How to Track Inventory for Amazon FBA Sellers

You sent 5,000 units of your best-selling kitchen gadget to Amazon. Two weeks later, you check your seller dashboard and see a red alert: "Inbound Performance — Excessive stock received." Your storage fees just jumped, and your IPI (Inventory Performance Index) score is dropping.

Meanwhile, your other SKU is out of stock and you're losing the Buy Box to a competitor.

This is the daily reality for Amazon FBA sellers who don't have a solid inventory tracking system.

The Problem: Why FBA Inventory Tracking Is So Hard

Unlike traditional retail, Amazon FBA creates a unique inventory challenge. You're managing stock across three distinct phases:

1. Your warehouse — raw materials or finished goods before shipment
2. In transit — inventory on its way to Amazon fulfillment centers
3. Amazon's network — stock sitting in FCs (Fulfillment Centers) across the country

And each phase has different rules, fees, and visibility.

The Real Costs of Poor Tracking

Problem	Monthly Impact (approx.)
Stockouts of top 10% SKUs	Lose $2,000–$15,000 in revenue per SKU
Excess inventory (90+ days)	$0.15–$0.50 per cubic foot per month + Long-Term Storage Fees
IPI score below 400	Storage limits imposed; can't send more inventory
Lost Buy Box due to stockouts	60–80% drop in sales for that ASIN

Amazon sellers commonly report excess storage fees and stockouts as their top inventory pain points. According to industry data, the average seller loses significant revenue from stockouts of their best-selling products, while excess inventory quietly erodes margins through storage fees.

Root Cause: You're Flying Blind

The core issue isn't that you're bad at inventory management. It's that most sellers rely on disconnected tools:

• Amazon Seller Central for FBA stock levels
• A spreadsheet for your own warehouse
• Email or WhatsApp for supplier orders
• Manual counts that happen once a month

This fragmentation leads to three fatal mistakes:

1. Over-shipping to Amazon because you can't see what's already there
2. Under-ordering from suppliers because your lead time data is stale
3. Dead stock accumulation because you never flagged slow movers

The Solution: A 4-Step Tracking System That Works

Here's a practical framework you can implement this week. No expensive software required — though a dedicated tool makes it far easier.

Step 1: Unify Your Inventory View

Stop juggling three systems. Create a single source of truth that shows:

• On-hand quantity (in your facility)
• Inbound to Amazon (in transit)
• Fulfillable quantity (at Amazon FCs)
• Reserved quantity (customer orders not yet shipped)
• Inbound from supplier (on order)

How: Export your Amazon inventory report daily (Reports > Fulfillment > Daily Inventory History). Combine it with your local stock count in a Google Sheet or dedicated inventory management tool.

Step 2: Set Reorder Points Based on Lead Time + Safety Stock

Don't guess when to reorder. Calculate it:

Reorder Point = (Average Daily Sales × Lead Time in Days) + Safety Stock

Example for a product selling 50 units/day with 14-day lead time:

• Reorder point = (50 × 14) + 200 (safety stock) = 900 units
• When your total inventory (local + FBA) hits 900, place your next order

Pro tip: Amazon's Restock Inventory report shows your "sell-through rate" per ASIN. Use the 90-day average daily sales — not just the last 30 days — to account for seasonality.

Step 3: Implement Cycle Counting — Not Annual Counts

Physical inventory counts once a year are useless for FBA. Switch to cycle counting: count a small subset of SKUs every week.

Priority	SKU Category	Count Frequency
A	Top 20% of SKUs (80% of revenue)	Weekly
B	Middle 30% of SKUs	Bi-weekly
C	Bottom 50% of SKUs	Monthly

This catches discrepancies early — before they snowball into IPI penalties or stockouts.

Step 4: Automate Alerts for Critical Thresholds

Set up notifications for:

• Low stock alert: Total inventory falls below 30 days of cover
• Excess stock alert: Inventory age exceeds 60 days at Amazon
• IPI score drop: Alert when score falls below 450
• Receiving discrepancy: Amazon receives fewer units than you shipped

How Fluxventory Helps Amazon FBA Sellers

Fluxventory was built for sellers who manage inventory across multiple locations — including Amazon FBA. Instead of logging into Seller Central for FBA stock, a spreadsheet for your warehouse, and email threads for supplier orders, you get one unified dashboard.

The platform automatically syncs with your Amazon seller account to pull real-time FBA inventory data, then combines it with your local stock and incoming purchase orders. You can set custom reorder points, receive low-stock alerts via email or mobile push, and even scan barcodes with your phone to reconcile shipments before they leave your facility.

It's designed for SMBs that don't have a dedicated inventory manager — the same businesses that can't afford enterprise tools like Cin7 or Fishbowl but still need professional-grade tracking.

For more inventory management strategies, check out our guide on multi-location inventory tracking and our barcode scanning best practices.

Conclusion: Stop Reacting. Start Predicting.

Inventory tracking for Amazon FBA doesn't have to be a constant firefight. When you have a system that shows you one unified view of your stock — from supplier to Amazon FC to customer — you can make decisions with confidence.

You'll know exactly when to reorder, how much to send to Amazon, and which SKUs to liquidate before they eat into your profit with storage fees.

The sellers who win on Amazon aren't the ones with the best products. They're the ones who never run out of stock and never overpay in storage fees.

Ready to get your inventory under control? Start your free trial at Fluxventory and see your complete inventory picture in under 10 minutes. No credit card required.

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About the Author: The Fluxventory Team helps small and medium businesses streamline their inventory operations with modern, mobile-first tools. We write about inventory management best practices, Amazon FBA strategies, and operations optimization for growing businesses. Learn more about Fluxventory.