Inventory accounting explained: methods, costs, and tax

Published Wednesday 27 May 2026

Table of contents

• What is inventory?
• What isn't inventory?
• What is inventory accounting?
• Why inventory accounting matters
• Inventory accounting methods
• Periodic vs. perpetual inventory systems
• How to do inventory accounting
• Common inventory accounting formulas
• Inventory shrinkage and write-offs
• Benefits of inventory accounting
• Simplify your inventory accounting with Xero
• FAQs on inventory accounting

Key takeaways

• Inventory accounting is the process of tracking, valuing, and recording the cost of goods your business holds for sale, and it directly affects your reported profit, tax obligations, and cash flow.
• Most Canadian small businesses use FIFO or weighted average costing because LIFO isn't permitted under Canadian accounting standards, and your choice of method shapes both your financial statements and your tax return.
• Accurate inventory records help you set profitable prices, satisfy Canada Revenue Agency (CRA) requirements, secure financing, and spot slow-moving stock before it ties up cash.
• Cloud-based accounting tools can automate much of the tracking, so you spend less time on manual record-keeping and more time running your business.

What is inventory?

Inventory is the collection of goods your business has purchased or produced with the intention of selling to customers. These items may be resold as they are, or combined into a new product before sale.

For a retailer, inventory might include clothing on the shelves. For a manufacturer, it could be raw materials, partially assembled products, and finished goods ready to ship. Regardless of your business type, if you hold items that you plan to sell, those items are your inventory.

What isn't inventory?

Not everything your business buys qualifies as inventory. Understanding the difference helps you categorize expenses correctly and avoid errors on your financial statements.

• Business equipment and supplies: Tools, vehicles, computers, and office stationery are recorded as expenses or fixed assets, not inventory.
• Dropshipped goods: If a third party ships products directly to your customer, you never hold the stock, so it isn't your inventory.
• Items you don't own: Consignment goods sitting in your shop belong to the consignor until sold. They don't appear on your balance sheet as inventory.

What is inventory accounting?

Inventory accounting is the process of tracking, valuing, and recording the cost of goods your business holds for sale. It tells you exactly what your stock is worth and what it costs to maintain at any point in time.

Inventory appears as a current asset on your balance sheet (you can learn more about the accounting equation to see how assets, liabilities, and equity connect). However, that value can drop quickly if items become outdated, damaged, or market prices fall. Proper inventory accounting helps you set accurate prices, calculate taxes, secure insurance, and identify your most profitable products.

Inventory as an asset vs. an expense

Inventory is classified as a current asset, not an expense, because it holds value your business can convert to cash through sales. The accounting treatment changes depending on what happens to the stock.

• When you purchase inventory: It goes on your balance sheet as a current asset.
• When you sell inventory: The cost moves to your income statement as an expense called cost of goods sold.
• Unsold inventory: It remains on your balance sheet until it's sold, written off, or adjusted.

This distinction matters for your financial statements. Assets show what your business owns, while expenses reduce your profit. Misclassifying inventory can distort both your balance sheet and your reported earnings.

Why inventory accounting matters

Inventory accounting gives you the financial visibility you need to run a product-based business confidently. Without it, you're guessing at profitability and risking compliance problems.

For many product-based businesses, inventory and materials represent one of the largest and fastest-growing expenses. When those costs are climbing, accurate accounting becomes even more critical for protecting margins and making informed purchasing decisions.

Here's why inventory accounting deserves your attention:

• Tax compliance: The CRA requires accurate inventory records to calculate taxable income. Canada's Income Tax Act stipulates that inventory must be valued at cost or fair market value, whichever is lower.
• Financial reporting: Lenders and investors expect proper inventory valuation on your balance sheet before extending credit or funding.
• Informed pricing: You can't set profitable prices without knowing your true product costs.
• Business valuation: If you ever sell your business, buyers will scrutinize your inventory records closely.
• Cash flow visibility: Understanding what's tied up in stock helps you manage working capital and avoid cash crunches.

Skipping proper inventory accounting may save time in the short term, but it creates bigger problems when tax season arrives or when you need financing.

Inventory accounting methods

The inventory accounting method you choose determines how you calculate the value of stock on hand and the cost of goods sold. Each method affects your reported profit and tax obligations differently.

Here are the four main approaches:

• FIFO (first in, first out): Assumes you sell your oldest inventory first. This method works well when prices are rising because it results in lower cost of goods sold and higher reported profit.
• LIFO (last in, first out): Assumes you sell your newest inventory first. LIFO isn't permitted under the accounting standards that apply in Canada, including IFRS (International Financial Reporting Standards) and ASPE (Accounting Standards for Private Enterprises). It's only allowed under US GAAP (Generally Accepted Accounting Principles).
• Weighted average: Calculates an average cost across all units in stock. It's useful when your inventory items are similar and prices fluctuate moderately.
• Specific identification: Tracks the actual cost of each individual item. This method is best suited for businesses selling unique or high-value products, such as vehicles or custom furniture.

Most Canadian small businesses use FIFO or weighted average. Your accountant can help you choose the method that fits your business and complies with Canadian accounting standards.

Periodic vs. perpetual inventory systems

An inventory system is the framework you use to track when and how inventory quantities and costs are updated. The two main options are periodic and perpetual, and the right choice depends on your business size and complexity.

A periodic system updates inventory records at set intervals, such as monthly or quarterly. You physically count your stock at the end of each period and then calculate cost of goods sold using the formula: beginning inventory plus purchases minus ending inventory. This approach is simpler to maintain but gives you less real-time visibility into what you have on hand.

A perpetual system updates inventory records continuously as each purchase and sale occurs. Every transaction adjusts your stock levels and cost figures automatically. This method gives you an up-to-date picture of inventory at any moment, which is especially helpful if you sell across multiple channels.

For small businesses with a limited product range, a periodic system may be enough. As your product catalogue grows or you start selling online, a perpetual system supported by inventory management software can save you significant time and reduce counting errors.

How to do inventory accounting

Doing inventory accounting well means tracking three things: how much inventory you have, what you're spending on it, and what you're selling it for. The level of detail depends on your business needs and the methods you choose.

1. What costs to include in inventory

When valuing inventory, include all costs required to get items ready for sale. The CRA expects you to account for more than just the purchase price.

• Purchase price: The amount you pay suppliers for goods.
• Shipping and freight: Delivery costs to bring inventory to your location.
• Import duties: Tariffs or customs fees on imported goods.
• Direct labour: For manufacturers, the cost of workers who produce the goods.

Don't include general business expenses like rent, utilities, or administrative salaries. These are operating costs, not inventory costs.

2. How to record inventory in accounting

Recording inventory involves tracking purchases, sales, and adjustments in your books. Here's the basic sequence.

1. When you buy inventory, record it as an asset on your balance sheet.
2. When you sell inventory, record the sale as revenue and move the cost to your income statement as cost of goods sold.
3. When you count inventory, adjust your records to match physical counts, accounting for shrinkage, damage, or obsolescence.

Cloud-based accounting software like Xero can automate much of this process, updating your records as transactions occur and reducing manual data entry.

3. Cost of goods sold and inventory

Cost of goods sold represents the direct cost of producing or purchasing the items you've sold during a period. It's one of the most important figures on your income statement because it directly affects your gross profit.

The basic COGS formula is: beginning inventory + purchases − ending inventory = COGS.

Tracking COGS accurately matters because it shapes your reported profit. If COGS is overstated, your margins look thinner than they are. If it's understated, you may overestimate profitability and make poor purchasing decisions. You can read more about inventory and cost of goods sold on the CRA website.

Common inventory accounting formulas

A handful of formulas form the backbone of inventory accounting. Knowing them helps you calculate stock values, measure efficiency, and spot problems before they affect your bottom line.

• Beginning inventory: This is the value of stock on hand at the start of an accounting period. It equals the ending inventory from the previous period. If your last quarter ended with $20,000 in inventory, that's your beginning inventory for the current quarter.
• Ending inventory: This is the value of stock remaining at the end of a period. You can calculate it as: beginning inventory + purchases − cost of goods sold = ending inventory. Using the example above, if you started with $20,000, purchased $15,000, and your COGS was $18,000, your ending inventory would be $17,000.
• Inventory turnover ratio: This measures how many times you sell through your inventory in a given period. The formula is: cost of goods sold ÷ average inventory = inventory turnover ratio. A higher ratio generally means you're selling stock efficiently, while a low ratio may signal overstocking or slow-moving products.

Here's a worked example of the COGS formula. Suppose you run a small retail shop. You start the month with $10,000 in inventory, purchase an additional $6,000 of stock, and end the month with $8,000 of unsold goods.

Your COGS for the month is: $10,000 + $6,000 − $8,000 = $8,000. That $8,000 goes on your income statement as the cost of the products you sold.

Inventory shrinkage and write-offs

Inventory shrinkage is the difference between the stock your records say you have and the stock you actually have on hand. It's a common issue for product-based businesses, and ignoring it can quietly erode your profits.

Shrinkage typically results from theft, damage, administrative errors, or supplier fraud. The formula to calculate it is: recorded inventory − physical inventory = shrinkage. For example, if your records show $50,000 of inventory but a physical count reveals only $48,500, your shrinkage is $1,500.

When inventory loses its value entirely, whether through damage, expiry, or obsolescence, you'll need to write it off. A write-off removes the item's value from your balance sheet and records it as a loss on your income statement. Smaller adjustments, called write-downs, reduce the recorded value without removing the item entirely.

Regular physical counts help you catch shrinkage early. Comparing your counted stock against your accounting records each quarter, or even monthly, lets you identify patterns and take corrective action before losses add up.

Benefits of inventory accounting

Good inventory accounting does more than keep your books tidy. It gives you actionable information that can directly improve your profitability and cash flow.

• Maximize sales: Keep popular products in stock so you never miss a sale.
• Lower storage costs: Order fewer slow-moving items to reduce warehousing and write-off expenses.
• Negotiate better deals: Identify high-volume items and use that data to secure bulk discounts from suppliers.
• Reveal true profit margins: Track actual stock costs to understand which products make you money and which don't.
• Plan smarter promotions: Spot seasonal trends and time your marketing accordingly.
• Manage tax timing: Control when you place orders to influence your COGS and, in turn, your tax obligations.

Strong inventory accounting also improves your cash flow. When you know exactly what's selling and what's sitting idle, you can free up money that would otherwise be tied up in slow-moving stock. That cash can go toward paying down debt, investing in growth, or covering unexpected expenses.

Simplify your inventory accounting with Xero

Inventory accounting doesn't have to be complicated. When you track your stock accurately, choose the right valuation method, and connect your inventory data to your financial reports, you gain the clarity you need to make confident business decisions.

Inventory accounting software like Xero helps you track what's selling, manage costs, and see your true profitability in real time. With automated bank feeds, built-in reporting, and integrations with tools like Shopify and Stripe, Xero can take much of the manual work out of inventory tracking. Get one month free.

FAQs on inventory accounting

Here are answers to frequently asked questions about inventory accounting.

What are the four types of inventory?

The four main types are raw materials (components used in production), work in progress (partially completed goods), finished goods (products ready for sale), and maintenance, repair, and operations supplies (items that support production but aren't sold directly). For tax purposes, certain professionals such as accountants and lawyers previously had an election to exclude work-in-progress from inventory, but this option was eliminated by the 2017 Federal Budget and fully phased out by the 2022 tax year.

How do you record inventory in accounting?

Record inventory purchases as current assets on your balance sheet. When you sell items, move the cost to your income statement as cost of goods sold and record the sale amount as revenue. Regular physical counts help you adjust for any discrepancies between your records and actual stock.

What's the difference between inventory management and inventory accounting?

Inventory management focuses on the physical side: ordering, storing, and tracking stock levels. Inventory accounting focuses on the financial side: valuing stock, calculating cost of goods sold, and reporting inventory on your financial statements. Both work together to give you full visibility into your business.

How does inventory accounting affect taxes?

Your inventory accounting method directly affects your taxable income. A higher cost of goods sold lowers your reported profit and, in turn, your tax bill. The CRA requires you to value inventory consistently and at the lower of cost or fair market value, so choosing the right method from the start can help you stay compliant and manage your tax obligations effectively.

What's the difference between periodic and perpetual inventory systems?

A periodic system updates inventory records at set intervals through physical counts, while a perpetual system updates records continuously as each transaction occurs. Periodic systems are simpler to maintain but offer less real-time visibility. Perpetual systems, often supported by accounting software, give you an up-to-date picture of stock levels at any moment.

When do I need inventory accounting software?

Consider dedicated software when spreadsheets become hard to maintain, manual tracking leads to errors, or you can't easily see which products are profitable. Cloud-based tools like Xero automate much of the process and connect your inventory data directly to your financial reports, saving you time and reducing mistakes.