Why You Should Be Tracking Every Movement of Your FBA Inventory
I stopped using spreadsheets for my FBA inventory tracking when I realized I was losing money on receipts that never made it into Seller Central. It took about six months of auditing my own shipments before I figured out that the standard way people handle this just doesn't hold up at scale. An Amazon Fba Logbook is basically a structured record of everything you ship into Amazon's fulfillment centers — what you sent, when, how much, and what actually arrived. That's the basic definition. The reason it matters is that Amazon's inbound reporting is notoriously incomplete. You'll send 400 units. Amazon might confirm 387. If you don't have a log, you're working from memory and that's how money disappears. Here's how I set mine up and why it ended up being the single most useful thing in my operation. I use a Google Sheet with columns for shipment ID, ASIN, SKU, units shipped, carrier, tracking number, expected delivery date, units received, discrepancy amount, and resolution status. That's it. No fancy dashboards. No automation layer that breaks every time Amazon changes their API. Just a row per shipment with enough detail to file a claim if something goes wrong. The workflow is straightforward. Every time I create a shipment in Seller Central, I copy the shipment ID and tracking information directly into the sheet within an hour of creation. I never wait until the shipment arrives because by then I've already forgotten the details. When Amazon confirms receipt, which happens somewhere between 3 and 14 days later, I go back to that same row and fill in the received column. Then I run a quick formula to flag any discrepancy greater than zero. If there's a gap, I open a case with Amazon within 18 days because that's the window they give you for inbound claim submissions. Miss that window and the money is gone.
I used to batch this process weekly. That was a mistake. I'd spend four hours on a Sunday trying to piece together what happened across half a dozen shipments while also trying to remember which carrier was which. Switching to the hourly entry habit cut my tracking time down to maybe twenty minutes a week across all my active shipments. The real time savings isn't in the data entry though. It's in not having to chase missing inventory three months later when you're already dealing with a different problem.
The Problem No One Talks About
Here's something I learned the hard way. Amazon's "received" confirmation doesn't always match their actual counted inventory. There's a difference between Amazon saying they got your shipment and Amazon saying they found every single unit inside it. I had a shipment where Amazon confirmed receipt of 320 out of 350 units right away. I marked it as complete in my logbook and moved on. Two weeks later I got an adjustment notification for 12 missing units. But here's the thing — those 12 units weren't actually missing. They were in a pallet that got mislabeled at the receiving dock. Amazon's system showed them as lost because the barcode on the outer box didn't match the shipment records. I spent three weeks and four support cases proving it. The workaround was simple but nobody tells you about it: every time you get a negative adjustment, pull the specific shipment ID from your logbook and compare it against the adjustment report in Seller Central's Business Reports. If the adjustment date falls within 30 days of your shipment's delivery date, file a claim immediately even if Amazon already marked it as resolved. The system auto-closes these cases after 60 days and you lose the ability to dispute it. I filed claims on about three shipments this way and recovered roughly four thousand dollars across two quarters. That's not exceptional. That's average. Most sellers think a logbook is just about tracking individual shipments. It's not. The real value shows up when you start cross-referencing data across multiple dimensions. Here's what I mean. After running my logbook for about eight months, I noticed a pattern in the discrepancies. Shipments going through certain carrier hubs had consistently higher mismatch rates. It wasn't random. Amazon has different processing standards at different fulfillment centers and some centers are stricter about rejecting units with damaged packaging even when the product inside is fine. My logbook let me track which fulfillment centers were causing problems because I could filter by receiving location. Once I identified the problematic centers, I changed my packaging strategy — double-wrapped everything going to those locations and started using more rigid box inserts. The discrepancy rate dropped from about 3.2 percent to under 1 percent. You can't spot that pattern without consistent historical data in a structured format. Another thing that catches people off guard. When you're sending multi-SKU shipments, Amazon sometimes splits a single shipment across multiple fulfillment centers. Your logbook needs to account for that. I learned this when I sent a shipment that got split between two centers. I recorded the full quantity as received at one center and completely missed the other half. The discrepancy showed up as a ghost loss in my numbers for months. The fix was to add a column for split shipment tracking where I note the original quantity and then break it down by destination center as soon as Amazon sends the split notification.
Get the Full Details
Where This Approach Breaks Down
I want to be clear about the limitations because nobody else really does. A manual logbook like this requires discipline. If you're shipping more than four to five units per month, the hourly entry habit becomes a genuine time commitment. I've seen sellers try to automate this with third-party tools that pull directly from Amazon's MCF and FBA APIs. Some of them work well for basic tracking. Most of them break when Amazon updates their API endpoints, which happens roughly twice a year. At that point you're either paying for a tool to fix itself or you're back to manual entry. The hybrid approach I'd recommend is using a tool for the initial data pull and then using your logbook as the source of truth where discrepancies get tracked and resolved. Don't let the tool be your only record. There's also the question of whether a spreadsheet is the right format long-term. When you hit around 200 shipments in your history, searching through rows becomes annoying. At that point I'd recommend migrating to a proper database or a dedicated inventory management platform. But you won't know when you've hit that threshold unless you've been logging everything from day one. So start with the spreadsheet. Upgrade later.
Getting Started With Your Amazon Fba Logbook
If you want a template, the easiest starting point is to create a Google Sheet with the columns I described and lock the header row so it doesn't get accidentally deleted. I don't have a pre-built template to share, but the structure is simple enough that you can have it running in about fifteen minutes. The alternative is spending a few hundred dollars on an inventory management tool that does all of this automatically, but you'll still need a backup log because those tools have the same API failure problem I mentioned. The core habit is what matters, not the tool. Track every shipment the moment you create it. Update it the moment Amazon confirms receipt. Flag every discrepancy and file claims within the 18-day window. Do that consistently and you'll recover money that most sellers just accept as a cost of doing business.
