FIFO vs LIFO Inventory Accounting Explained
Accounting cost flow assumptions—FIFO, LIFO, and average cost—how they affect COGS and tax, and how they differ from warehouse FEFO rotation on the floor.
Last updated: May 2026
FIFO and LIFO are accounting methods that decide which purchase costs flow to cost of goods sold when you sell inventory—not necessarily the order cartons leave the warehouse. When prices rise, FIFO usually lowers COGS and raises ending inventory value; LIFO does the opposite, which can defer tax in the US but is disallowed under IFRS.
Operations teams often conflate accounting FIFO with physical picking rules. Warehouse rotation may follow FEFO vs FIFO for expiry compliance while finance applies FIFO cost layers in the ledger. Keeping that distinction clear prevents arguments between warehouse and accounting during audits.
Perpetual systems track layers on every receipt and sale—see perpetual vs periodic inventory systems. Turnover and margin analysis connect to what's a good inventory turnover ratio and count accuracy in cycle counting and inventory accuracy. Navigation: inventory hub, guides index, compare inventory software.
Costing support varies: Cin7, Zoho Inventory, and inFlow handle FIFO or average cost at different depths—confirm LIFO needs with your CPA before selection. Reviews: best inventory software.
FIFO in Accounting
Oldest costs to COGS first.
Under FIFO, the first units purchased are assumed sold first. In inflationary markets COGS reflects older, lower costs—gross margin looks stronger and ending inventory on the balance sheet carries newer prices. Auditors expect receipt documentation that supports layer chronology.
FIFO aligns naturally with many physical flows and is the default recommendation for international reporting. Pair with barcode receiving so receipt dates and costs attach to identifiable lots when needed—covered in barcode inventory systems explained.
LIFO in Accounting
Newest costs to COGS first.
LIFO assigns the latest purchase costs to COGS when prices climb, reducing taxable income in the US under permitted conditions. Balance sheet inventory can look understated versus replacement cost. IFRS prohibits LIFO; US GAAP allows it with LIFO conformity rules that constrain switching methods.
LIFO liquidation—selling into older layers after inventory draws down—can spike COGS downward and create tax surprises. Finance should model layer aging alongside inventory forecasting so ops does not unintentionally exhaust cheap layers during promotions.
Average Cost and Hybrid Practices
When layers are impractical.
Weighted average recalculates unit cost after each receipt—simple for commingled bulk materials and many cloud SMB tools. Specific identification applies to high-value unique items where each unit has its own cost basis.
Compare platforms in Zoho Inventory vs Cin7 and inFlow Inventory vs Zoho Inventory for costing exports to your GL. Tracking discipline from the easiest ways to track inventory still underpins any costing method—garbage quantities produce garbage COGS regardless of FIFO or LIFO.
Operations vs Finance: FEFO, FIFO, and Audits
Align warehouse rules with the ledger.
Warehouse FEFO prioritizes earliest expiry dates to reduce waste; accounting FIFO prioritizes earliest purchase costs for COGS. You may pick FEFO on the floor while finance runs FIFO layers—document both policies so auditors do not assume pick order equals cost flow.
Cycle counts validate quantities that costing methods rely on; AI variance hints in how AI is used in inventory management do not replace count discipline. Prevent margin distortion from shrink by pairing costing reviews with overstocking and stockout prevention practices.
FAQs
Quick answers to common questions.