FIFO and LIFO are inventory flow methods that decide which items leave a warehouse first. FIFO means First In, First Out, so the oldest stock is shipped before newer stock. LIFO means Last In, First Out, so the newest stock is shipped first.
These systems matter because they affect product freshness, storage layout, labor time, and inventory records.
In a FIFO warehouse, products usually move through the system in one direction, such as from a receiving dock to storage to a shipping dock. This helps prevent expired, damaged, or outdated goods from sitting too long. In a LIFO warehouse, goods may be stored and removed from the same side, which can be faster and simpler for nonperishable items.
Choosing the right method depends on shelf life, access rules, cost tracking, and how the warehouse is physically arranged.
Understanding Logistics & Warehouse Systems: FIFO vs LIFO
The rule on paper only works when the warehouse layout supports it. A rack with access from both ends can receive cases on one side and release them from the other. This creates a steady flow through the rack.
Gravity flow racks use rollers so cartons move forward as space opens. Pallet lanes can work in a similar way. When staff must reach past newer pallets to find an older one, the process takes longer and errors become more likely.
Warehouse software helps by assigning each pallet a location, batch number, receipt date, and sometimes a serial number. Barcode scans confirm that the picker removed the intended unit.
Inventory flow has a financial side as well as a physical side. The cost recorded for a sale depends on which purchase cost is treated as leaving inventory. When supplier prices rise, using older costs for sales usually leaves newer and more expensive stock in the inventory record.
This can make reported profit appear higher. Using newer costs first can produce a lower reported profit in the same situation. A business may use one method for moving real goods and another method for financial reporting, depending on its rules.
Accounting standards differ by country. For example, LIFO is not allowed under International Financial Reporting Standards.
Date labels create a more precise system called first expired, first out. It is common for food, medicine, cosmetics, and chemicals. A carton received later may need to leave sooner if its expiry date is closer.
Workers must check the date printed on each batch rather than relying only on the delivery date. Temperature matters too. A product can become unsafe or lose quality if it is stored outside its required range, even when stock rotation is correct.
Good rotation reduces waste, but it cannot repair damaged packaging or a broken cold chain. Traceable batch records are important during a product recall because staff must quickly locate every affected item.
Students should separate the physical movement of items from the records used to value them. They should notice where congestion can occur at receiving, storage, picking, packing, or dispatch. Inventory turnover is found by dividing cost of goods sold by average inventory.
Average inventory is beginning inventory plus ending inventory, divided by two. A high turnover rate can mean products are selling steadily, though it can also mean the business risks running out of stock.
A low rate can indicate slow sales, excess buying, or goods held for seasonal demand. Small classroom examples with dated cartons and changing prices make these tradeoffs easier to see.
Key Facts
- FIFO = First In, First Out: oldest inventory leaves first.
- LIFO = Last In, First Out: newest inventory leaves first.
- Inventory turnover ratio = cost of goods sold / average inventory.
- Average inventory = (beginning inventory + ending inventory) / 2.
- FIFO is usually best for perishable, date-sensitive, or version-controlled products.
- LIFO can reduce handling time when items are stored and retrieved from the same access point.
Vocabulary
- FIFO
- FIFO is an inventory method where the first items received are the first items shipped or used.
- LIFO
- LIFO is an inventory method where the most recently received items are the first items shipped or used.
- Inventory Turnover
- Inventory turnover measures how many times a company sells or uses its average inventory during a period.
- Pallet
- A pallet is a flat platform used to store, move, and stack goods with forklifts or pallet jacks.
- Shelf Life
- Shelf life is the length of time a product remains usable, safe, or sellable before it expires or loses quality.
Common Mistakes to Avoid
- Assuming FIFO always means items are physically moved in a perfect straight line. FIFO is a rule for stock rotation, and the warehouse layout must be designed to support it.
- Using LIFO for perishable goods. This is wrong because older products can remain buried in storage until they expire or become unsellable.
- Confusing inventory flow with accounting cost flow. A company may track costs one way on paper, but the physical warehouse still needs a practical picking and storage process.
- Ignoring date labels and lot numbers. Even with a FIFO layout, workers need clear labels to identify which stock arrived first and should be picked first.
Practice Questions
- 1 A warehouse receives 40 cartons on Monday, 60 cartons on Tuesday, and 30 cartons on Wednesday. If it ships 70 cartons using FIFO, how many cartons remain from each day?
- 2 A storage lane holds 12 pallets loaded in this order: A, B, C, D, E, F, G, H, I, J, K, L, where A entered first and L entered last. If 5 pallets are removed using LIFO, which pallets are removed and which pallet is next to leave?
- 3 A company stores both fresh milk and metal bolts. Explain which product should use FIFO, which could use LIFO, and why the choice affects warehouse design.