For most U.S. businesses, LIFO is better for taxes than FIFO because inventory costs generally rise, and LIFO matches those higher, newer costs against current sales to shrink taxable income. That answer holds only while prices are climbing, only if you can live with the reporting rules that come attached, and only if you manage inventory carefully enough to avoid a delayed tax bill years down the road. Whether LIFO or FIFO is better for your taxes depends on the direction of your costs, the size of your business, and how much accounting complexity you’re willing to carry.
Why LIFO Lowers Taxes When Prices Rise
FIFO assumes you sell your oldest inventory first. In an inflationary environment, that means the cheapest units flow into Cost of Goods Sold, expenses look low, and reported profit looks high. A higher profit means a higher tax bill.
LIFO flips the assumption. The most recently purchased inventory is treated as the first sold, so the priciest units hit Cost of Goods Sold. That larger expense pulls taxable income down and defers tax to a later year. The gap between what your ending inventory would be worth under FIFO and what it’s carried at under LIFO is called the LIFO reserve, and it represents the cumulative income you’ve pushed into the future.
The savings are technically a deferral rather than a permanent cut. Over the full life of a business, total taxable income under either method would even out in theory. In practice, that rarely matters. A dollar of tax deferred today is worth more than a dollar of tax paid today, and at the 21 percent corporate rate, even a modest annual deferral compounds into real cash flow when reinvested.
The businesses that benefit most tend to carry large physical inventories exposed to persistent cost inflation. Automobile dealers, petroleum companies, and large retailers are among the most prominent LIFO users. Any business that resells goods whose costs reliably climb year over year is a natural candidate.
When FIFO Actually Wins
LIFO’s edge disappears, and can reverse, when purchase prices fall. If your newest inventory is your cheapest, LIFO assigns those low costs to Cost of Goods Sold and produces a smaller expense, higher profit, and a bigger tax bill. FIFO would recognize the older, higher costs first and reduce taxable income instead.
Sustained deflation across a whole economy is rare in the United States, but specific product categories, especially in technology and consumer electronics, see steady price declines. A company whose main inventory is in secular price decline may genuinely save on taxes by staying with FIFO.
FIFO also wins where LIFO’s benefit is too small to be worth the compliance work. Very fast inventory turnover, flat purchase prices, minimal physical goods, or a startup still building up a stockroom all point away from LIFO. If the deferral is trivial, the paperwork isn’t.
The Conformity Rule You Can’t Ignore
The biggest compliance string attached to LIFO is the conformity rule. A taxpayer that elects LIFO for federal tax purposes must also use LIFO as the primary inventory method in all financial reports issued to shareholders, partners, beneficiaries, and creditors.1Office of the Law Revision Counsel. 26 U.S. Code 472 – Last-in, First-out Inventories Congress wrote the rule to stop companies from showing low income to the IRS while showing high income to investors.
The penalty for breaking conformity is severe. The IRS can terminate the LIFO election retroactively, forcing a recalculation of past returns under FIFO along with underpayment penalties and interest going back to the year LIFO was first adopted.1Office of the Law Revision Counsel. 26 U.S. Code 472 – Last-in, First-out Inventories
Limited disclosures are allowed. You can show what your inventory would be worth under FIFO in a footnote or parenthetical, and most LIFO users disclose the LIFO reserve exactly that way so investors can still evaluate earnings.
One boundary is worth naming: International Financial Reporting Standards prohibit LIFO outright. A company that reports under both U.S. GAAP and IFRS faces a built-in conflict, because the U.S. tax election demands LIFO in the primary financials while foreign regulators and investors won’t accept it. Many multinationals pick FIFO across the board and forgo the U.S. tax savings rather than run two inventory systems.
The LIFO Liquidation Risk
LIFO carries a hidden tax bomb. Every year you add inventory, you build a new cost “layer” at that year’s prices. Over decades, your oldest layers sit at prices from years or even decades ago. As long as inventory levels stay stable or grow, those cheap layers stay untouched and the deferred tax stays deferred.
If inventory levels drop below those old layers, the cheap costs finally flow into Cost of Goods Sold. They barely move the expense needle because they reflect a different pricing era, while current revenue reflects today’s prices. Taxable income spikes, and it often spikes in a year the business is already under pressure from the same supply problems that caused the drawdown.
Congress has provided narrow relief for involuntary liquidations caused by specific events like energy supply disruptions, embargoes, or major foreign trade interruptions. The Secretary of the Treasury must publish a notice identifying the affected goods and taxpayer classes before that relief applies.2Office of the Law Revision Counsel. 26 USC 473 – Qualified Liquidations of LIFO Inventories Outside those circumstances, there is no safety valve. Any business on LIFO needs to carry enough buffer stock to avoid accidentally cutting into its oldest layers.
How to Elect LIFO
Adopting LIFO for the first time is done by filing IRS Form 970 with the income tax return for the year the election takes effect.3Internal Revenue Service. Form 970 – Application to Use LIFO Inventory Method The form asks for a description of the inventory covered, the prior valuation method, the unit of measure, and the pooling approach. An alternative election statement containing the same information is also acceptable.
Most electors use dollar-value LIFO rather than tracking individual units. Dollar-value LIFO groups related inventory into pools and measures changes in total dollar value using a price index, so items can enter and leave a pool without disrupting the calculation.4Internal Revenue Service. Introduction to Dollar Value LIFO Form 970 has a dedicated section for taxpayers electing this method.
The initial election generally does not require a Section 481(a) adjustment. Your opening inventory for the year of change simply becomes the base-year layer at its existing cost. No permission from the IRS National Office is needed beyond filing Form 970 correctly and on time.
Switching Methods Later Costs You
Changing inventory methods after the initial election is a change in accounting method and requires IRS consent through Form 3115.5Internal Revenue Service. About Form 3115 – Application for Change in Accounting Method You cannot simply start reporting under a different method on next year’s return. Many changes qualify for the automatic consent procedure, and abandoning LIFO is designated as automatic change number 56 under the current revenue procedure.6Internal Revenue Service. Changes in Accounting Periods and Methods of Accounting You still have to follow the detailed instructions in the applicable revenue procedure and file during the year of change.7Internal Revenue Service. Instructions for Form 3115
The Section 481(a) adjustment is where the pain lives. It captures the cumulative difference between what you reported under the old method and what you would have reported under the new one, so no income is counted twice or missed.8Office of the Law Revision Counsel. 26 U.S. Code 481 – Adjustments Required by Changes in Method of Accounting Switching from LIFO to FIFO almost always produces a positive adjustment: the entire LIFO reserve you built up over the years gets added back to income. Under standard automatic consent procedures, a positive adjustment is spread ratably over four tax years. A negative adjustment is taken entirely in the year of change.
Those rules reverse when the IRS forces a change during an examination. In that case the full adjustment hits in one year, positive or negative.9Internal Revenue Service. 4.11.6 Changes in Accounting Methods Voluntary compliance is meaningfully cheaper than getting caught.
Small Businesses Can Skip the Choice
Not every business has to wrestle with this decision. Small businesses that meet a gross receipts test are exempt from the general inventory accounting rules.10Office of the Law Revision Counsel. 26 U.S. Code 471 – General Rule for Inventories The threshold is based on average annual gross receipts over the three prior tax years. For 2023, that threshold was $29 million, and it adjusts annually for inflation.11Internal Revenue Service. Threshold for the Gross Receipts Test Increased to $29 Million for 2023
A qualifying business can treat inventory as non-incidental materials and supplies, deducting costs in the year items are used or consumed rather than tracking each item through a formal inventory system. That sidesteps LIFO, FIFO, and the compliance burdens attached to both. A business currently on a formal inventory system that wants to switch files Form 3115 to make the change. The same gross receipts test also exempts small businesses from the Uniform Capitalization rules under Section 263A, which otherwise require certain indirect costs like warehousing and handling to be added to inventory value rather than expensed immediately. Falling below the threshold clears both layers of complexity at once.
Two other IRS-permitted methods exist for completeness: weighted average cost, which blends all unit costs during a period, and specific identification, which tracks the actual cost of each item and works for car dealers, art galleries, and jewelers. For most companies weighing tax strategy, though, the decision still comes down to LIFO or FIFO, and it still turns on where your costs are heading and how much reporting friction you’re willing to accept in exchange for the deferral.