QuickBooks Online uses the FIFO method (First In, First Out) for inventory costing. When you sell a product, QBO assumes you’re selling the oldest units first and calculates your cost of goods sold based on what those units actually cost. You don’t get to choose LIFO or weighted average in QBO, so it’s worth understanding how FIFO affects your reported margins if your purchase prices fluctuate.

Start by enabling inventory tracking. Go to Settings, then Account and Settings, then Sales, and turn on “Track inventory quantity on hand.” Once enabled, create inventory items under Products and Services. For each item, enter the product name, the cost you pay, and the price you sell it for. QBO will create the Inventory Asset and Cost of Goods Sold accounts automatically if they don’t already exist.

When you purchase inventory, record it through a bill or expense and select the inventory item. QBO adds the quantity to your on-hand count and records the cost. When you create an invoice or sales receipt for that item, QBO reduces inventory and moves the appropriate cost from your Inventory Asset account to Cost of Goods Sold. This happens automatically as long as your items are set up correctly.

Run physical inventory counts regularly and compare them to what QBO shows on hand. Discrepancies happen from theft, damage, miscounts, or data entry errors. Use the Inventory Quantity Adjustment feature to correct the numbers when your physical count doesn’t match the system. Every adjustment hits your financials, so document the reason.

A few common mistakes to watch for. Don’t record inventory purchases as regular expenses because that skips the inventory asset entirely and makes your cost of goods sold wrong. Don’t forget to record adjustments for damaged or returned goods. And don’t let months go by without reconciling what’s on the shelf to what’s in the system.

QBO works well for businesses with straightforward inventory needs. If you buy finished goods and resell them with a manageable number of SKUs, the built-in features are probably enough. Where QBO starts to struggle is with manufacturing, assemblies, multiple warehouse locations, or businesses needing lot tracking and serial numbers. In those cases, an add-on like SOS Inventory or Katana can integrate with QBO and handle the complexity.

Working with a QuickBooks ProAdvisor in Chandler helps you get the chart of accounts and inventory items configured correctly from the start. A bad setup means your cost of goods sold, gross margins, and inventory valuations will be off on every financial statement you pull.

For businesses where inventory makes up a significant portion of your assets, accurate inventory accounting affects everything from your tax return to your purchasing decisions. If the numbers in QBO don’t match what’s actually sitting on your shelves, the reports you’re relying on are giving you bad information and you won’t know it until something goes wrong.