of inventory drags way beyond a 30 day window.

In our experience, all attempts to manage Amazon inventory at a micro level are a waste of personnel resources. We push nearly everything out to quarterly to get accurate pictures of inventory movement/loss/etc.

Not rare. We average over 99% accuracy, post receipt of inventory.
It all boils down to if you have a product packaged/designed for Amazons material handling systems.
We have invested tens of thousands of dollars into packaging equipment and printing to ensure our products flow smoothly within the FBA system. We scrutinize each and every bar code and box/bag before we send our first item in.