QuickBooks Online (QBO) makes it easy to keep a real‑time picture of what you have on hand and how much it’s worth. By using the built‑in FIFO (first‑in, first‑out) engine, you can let the system automatically assign the correct cost to each sale, while still having the tools to correct shrinkage, spoilage, or counting errors. The following guide walks through the core concepts, the workflow you should follow, and the common pitfalls to avoid.
Inventory vs Non‑Inventory
- Tracked inventory items – These are items whose quantity on hand (QOH) and balance‑sheet value are recorded in QBO. Every purchase adds to an inventory asset account; every sale reduces QOH and moves the cost into Cost of Goods Sold (COGS).
- Non‑inventory items – These are treated as expenses the moment you purchase them. Use this type for drop‑shipped goods, office supplies, or any item you never store. The cost is posted directly to an expense account, bypassing the inventory asset.
Choosing the right item type prevents unnecessary complexity and keeps your balance sheet clean.
Automated FIFO Costing
QBO applies FIFO automatically: the oldest purchase cost is the first to be recognized as COGS when you sell a unit. The typical flow looks like this:
- Purchase Order (PO) – Create a PO to reserve the quantity you intend to buy.
- Bill – When the vendor invoice arrives, enter a bill. QBO posts the amount to the inventory asset account and updates QOH.
- Sales Invoice – Create an invoice for the customer. QBO pulls the cost from the earliest available purchase layer and records it in COGS, while reducing QOH.
Because the costing is automatic, you don’t need to manually calculate unit costs for each sale; the system ensures that the oldest cost layer is consumed first.
Inventory Adjustments
Real‑world inventory rarely matches the system perfectly. Use the Quantity Adjustment screen whenever you discover:
- Shrinkage (theft or loss)
- Spoilage or damage
- Count errors discovered during a physical count
When you submit an adjustment, QBO debits an Inventory Shrinkage expense account and credits the inventory asset account, keeping the balance sheet accurate without affecting COGS retroactively.
The Negative Inventory Bug
A common error occurs when a sales invoice is entered before the corresponding purchase bill. QBO will allow the sale, driving QOH into negative territory. Later, when you finally record the bill, QBO retroactively re‑costs the earlier sale using the newly entered purchase price. This creates two problems:
- Fatal ledger error – Negative QOH is a red flag and can cause downstream reports to misbehave.
- Distorted historical COGS – The system rewrites the cost of the earlier sale, making your profit margins appear inconsistent.
Avoid this scenario by always entering vendor bills first.
Do / Avoid
Do
- Conduct quarterly physical counts and post any discrepancies through the Quantity Adjustment screen.
- Enter vendor purchase bills before issuing customer sales invoices to maintain correct FIFO costing.
- Use non‑inventory item types for custom‑order, drop‑shipped, or low‑value items that you never store.
Avoid
- Letting inventory quantities drop below zero; it signals a timing issue in the purchase‑sale cycle.
- Adjusting inventory asset balances with manual journal entries; always use the built‑in adjustment feature.
- Tracking low‑cost office supplies or packaging materials as inventory; treat them as expenses.
Keep the flow of purchases → bills → sales consistent, and let QBO handle FIFO costing while you focus on accurate counts and timely adjustments.
Accurate inventory tracking + automated FIFO = reliable financials.
Top comments (1)
The negative inventory point is the one that stuck with me. It is such an easy timing mistake to make when you are busy — invoice the customer first, enter the vendor bill later — and then the margins look wrong for reasons that are hard to trace back. Entering bills first and doing a real quarterly count feels like boring discipline, but it is exactly what keeps the financials trustworthy when prices are moving.