LIFO

LIFO, short for last in, first out, is an inventory cost-flow method that assigns the most recently acquired or produced costs to cost of goods sold first. Older cost layers remain in ending inventory until quantities fall enough to liquidate them.

LIFO is permitted under U.S. GAAP and can be elected for U.S. federal tax purposes when its requirements are met. IFRS does not permit LIFO. That framework difference makes direct comparison between LIFO and non-LIFO companies difficult without adjusting the reported inventory and earnings effects.

Key Takeaways

• LIFO assigns recent costs to expense and leaves older cost layers in ending inventory.
• When costs rise, LIFO generally produces higher cost of goods sold, lower gross profit, and lower ending inventory than FIFO.
• A reduction in inventory quantities can release old, low-cost layers and temporarily increase profit; this is a LIFO liquidation.
• The LIFO reserve disclosed by many U.S. companies helps analysts estimate inventory and cost of goods sold on a FIFO-like basis.
• LIFO tax use requires an election and continuing compliance; a reported tax benefit is generally a timing deferral, not free economic value.

Worked Example: LIFO Cost Assignment

Assume a retailer has:

The retailer sells 120 units for $18 each. Under LIFO, the newest costs are assigned first:

LIFO cost of goods sold = (100 x $12) + (20 x $10) = $1,400

LIFO ending inventory = 80 x $10 = $800

Gross profit = (120 x $18) - $1,400 = $760

Under FIFO, the same facts produce $1,240 of cost of goods sold, $960 of ending inventory, and $920 of gross profit. LIFO does not change the units sold or cash sales; it changes which cost layers are recognized.

How LIFO Layers Work

Each period in which ending quantities increase can create a new layer measured at that period’s cost. If quantities remain stable or rise, old layers can stay on the balance sheet for years. Their carrying amounts may be far below current replacement cost.

Companies with large, diverse inventories often use pools and price indexes rather than tracking every physical unit as a separate layer. Dollar-value LIFO, for example, measures changes in inventory pools after removing price-level effects. These systems are more complex than the simple unit example but preserve the same principle: newer cost increments are treated as sold first.

LIFO Liquidation

A LIFO liquidation occurs when inventory quantities or pools decline enough that old cost layers move into cost of goods sold. In a rising-cost environment, releasing an old low-cost layer can reduce cost of goods sold and increase reported profit even while the business is shrinking inventory.

Suppose current replacement cost is $15 per unit, but an old LIFO layer carries 1,000 units at $6. If a sales surge or supply shortage liquidates that layer, current-period cost of goods sold can include the $6 historical cost rather than a current $15 cost. The margin increase may not be repeatable.

Analysts should review inventory quantities, LIFO liquidation disclosures, and management’s explanation before treating the resulting gross margin as operating improvement.

Understanding the LIFO Reserve

The LIFO reserve is the cumulative difference between inventory measured under another stated basis, commonly FIFO, and inventory reported under LIFO.

A simplified adjustment is:

FIFO-like inventory = reported LIFO inventory + LIFO reserve

The period-to-period change in the reserve can help bridge LIFO cost of goods sold toward a FIFO-like amount:

FIFO-like COGS = LIFO COGS - increase in LIFO reserve

If the reserve falls, the adjustment reverses direction and may signal liquidation or price changes. Tax effects, mixed inventory methods, acquisitions, foreign operations, and company-specific definitions must be considered before using the bridge in valuation.

LIFO Under U.S. GAAP, IFRS, and Tax Rules

IRS guidance explains that a taxpayer adopts LIFO by filing Form 970 or the required statement with a timely return for the first LIFO year. Switching methods or changing a LIFO submethod can require consent and Form 3115 procedures.

Tax results depend on the Internal Revenue Code, regulations, elections, entity facts, and later recapture or method changes. A lower current tax payment during inflation is generally a deferral linked to higher tax cost of goods sold, not a guaranteed permanent saving.

Periodic and Perpetual LIFO

Periodic LIFO applies the last-in assumption after total purchases and period-end quantities are known. Perpetual LIFO updates layers after each transaction. Because purchase and sale sequencing can differ during the period, the two systems can produce different ending inventory and cost of goods sold even with the same total units.

When reviewing a company, the label “LIFO” alone may not reveal its pools, indexes, submethods, or whether all inventory categories use LIFO.

How Analysts Should Evaluate LIFO Reporting

1. Read the inventory policy and identify which inventory classes and geographies use LIFO.
2. Record the LIFO reserve and its year-over-year change.
3. Check for LIFO liquidation and separate its margin effect from operating performance.
4. Compare inventory quantities, not only dollar balances affected by inflation.
5. Adjust inventory, cost of goods sold, taxes, and ratios consistently if building a FIFO-like comparison.
6. Review lower-of-cost-or-market charges and whether inventory pools contain old costs.
7. Distinguish financial-reporting LIFO from the exact tax method and election.

Common Mistakes and Limitations

• Assuming LIFO tracks physical movement: It is a cost-flow method, not a warehouse instruction.
• Treating lower profit as worse economics: During inflation, LIFO can match more recent costs with current revenue while reducing reported inventory.
• Ignoring liquidation gains: Profit can rise because quantities fell into old layers.
• Adding the reserve only to inventory: A complete comparison may also require cost-of-goods-sold, tax, and equity adjustments.
• Applying LIFO internationally: IFRS financial statements cannot use LIFO.
• Calling tax deferral tax avoidance: Method elections operate within detailed tax rules and can reverse economically or through later events.

This page is educational and is not accounting, tax, legal, or investment advice.

Official Resources

• IRS: About Form 970 explains the election to use the LIFO inventory method for U.S. federal tax purposes.
• IRS Publication 538 compares FIFO and LIFO and describes tax inventory methods.
• FASB ASU 2015-11, Inventory (Topic 330) preserves the lower-of-cost-or-market model for LIFO and retail-method inventory.
• IFRS Foundation: IAS 2 Inventories lists the cost formulas permitted under IFRS.

Related Terms

• FIFO
• Inventory Accounting
• Inventory
• Cost of Goods Sold
• Lower of Cost or Market