FIFO vs LIFO vs Weighted Average: Which Costing Method Is Right for Your Business?
Most business owners never consciously choose an inventory costing method. They either inherit whatever their accountant set up, or the software picks a default and they go with it.
That's a problem. Because your costing method doesn't just affect your accounting — it affects how much tax you pay, what your gross margin looks like, and whether your balance sheet reflects reality.
Here's what each method actually does, with plain numbers.
Why This Decision Matters More Than You Think
Suppose you buy 100 units of a product at Rs. 100 each in January. Then you buy another 100 units at Rs. 130 each in March (costs went up). You sell 80 units in April.
Under different costing methods, your cost of goods sold for those 80 units is:
- FIFO: Rs. 8,000 (using the January stock first)
- LIFO: Rs. 10,400 (using the March stock first)
- Weighted Average: Rs. 9,200 (blended cost of Rs. 115)
Same business. Same 80 units sold. Three different profit numbers — and three different tax bills.
FIFO — First In, First Out
FIFO assumes you sell the oldest inventory first. In practice, most physical businesses actually operate this way — especially in food, pharma, and anything with an expiry date.
The accounting reality: When prices are rising (inflation), FIFO produces lower COGS because you're costing sales at older, cheaper prices. This means higher reported profit — and a higher tax bill.
The balance sheet reality: Your remaining inventory is valued at the most recent (higher) costs, which more accurately reflects what it would cost to replace that stock.
Who it suits: Businesses that physically rotate stock (food and beverage, pharma, consumer goods), businesses in stable or declining cost environments, and businesses that want their balance sheet inventory value to be meaningful.
If you're running a food and beverage operation, FIFO isn't just an accounting preference — it's how you should actually be moving stock. The accounting method should mirror the physical reality. If you're not sure whether your inventory operations match your costing method, the gap usually shows up as shrinkage or unexplained margin erosion.
LIFO — Last In, First Out
LIFO assumes you sell your newest inventory first.
Here's the honest reality: most countries don't allow LIFO under their accounting standards. IFRS (used in Nepal and most of the world) prohibits it. US GAAP allows it, which is why you'll see it discussed in American business content.
If you're operating in Nepal or South Asia, LIFO is generally not an option. Your accountant will confirm this. So the real choice is between FIFO and weighted average.
The main conceptual benefit of LIFO — in rising price environments, it produces higher COGS and lower reported profit, reducing your current tax burden — is not available to most businesses.
Weighted Average Cost
Weighted average takes the total cost of all units available and divides by total units to get an average cost per unit. Every sale uses this blended average.
Example using the same numbers:
- 100 units at Rs. 100 = Rs. 10,000
- 100 units at Rs. 130 = Rs. 13,000
- Total: 200 units at a weighted average of Rs. 115
- Cost of 80 units sold: Rs. 9,200
The accounting reality: In volatile price environments, weighted average smooths out the peaks and troughs. Your margin doesn't swing dramatically based on whether you happen to sell older or newer stock.
The balance sheet reality: Your inventory is valued at a blended cost that doesn't perfectly reflect either current replacement cost or the true cost of specific units on hand.
Who it suits: Businesses with commoditized or fungible inventory where tracking individual purchase costs would be impractical. Businesses with high purchase frequency and moderate price volatility. Many wholesale and distribution businesses find this the most practical method.
If you're trying to understand why your margins look stable even when costs are moving, or why they're swinging more than expected, your costing method is usually part of the explanation. This connects closely to how you handle landed cost calculations — because landed cost needs to be folded into whichever costing method you use, and many businesses forget to include freight, duties, and handling.
The Landed Cost Wrinkle
Both FIFO and weighted average get more complicated when you're importing goods. Your purchase price is one number, but the actual cost of getting that unit into your warehouse — including freight, insurance, customs, and duties — is higher.
If you're using FIFO, you need to assign the landed cost to the specific batch. If you're using weighted average, the landed costs need to be blended into the average. Either way, ignoring landed costs means your inventory is undervalued on the balance sheet and your margin is overstated on the P&L.
Periodic vs Perpetual: The Other Variable
Beyond the costing method, you also need to choose between:
Periodic inventory — You count inventory at set intervals (monthly, quarterly, annually) and calculate COGS as a reconciliation. Simple, but always running on slightly stale numbers.
Perpetual inventory — Every sale, purchase, and adjustment updates inventory values in real time. Your books always reflect what's actually in the warehouse.
For any business using inventory management software, perpetual inventory is the standard. The system calculates COGS automatically at the point of each sale. You don't need to wait for a count.
Periodic inventory made sense when everything was done in ledgers. In 2026, it's a limitation, not a choice.
How to Choose
For most wholesale, distribution, and manufacturing businesses:
Use FIFO if:
- Your products have expiry dates or you physically rotate stock FIFO
- You want your balance sheet inventory to reflect current replacement costs
- Your purchase prices are relatively stable or declining
Use Weighted Average if:
- You deal in commoditized products where batches aren't meaningfully different
- You have frequent purchases with moderate price changes
- You want smoother margin reporting
Use Specific Identification if:
- You deal in high-value, unique items (vehicles, equipment, custom orders)
- You need to track exactly which unit was sold and what it cost
Whatever you choose, consistency matters. Switching methods mid-year creates accounting complications and requires restating prior periods.
Making Sure Your Software Handles It Correctly
Your costing method is only as good as the system implementing it. A common problem is that businesses choose FIFO but their inventory system doesn't actually enforce FIFO dispatch sequences — it just uses purchase order date as a proxy, which isn't the same thing.
This matters a lot when you're doing inventory valuation for month-end or trying to explain a margin variance to your finance director.
Before you settle on a method, confirm your system actually calculates it correctly. Run a test: create two purchase batches at different prices, sell some units, and verify the COGS matches what you'd expect under your chosen method.
Most businesses stick with whatever their accountant set up at the beginning and never revisit it. That's usually fine — but knowing why you're using a particular method, and what it means for your numbers, is the kind of financial literacy that separates operators who run their business from operators who just react to it.
Sevenledger's accounting software supports FIFO and weighted average costing, with landed cost assignment built in. Every inventory movement writes the correct journal entry automatically — no manual COGS calculations at month-end.