The LIFO method, short for Last In, First Out, is an inventory accounting approach that assumes the most recently purchased items are the first to sell. After guiding dozens of small business owners through inventory decisions, I can tell you the LIFO method is one of the more powerful tax-planning tools available, but it is not a fit for every business.
In this guide I walk through exactly how the LIFO method works, when it helps, when it hurts, and how it compares to alternatives like FIFO and weighted average. If you hold inventory and your costs have been rising, this is worth reading before your next tax filing.
What is the LIFO method?
The LIFO method is an inventory costing system where the newest units you bought or produced are matched against sales first. When you record a sale, cost of goods sold reflects the most recent purchase prices, and your remaining inventory on the balance sheet carries the older, often lower, costs.
During periods of rising prices, the LIFO method produces higher cost of goods sold and lower taxable profit than FIFO. That means a smaller tax bill in the current year, which is the biggest reason US businesses choose LIFO in the first place.
A quick LIFO example
Say you run a plumbing supply shop. In January you buy 100 copper fittings at $5 each, then in October you buy another 100 at $8 each. You sell 120 fittings during the year.
Under the LIFO method, cost of goods sold comes off the newest layer first. That is 100 units at $8 plus 20 units at $5, for a total COGS of $900. Your remaining 80 units are valued at the older $5 cost, or $400 of ending inventory.
LIFO method advantages
The primary advantage of the LIFO method is tax deferral during inflation. Because cost of goods sold is higher, reported profit is lower, and your federal and state income tax bill falls in the current year.
A second benefit is better matching of revenue and cost. Your income statement shows current-period sales matched against current-period costs, which gives a more accurate picture of gross margin under today’s pricing conditions.
LIFO method disadvantages
The biggest disadvantage is a weaker looking balance sheet. Because old, cheap inventory layers stay on your books, ending inventory is understated, working capital looks thinner, and lenders may see a less impressive snapshot of the business.
LIFO also creates a compliance headache. It is only allowed under US Generally Accepted Accounting Principles. If you ever plan to pursue international investors, file under IFRS, or sell the business to a buyer that uses international standards, you will need to restate inventory.
LIFO method vs FIFO method
LIFO and FIFO produce opposite results during inflation. The LIFO method gives you higher COGS and lower current taxes, while the FIFO method gives you lower COGS and a cleaner balance sheet but a higher current tax bill.
For the opposite side of the coin, see our FIFO method guide. A quick rule I use with clients: if preserving cash through taxes matters more than impressing lenders, LIFO is worth modeling. If you plan to raise money or sell the business, FIFO is usually the safer call.
LIFO method vs weighted average
Weighted-average costing blends all inventory into a single unit cost, while the LIFO method tracks discrete purchase layers and always pulls from the newest one first. The LIFO method provides sharper tax planning, while weighted average is easier to administer.
If you have only a handful of SKUs and relatively stable costs, weighted average may be fine. If you have rising costs and want to cut current-year taxes, the LIFO method is worth the extra bookkeeping.
How to calculate the LIFO method step by step
First, record every purchase as a separate layer with the date, quantity, and unit cost. Second, record each sale and pull from the newest unused layer first. Third, continue to pull from the next newest layer once the most recent one is exhausted. Fourth, at period end, multiply remaining units by the unit cost of the oldest layers to get ending inventory.
Modern inventory software such as QuickBooks, Xero, or NetSuite supports LIFO tracking. Make sure your bookkeeper or CPA confirms the setting and that your general ledger matches your inventory subledger each period.
LIFO reserve and what it tells you
Businesses using the LIFO method are required to disclose a LIFO reserve, which is the difference between LIFO and FIFO inventory values. That single number tells readers how much higher your inventory would be under FIFO.
The LIFO reserve matters for lenders and investors who want to compare your financials against competitors that use FIFO. It is also useful for internal decision-making because it shows the cumulative tax benefit you have banked from the method.
Tax considerations of the LIFO method
The IRS allows the LIFO method, but with strict consistency requirements. Once you elect LIFO, you must use it on both your books and your tax return. Switching methods requires filing Form 3115 and usually involves a multi-year spread of any catch-up adjustment.
Always verify the latest IRS guidance at irs.gov or consult a CPA before electing LIFO. The paperwork and recordkeeping burden is real, and an incorrect election can trigger adjustments that erase the benefit.
When the LIFO method is the right choice
The LIFO method usually makes sense for businesses with durable, non-perishable inventory, steadily rising costs, and a desire to defer taxes. Common examples include industrial distributors, auto parts resellers, and commodity-based businesses.
It is less suitable for perishable goods, fashion, or technology because physical flow genuinely runs first-in, first-out. In those cases the LIFO method creates a mismatch between accounting and operations that is hard to explain to stakeholders.
LIFO liquidation risk
If you let inventory run down below long-held LIFO layers, you pull the old, cheap costs into COGS and suddenly report a large taxable profit. This is called a LIFO liquidation, and it can blow up your tax plan in a single year.
Plan purchases around key period-end dates to maintain your layers. Many LIFO businesses run a quick end-of-year check to replenish inventory before December 31 for exactly this reason.
How to decide if the LIFO method is right for you
Ask three questions. Are your input costs rising year over year? Do you plan to hold physical inventory for several years? Are you comfortable with additional bookkeeping and disclosure work?
If you answered yes to all three, model LIFO against FIFO with a CPA. If you are not sure where to start with your books, our self-employed bookkeeping guide covers the foundations that must be in place before any inventory method will pay off.
Frequently asked questions about the LIFO method
What is the LIFO method in simple terms?
The LIFO method is an inventory accounting approach where the last units purchased are treated as the first ones sold. Cost of goods sold reflects the most recent purchase prices, and your remaining inventory carries the older, usually lower, costs.
Is the LIFO method allowed in the United States?
Yes, the LIFO method is allowed in the United States under both the Internal Revenue Code and US GAAP. It is not allowed under international financial reporting standards, which is why many multinational businesses avoid it.
Why would a business choose LIFO over FIFO?
Businesses choose the LIFO method over FIFO mainly to reduce current-year taxable income when their inventory costs are rising. Higher COGS means lower taxable profit, which translates to real cash tax savings in inflationary periods.
What is LIFO liquidation and why does it matter?
LIFO liquidation happens when a business depletes inventory below its long-held older layers, forcing those cheap costs into cost of goods sold. This causes a spike in taxable profit and can wipe out the tax benefit of using LIFO that year.
Does the LIFO method work for perishable inventory?
The LIFO method is a poor fit for perishable inventory because physical flow runs oldest first, while LIFO accounting pulls from the newest layer. That mismatch makes the method harder to explain and reconcile against real operations.
How do I switch from LIFO to another inventory method?
To switch from LIFO to another inventory method, you generally must file IRS Form 3115, Application for Change in Accounting Method. The change usually spreads the cumulative adjustment over multiple years, and most business owners work with a CPA because the filing is complex.
What is a LIFO reserve?
A LIFO reserve is the difference between inventory valued under the LIFO method and inventory valued under FIFO. Businesses using LIFO are required to disclose this reserve so that lenders and investors can compare results against companies that use FIFO.
Is the LIFO method better than weighted average?
The LIFO method is usually better than weighted average for reducing current-year taxes during inflation. Weighted average is simpler to administer but offers no specific tax advantage, so the choice comes down to whether bookkeeping simplicity or tax savings matters more.
