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 This helps prevent expired, damaged, or outdated goods from sitting too long.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.
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.