Manufacturing inventory tracking works fundamentally differently from other business expenses. When a service business buys supplies, those go to expenses. When a retailer buys products, those go straight to inventory. But manufacturers transform raw materials into something new, and the accounting has to reflect that transformation process. Treating all purchases as expenses creates financial statements that don’t reflect reality.

You need three separate inventory accounts on your balance sheet. Raw materials holds everything you’ve purchased but haven’t started using in production. This includes steel, chemicals, packaging materials, components from suppliers, and whatever else goes into your products. These purchases don’t hit your income statement as expenses when you buy them. They sit as assets until you start using them.

Work in process captures products currently being manufactured. When raw materials move to the production floor, you transfer their cost from raw materials to WIP. But WIP isn’t just materials. You add direct labor for wages paid to employees actually making the product. You also add manufacturing overhead like factory rent, equipment depreciation, utilities for the production facility, and indirect labor such as supervisors. All of this accumulates in WIP as the product moves through production stages.

Finished goods holds completed products ready for sale. When production completes, you transfer the full accumulated cost from WIP to finished goods. The product now sits on your balance sheet at its full manufacturing cost until a customer buys it.

Cost of goods sold only gets recognized when you sell a finished product. That’s when the cost leaves your balance sheet and hits your income statement. This timing matters for business tax preparation and for understanding actual profitability. If you expense everything when you buy it, you show losses in months when you’re building inventory and profits in months when you’re selling from existing stock. Neither reflects actual production efficiency or business performance.

Labor allocation deserves specific attention. Direct labor hours worked on specific products should attach to those products in WIP. Indirect labor and overhead typically get applied using an allocation rate based on labor hours or machine hours. This spreads costs across production in a way that reflects actual resource usage.

Tracking this correctly requires systems that follow physical inventory movement. When materials get pulled for a production run, that transaction records in your books. When production workers log hours, that labor gets allocated to the products they worked on. When a run completes, the transfer to finished goods gets documented. When products ship, COGS gets recorded against the sale.

The common mistake is expensing material purchases when you buy them. This makes your profit margins meaningless because they don’t reflect what products actually cost to make. You can’t price products correctly or evaluate whether production changes are working if your numbers don’t track manufacturing costs accurately.

Inventory accounting for manufacturers requires software configured with the proper account structure and transaction workflows. Getting this set up correctly from the start prevents messy cleanup work later and gives you financial statements that actually help you run the business. Physical inventory counts need to reconcile with your books, and any variances need investigation. The goal is numbers you can trust when making production and pricing decisions.