Inventory Accounting Methods: FIFO, LIFO, and Weighted Average Explained
For Ontario businesses that buy or manufacture products for resale, inventory valuation significantly affects cost of goods sold, gross profit, and taxable income. The method you use to value inventory—FIFO, weighted average, or specific identification—determines which costs flow to your income statement versus balance sheet. At BBS Accounting in Toronto, we help product-based businesses select and implement appropriate inventory methods that comply with CRA requirements while optimizing financial results.
Why Inventory Valuation Matters
Inventory sits on your balance sheet as an asset until sold. When sold, its cost transfers to cost of goods sold on your income statement. The valuation method determines which inventory costs transfer when.
This affects: gross profit (and thus net income), taxable income and taxes owed, inventory value on balance sheet, and financial ratios like current ratio and inventory turnover.
FIFO (First-In, First-Out)
FIFO assumes the oldest inventory sells first, like a grocery store rotating stock—oldest milk sells before newer milk.
How It Works: Purchase 10 units at $5 each (January), purchase 10 units at $6 each (February), sell 12 units in March. Under FIFO, the 12 units sold came from: 10 units at $5 (all January inventory), 2 units at $6 (from February inventory). COGS = (10 × $5) + (2 × $6) = $62. Remaining inventory: 8 units at $6 = $48.
Advantages: Matches physical flow for many businesses, ending inventory reflects recent costs (closer to market value), acceptable to CRA, simple to understand and implement.
Disadvantages: In rising price environments, COGS uses old lower costs while inventory uses recent higher costs, creating higher profits and higher taxes.
Best For: Perishable goods, businesses where physical flow is first-in-first-out, stable or rising price environments, and businesses prioritizing balance sheet accuracy.
At BBS Accounting, FIFO is our most common recommendation for Ontario retail and wholesale businesses.
LIFO (Last-In, First-Out)
LIFO assumes newest inventory sells first. Important: LIFO is generally NOT accepted in Canada for tax purposes, though it can be used for management accounting.
Why It’s Not Used in Canada: CRA requires inventory methods to match physical flow or be systematic and rational. LIFO rarely matches physical flow and can significantly distort income. International Financial Reporting Standards (IFRS) also prohibit LIFO, and Canadian businesses increasingly adopt IFRS.
Limited Application: Some businesses use LIFO internally for pricing decisions but must convert to FIFO or weighted average for financial statements and tax returns.
If a U.S. advisor recommends LIFO, understand it won’t work for Canadian tax purposes. Stick with FIFO or weighted average.
Weighted Average Cost
Weighted average calculates average cost of all inventory units and applies this average to sales and ending inventory.
How It Works: Purchase 10 units at $5 (January) = $50 total, purchase 10 units at $6 (February) = $60 total. Total: 20 units costing $110. Weighted average cost: $110 / 20 = $5.50 per unit. Sell 12 units: COGS = 12 × $5.50 = $66. Remaining inventory: 8 × $5.50 = $44.
After each purchase, recalculate average: (Previous inventory value + New purchase cost) / Total units.
Advantages: Smooths cost fluctuations, simple for businesses with interchangeable goods, reduces impact of timing on profits, acceptable to CRA.
Disadvantages: Doesn’t match physical flow, ending inventory may not reflect current costs, requires recalculation with each purchase (though software handles this automatically).
Best For: Commodities where units are interchangeable, businesses with frequent purchases at varying prices, manufacturers mixing batches, and businesses wanting to smooth earnings.
Many Ontario manufacturers use weighted average because production mixes materials from different purchase batches.
Specific Identification
Specific identification tracks the actual cost of each individual item sold, requiring each unit to be uniquely identifiable.
How It Works: Purchase car #1 for $25,000, car #2 for $26,000, car #3 for $24,000. Sell car #2: COGS = $26,000 (actual cost of that specific car). Remaining inventory: car #1 ($25,000) + car #3 ($24,000) = $49,000.
Requirements: Each item must be uniquely identifiable (serial numbers, VINs, lot numbers), must track which specific item was sold.
Advantages: Matches actual costs to actual sales perfectly, required for certain industries, provides precise information.
Disadvantages: Administrative burden tracking individual items, impractical for large volumes of similar items, opportunity to manipulate profits by choosing which items to sell.
Best For: Vehicle dealers, jewelry stores, art galleries, heavy equipment sales, custom manufacturing, and any business with unique high-value items.
Lower of Cost or Market Rule
Regardless of method chosen, CRA requires inventory to be valued at lower of cost or market value (net realizable value).
What This Means: Calculate inventory at cost using your method (FIFO, weighted average, etc.), determine market value (what you could sell it for minus selling costs), value inventory at the lower of the two amounts.
Example: Inventory cost (FIFO): $50,000. Market value (net realizable value): $45,000. Inventory must be written down to $45,000, with $5,000 loss recognized.
When This Applies: Obsolete inventory (technology, fashion), damaged goods, seasonal items after season ends, excess inventory unlikely to sell at normal prices.
Year-End Review: Assess inventory condition and marketability. Write down any items worth less than cost. This is required, not optional.
At BBS Accounting, we guide clients through year-end inventory valuation ensuring compliance with lower of cost or market rules.
Perpetual vs. Periodic Systems
Perpetual Systems: Update inventory continuously with each sale and purchase. Software tracks inventory in real-time. Know inventory levels and COGS at any moment. Most modern businesses use perpetual systems.
Periodic Systems: Count inventory periodically (monthly, quarterly, annually). Calculate COGS as: Beginning Inventory + Purchases – Ending Inventory. Don’t know exact inventory between counts. Increasingly rare with modern software.
CRA accepts both methods but perpetual systems provide better control and financial visibility.
Physical Inventory Counts
Even with perpetual systems, physical counts are essential. Conduct full physical inventory count at least annually (year-end), investigate variances between physical count and system records, adjust records to match physical reality.
Common Variance Causes: Theft (shoplifting, employee theft), damage or spoilage, counting errors, transaction recording errors (wrong quantities, missed transactions).
Documentation: Record count procedures, identify counters, document adjustments made, investigate significant variances.
Physical counts also satisfy CRA requirements for inventory verification.
Tax Implications
Consistency Requirement: Once you choose a method, you must use it consistently. Changing methods requires CRA approval and specific procedures.
Timing of Income Recognition: FIFO generally results in higher income (and taxes) during rising prices compared to weighted average. Weighted average smooths income recognition over time.
Year-End Purchases: Large year-end purchases affect COGS differently under each method. Under weighted average, a large purchase at high cost immediately increases average cost and COGS on current-year sales. Under FIFO, the purchase sits in ending inventory with no current-year COGS impact.
Strategic Considerations: If prices are rising and you use FIFO, delay year-end purchases to reduce ending inventory and increase COGS (lower income, lower taxes). If using weighted average, timing matters less since purchases affect average cost regardless of when they occur.
At BBS Accounting, we help clients understand tax implications of inventory methods and timing decisions.
Choosing the Right Method
Consider These Factors:
Nature of Goods: Perishable (FIFO), interchangeable commodities (weighted average), unique items (specific identification).
Price Trends: Stable prices (method matters less), rising prices (FIFO = higher profits, weighted average = smoothed profits), falling prices (FIFO = lower profits).
Administrative Capacity: Specific identification requires most effort. FIFO and weighted average work with standard software.
Financial Statement Goals: Wanting higher profits for lending (FIFO in rising price environment), wanting smoother earnings (weighted average), wanting balance sheet accuracy (FIFO).
Industry Norms: What do competitors use? What do lenders expect in your industry?
Most Ontario product businesses use FIFO or weighted average. Specific identification is reserved for unique item businesses.
Software Implementation
Modern accounting software handles inventory methods automatically.
QuickBooks: Supports FIFO and weighted average (called “average cost”). Set method in inventory preferences. Software calculates COGS automatically with each sale.
Xero: Uses weighted average cost by default. Automatically recalculates average with each purchase. No manual calculation needed.
Specialized Inventory Software: More sophisticated systems support multiple methods, lot tracking, serial number tracking, and multi-location inventory.
At BBS Accounting, we configure software with appropriate methods and ensure calculations are working correctly.
Common Mistakes
Inconsistent Application: Using FIFO sometimes and weighted average other times. Choose one method and stick with it.
Ignoring Physical Counts: Relying entirely on system records without verifying physical inventory. Counts are essential for accuracy.
Not Writing Down Obsolete Inventory: Keeping obsolete items at full cost on books. Lower of cost or market requires writedowns.
Changing Methods Without Approval: Switching methods without understanding CRA requirements and properly adjusting.
Poor Documentation: Not documenting count procedures, adjustments, or method selection.
Working with BBS Accounting
We provide comprehensive inventory accounting support:
- Method selection based on your business and goals
- Software configuration for proper inventory tracking
- Year-end physical count procedures
- Lower of cost or market assessments
- Obsolescence review and writedown calculation
- Variance investigation and adjustment
- CRA compliance assurance
Our inventory expertise ensures your inventory is valued correctly, your COGS is accurate, and your financial statements are reliable.
The Bottom Line
Inventory valuation methods significantly impact financial results and taxes. FIFO and weighted average are the primary methods for Canadian businesses, with specific identification for unique items. Choose based on your business nature, price trends, and goals.
Regardless of method, maintain accurate records, conduct physical counts, and apply lower of cost or market rules. Proper inventory accounting is essential for financial accuracy and CRA compliance.
Contact BBS Accounting today to review your inventory methods and procedures. We’ll ensure you’re using the optimal method for your business and that your inventory records meet CRA requirements.