First In First Out (FIFO)

Definition

First In First Out (FIFO) is an inventory costing and stock rotation method that assumes the earliest acquired or produced units are issued, sold, or consumed before later units, leaving the newest costs in ending inventory.

What is First In First Out (FIFO)?

FIFO is both an accounting convention and a physical stock management principle. In accounting, it determines which inventory costs move into cost of goods sold first. In operations, it guides warehouse rotation so older stock is used or shipped before newer stock where shelf life, freshness, or obsolescence risk matters.

The method works by assigning issues and sales to the oldest available inventory layer first. As those layers are consumed, newer layers remain on hand. In periods of rising prices, that usually means older, lower costs flow to cost of goods sold while more recent, higher costs remain in ending inventory.

FIFO is widely used in manufacturing, retail, food, pharmaceuticals, and distribution because it often aligns with practical stock rotation and provides a balance sheet inventory value closer to recent replacement cost.

How FIFO Is Calculated

Under FIFO, inventory issues are priced from the oldest available cost layer first. For example, if 100 units were purchased at 10 and a later 100 units at 12, a sale of 120 units would assign 100 units at 10 and 20 units at 12 to cost of goods sold. The remaining 80 units in inventory would remain at 12.

This layered logic continues as new receipts arrive. The method therefore requires accurate quantity tracking by receipt or cost layer, even if the business automates the calculation within an ERP or inventory system.

FIFO in Warehouse Operations

Operational FIFO means older stock is picked before newer stock. Warehouses support this through location design, date coding, lot control, and disciplined receiving and picking processes. For products with shelf life or quality degradation risk, failure to rotate physically can create expiry or quality losses even if the accounting method is FIFO.

In some environments, FEFO, or first expired first out, is more appropriate than strict FIFO because expiry date rather than receipt date determines the correct issuing sequence.

FIFO vs LIFO and Weighted Average

Compared with LIFO, FIFO leaves newer costs in inventory and older costs in cost of goods sold. Compared with weighted average, FIFO preserves discrete cost layers rather than blending costs into one moving or periodic average.

These differences affect margin reporting, tax outcomes where permitted, and how closely inventory on the balance sheet reflects current market or replacement cost conditions.

When FIFO Is Most Appropriate

FIFO is especially appropriate where physical stock should move in arrival order, such as perishable products, regulated materials, or items prone to aging or obsolescence. It is also commonly selected when management prefers inventory valuation to reflect more recent acquisition costs on the balance sheet.

The method is less informative if inventory is highly fungible and price volatility is low, but it still remains widely accepted and operationally intuitive.

Limitations of FIFO

In inflationary periods, FIFO can make gross margin appear stronger because older lower costs are charged to cost of goods sold first. That may reduce comparability with replacement cost based decision making if managers do not also review current purchase prices.

Operationally, FIFO also depends on process discipline. If stock rotation in the warehouse does not match the intended issue sequence, the physical and accounting picture can diverge.

Frequently Asked Questions about First In First Out (FIFO)

Does FIFO mean the oldest stock is always physically shipped first?

Not automatically. FIFO as an accounting method determines cost flow, but physical stock movement depends on warehouse controls, location design, and lot handling discipline. In many businesses the operational goal is also to ship the oldest stock first, yet that must be enforced through processes such as date based picking, lot rotation, and storage logic. System configuration alone does not guarantee physical FIFO behavior.

How does FIFO affect financial statements when prices rise?

When purchase or production costs are increasing, FIFO usually sends older lower costs to cost of goods sold and leaves newer higher costs in ending inventory. That tends to increase reported gross margin compared with methods that expense newer costs sooner. It also means the inventory balance on the balance sheet is often closer to recent acquisition cost, which can be useful for valuation analysis.

Why is FIFO important in regulated or perishable inventory?

Older stock often carries higher risk of expiry, degradation, shelf life loss, or packaging obsolescence. FIFO rotation reduces the chance that usable stock remains buried behind newer receipts while it loses value. In regulated sectors, disciplined lot rotation also supports traceability and compliance because the organization can show how inventory age and usage sequence are controlled throughout storage and distribution.

Can FIFO be used for both raw materials and finished goods?

Yes. FIFO can be applied across raw materials, components, work in process cost layers where appropriate, and finished goods inventory. The exact operational implementation differs by product type and system design, but the principle remains the same: the earliest cost or receipt layer is relieved first. Businesses often combine the costing logic with physical stock rotation rules to keep accounting and warehouse behavior aligned.