How to Calculate Inventory Value: FIFO, LIFO and Weighted Average

To calculate inventory value, multiply the quantity of each item on hand by its unit cost, then add every line together. The judgment call is which unit cost to use when you bought the same item at different prices over time, and that is decided by your costing method: FIFO (first in, first out), LIFO (last in, first out) or weighted average cost. All three value the same physical stock differently, so the method you pick changes your reported inventory value, your cost of goods sold and your taxable profit. Most US businesses use FIFO or weighted average; whichever you choose, apply it consistently, because switching methods mid-stream distorts the comparison from one period to the next.

Inventory value is not just a bookkeeping number. It sits on your balance sheet as an asset, it drives cost of goods sold on your income statement, and it decides how much cash is locked in stock. Getting it right is the difference between knowing your real margin and guessing at it.

What is inventory value?

Inventory value is the total cost of all the goods you are holding to sell, measured at what you paid for them, not what you will sell them for. It is recorded at cost under standard US accounting, and it appears as a current asset on the balance sheet. The figure matters because it feeds two others: the cost of goods sold you expense when items sell, and the working capital tied up in stock at any moment. A clear read on that second number is the whole point of watching inventory carrying cost.

How do you calculate inventory value?

Take the quantity on hand for each SKU, multiply by its unit cost, and sum across every SKU. If you bought a SKU at one steady price, that is the whole calculation. The complication is real inventory: you buy the same item repeatedly at prices that move, so at any moment your on-hand units were bought at a mix of costs. The costing method decides which of those costs you assign to the units still on the shelf.

A worked example

Say you bought 100 units at $10 in January and 100 units at $14 in March, then sold 120 units. You have 80 units left. Under FIFO, the 120 you sold are the oldest first, so the 80 remaining are the newest, valued at $14 each: inventory value is $1,120. Under LIFO, the 120 sold are the newest first, so the 80 remaining are the oldest, valued at $10 each: inventory value is $800. Under weighted average, every unit is valued at the blended cost of $12 ($2,400 spent on 200 units), so 80 units are worth $960. Same physical stock, three different values.

FIFO vs LIFO vs weighted average

The three methods differ only in which cost they attach to units sold versus units held. Here is how they compare on the points that matter for a US business.

When prices are rising, FIFO reports a higher inventory value and higher profit, while LIFO reports lower profit and so a lower tax bill. That tax effect is the main reason a US business would choose LIFO, but it is banned under international standards, so companies that report globally avoid it. Weighted average is the pragmatic middle and the easiest to automate across thousands of SKUs.

Why does inventory value matter for your business?

Because it flows straight into the numbers you run the business on. Ending inventory value sets your cost of goods sold, which sets gross margin. It is the largest current asset on many balance sheets, so it shapes how lenders and buyers read the company. And it is a direct measure of cash you cannot spend until the stock sells. When you value inventory accurately, the figure flows cleanly onto your financial statements and your margin stops being a guess.

How often should you value inventory?

At minimum at each period close for your financial statements, but a perpetual system that updates value on every receipt and sale gives you the number any day you need it. The gap between the two approaches is the gap between finding out your true stock position once a quarter and knowing it continuously. Continuous valuation also makes ratios like inventory turnover and days of inventory on hand trustworthy, because they depend on an accurate average inventory value.

From value to decision

Knowing what your inventory is worth is the start; the payoff is using it to hold less of the wrong stock. The SKUs carrying the most value are the ones where a costing error or a slow-moving pile hurts most, so they deserve the tightest review. Feeding an accurate per-SKU value into inventory control software is what turns a static balance-sheet number into a live signal about which stock to reorder and which to clear.

To see which SKUs are holding the most value and moving the slowest right now, paste your stock and sales into the live stock scan at the top of the site. It returns per-SKU verdicts on cover and slow movers, so the stock quietly locking up the most cash is the first thing you see.