LIFO Reserve and the FIFO Conversion for Inventory and COGS
The LIFO reserve is the difference between a company’s inventory cost under FIFO (first-in, first-out) and under LIFO (last-in, first-out). The formula is LIFO reserve = FIFO inventory − LIFO inventory. Add the reserve to LIFO inventory to get FIFO inventory, and subtract the change in the reserve from LIFO cost of goods sold (COGS) to get FIFO COGS.
One calculation uses a balance at a date (the ending reserve). The other uses the movement between two dates (the change in the reserve). A few companies measure the reserve against average cost or current cost instead of FIFO, so always check which basis the inventory note uses.
Suppose two distributors sell the same goods at the same price and pay the same suppliers. They can still report different gross profits because they assign different purchase costs to the goods sold. The inventory note can give you enough information to compare them on the same basis.
Prefer to watch first? This Farhat Lectures video explains the LIFO reserve. Then work through the example below to lock it in.
What does the LIFO reserve measure?
Imagine a distributor that keeps its inventory records on FIFO. Its managers can use recent purchase costs in ending inventory when considering selling prices. The company nevertheless reports inventory under LIFO. At the reporting date it can reconcile the two systems with a contra-inventory account (an account that reduces the inventory balance), often called Allowance to Reduce Inventory to LIFO. A credit balance in that account reduces the inventory amount shown on the balance sheet.
New to cost flow methods? Start with FIFO vs LIFO: how inventory costs change profit and taxes, or compare all four inventory cost flow assumptions side by side.
Using an allowance preserves the detailed internal records. That can matter when staff use those records to set prices or when a compensation plan uses internal margins. It also allows the year-end LIFO calculation to be made after final quantities and costs are known.
Read the comparison basis first. A company may maintain internal records at average cost. An allowance measured against average cost reconciles to that basis. To make an exact FIFO conversion, use a disclosure or problem that specifically identifies FIFO.
In one sentence: the LIFO reserve is the cumulative amount by which LIFO has pushed inventory below its FIFO cost, and it usually grows when purchase prices are rising.
LIFO reserve formula and the annual LIFO effect
Assume that the reserve is defined as FIFO inventory less LIFO inventory throughout the problem. Treat a decrease in the reserve as a negative change.
| Question | Calculation |
|---|---|
| How much is the ending reserve? | FIFO ending inventory − LIFO ending inventory |
| What is the annual LIFO effect? | Ending reserve − beginning reserve |
| What is FIFO ending inventory? | LIFO ending inventory + ending reserve |
| What is FIFO COGS? | LIFO COGS − change in reserve |
You can recover the COGS rule from the inventory equation. Under either method, COGS equals beginning inventory plus purchases minus ending inventory. Converting to FIFO adds the beginning reserve to beginning inventory and the ending reserve to ending inventory. With the same purchases, the net adjustment to COGS is the beginning reserve less the ending reserve.
Not sure how periodic and perpetual records change these numbers? See periodic vs perpetual inventory costing with a worked example.
Worked example and year-end journal entry
In this hypothetical example, Harbor Beacon Supply begins the year with a $9,000 credit in its allowance. At year-end, the FIFO ledger shows inventory of $146,000. A separate LIFO calculation gives $132,000. The required closing credit balance is $14,000. Because the allowance already holds $9,000, the company records only the $5,000 increase.
| Account | Debit | Credit |
|---|---|---|
| Cost of goods sold | $5,000 | — |
| Allowance to reduce inventory to LIFO | — | $5,000 |
After posting, the inventory presentation is $146,000 less $14,000, or $132,000. If unadjusted FIFO COGS was $301,000, reported LIFO COGS is $306,000. An analyst starting with the published figures reverses the comparison on a worksheet: $132,000 + $14,000 gives FIFO inventory, and $306,000 − $5,000 gives FIFO COGS. The analyst makes no entry in Harbor Beacon’s books.
How does the reserve affect the current ratio?
Suppose Harbor Beacon reports $240,000 of current assets, including its LIFO inventory, and $150,000 of current liabilities. Its reported current ratio is 1.60. On a FIFO inventory basis, current assets become $254,000, and the ratio becomes approximately 1.69. This simple comparison holds all other balances fixed. The ratio changed even though the company received no cash and still owns exactly the same goods.
For an actual filing, check what management discloses. For SEC registrants covered by the rule, a material excess of replacement or current cost over the stated LIFO amount must be disclosed. That wording matters because replacement cost and FIFO are distinct measurements. Caterpillar’s inventory note, for example, expressly identifies FIFO as its comparison. In its 2024 annual report, Caterpillar said LIFO covers about 65 percent of its inventories, and that inventories would have been $3,864 million higher at December 31, 2024, and $3,423 million higher at December 31, 2023, under FIFO. Apply the formula and the reserve grew by $441 million during 2024, so Caterpillar’s 2024 cost of goods sold would have been about $441 million lower on a FIFO basis. Regulation S-X, Rule 5-02.6(c) · Caterpillar 2024 Form 10-K, Note 1.C
How do you adjust net income and retained earnings for the LIFO reserve?
When the LIFO reserve increases, converting to FIFO lowers COGS and raises pretax income. When the reserve decreases, converting to FIFO raises COGS and lowers pretax income. The net-income adjustment uses the change in the reserve during the period. The cumulative retained-earnings adjustment uses the ending reserve. The formulas below assume a FIFO-based reserve, a constant tax rate across the periods included in the reserve, and reserve changes arising through COGS.
| Item | Formula |
|---|---|
| FIFO net income | LIFO net income + change in reserve × (1 − tax rate) |
| FIFO retained earnings | LIFO retained earnings + ending reserve × (1 − tax rate) |
Back to Harbor Beacon, assume a constant 21% tax rate. The reserve grew by $5,000, so FIFO pretax income is $5,000 higher in the analyst’s comparison. The corresponding income tax expense adjustment is $1,050 ($5,000 × 21%), and the net-income adjustment is $3,950 ($5,000 × 79%).
For this analytical balance-sheet restatement, the full $14,000 reserve increases inventory, and retained earnings increase by $11,060 ($14,000 × 79%). Assume that inventory’s tax basis remains its LIFO amount and that there are no other book-tax differences in the example. The $14,000 increase in the analytical carrying amount creates a taxable temporary difference, giving a $2,940 deferred tax liability ($14,000 × 21%) for the assumed future recovery of that difference. These amounts are adjustments on the analyst’s worksheet.
Why do companies use LIFO, and does IFRS allow it?
When purchase prices rise, LIFO matches the newest, highest costs against sales. That raises COGS and lowers taxable income, which is the main reason U.S. companies choose it.
The LIFO conformity rule generally requires a company using LIFO for tax purposes to use LIFO in its primary presentation of annual income, profit, or loss to owners and creditors. The regulations permit specified supplemental non-LIFO disclosures, including qualifying notes that accompany the financial statements.
LIFO is permitted under U.S. GAAP (FASB ASC 330, Inventory) but prohibited under IFRS (IAS 2, Inventories). A company reporting under IFRS has no LIFO reserve to analyze.
Practice questions
1. Inventory is $82,000 on LIFO and the FIFO-based reserve is $11,000. What is FIFO inventory?
$93,000. Add the cumulative $11,000 difference to the amount reported at year-end.
2. The reserve falls from $12,000 to $8,000. LIFO COGS is $175,000. What is FIFO COGS?
$179,000. The change is negative $4,000. Subtracting that negative amount increases COGS by $4,000.
3. A $7,500 credit allowance must end at $6,000. What is the adjusting entry on FIFO books?
Debit the allowance $1,500 and credit COGS $1,500. The debit reduces the existing credit balance to the required amount.
4. LIFO net income is $60,000, the reserve rose by $10,000, and the tax rate is 21%. What is FIFO net income?
$67,900. FIFO COGS is $10,000 lower, which adds $10,000 × (1 − 0.21) = $7,900 after tax. $60,000 + $7,900 = $67,900.
Common LIFO reserve mistakes to avoid on exams
These are the slips that cost students points on intermediate accounting and CPA FAR questions:
- Adding the change in the reserve to inventory. Inventory uses the ending balance. COGS uses the change.
- Adding the change to COGS. A growing reserve means FIFO COGS is lower, so you subtract the change.
- Losing the sign when the reserve falls. A decrease is a negative change, and subtracting a negative raises FIFO COGS.
- Forgetting taxes. Net income and retained earnings move by the after-tax amount, not the full reserve.
- Assuming the basis is FIFO. If the note says current cost, replacement cost, or average cost, the reserve will not give you an exact FIFO figure.
Interactive LIFO reserve and LIFO effect quiz
The LIFO reserve is the difference between inventory measured on the comparison basis and under LIFO. The LIFO effect is the change in that reserve during the period. Use this four-question quiz to practice how the adjustment affects ending inventory and cost of goods sold.
Key takeaways
- The LIFO reserve equals FIFO inventory minus LIFO inventory at a point in time.
- The LIFO effect is the change in the reserve during the year.
- FIFO inventory = LIFO inventory + ending reserve.
- FIFO COGS = LIFO COGS − change in reserve.
- FIFO net income = LIFO net income + change in reserve × (1 − tax rate).
- A company that keeps FIFO or average-cost books records a growing reserve with a debit to COGS and a credit to Allowance to Reduce Inventory to LIFO.
- A positive FIFO-based LIFO reserve can indicate cumulative income tax deferral when LIFO is also used for tax purposes. The estimate depends on the applicable tax rate and book-tax differences.
Frequently asked questions
Is the reserve cash available for purchases?
No. It reconciles two cost measurements of the same goods, and the year-end entry itself does not move cash. Using LIFO for tax purposes can defer income taxes when prices rise. The LIFO conformity rule generally requires LIFO in the primary presentation of annual income, profit, or loss to owners and creditors, while allowing specified supplemental non-LIFO disclosures. Assuming a FIFO-based reserve, matching book and tax inventory costs under LIFO, and a constant 21% tax rate, Harbor Beacon’s $14,000 reserve corresponds to an estimated $2,940 cumulative tax deferral.
Can the reserve stay positive while its annual change is negative?
Yes. A drop from $12,000 to $8,000 leaves a positive ending balance and produces a negative $4,000 annual change.
Does a shrinking reserve prove there was a liquidation?
A price decline can also narrow the difference. To identify a liquidation, look for a reduction in a prior inventory layer. See how a LIFO liquidation affects gross profit.
Is the LIFO reserve the same as the LIFO effect?
No. The reserve is a balance at a date. The LIFO effect is the change in that balance during the period. In the Harbor Beacon example, the reserve is $14,000 and the LIFO effect is $5,000.
Can the LIFO reserve be negative?
Yes, though it is rare. If prices fall for long enough, LIFO inventory can end up higher than FIFO inventory, and the difference reverses.
Where do I find the LIFO reserve in a 10-K?
Look in the inventory note or the summary of significant accounting policies. SEC rules require commercial and industrial companies that use LIFO to disclose a material excess of replacement or current cost over the LIFO amount, either in parentheses on the balance sheet or in a note.
Does IFRS allow LIFO?
No. IAS 2 does not permit LIFO, so companies reporting under IFRS have no LIFO reserve.
Studying for FAR or working through intermediate accounting? Try the Farhat Lectures free sample course and see how the lessons fit your study plan.
Written by Mansour Farhat, who teaches accounting and CPA, CMA, and EA exam prep through Farhat Lectures and its YouTube channel.
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