Inventory Management

What is Weighted Average Cost Method?

An inventory valuation method that calculates the average cost per unit by dividing total cost of goods available by total units available, updating with each new purchase.

How It Works

The Weighted Average Cost (WAC) method smooths out price fluctuations by averaging the cost of all units available for sale. Each time new inventory is purchased, the average cost is recalculated. This method is permitted under both Indian Accounting Standards (Ind AS 2) and IFRS. It falls between FIFO (which may overstate profits during inflation) and LIFO (not permitted in India). WAC is particularly suitable for businesses dealing in homogeneous goods where individual units are indistinguishable (e.g., fuel, chemicals, grains).

Formula

Weighted Average Cost per Unit = Total Cost of Goods Available ÷ Total Units Available

Real-World Example

Opening stock: 200 units @ ₹50 = ₹10,000. Purchase 1: 300 units @ ₹55 = ₹16,500. Purchase 2: 100 units @ ₹60 = ₹6,000. Total: 600 units, ₹32,500. WAC = ₹32,500 ÷ 600 = ₹54.17/unit. If 400 sold: COGS = 400 × ₹54.17 = ₹21,668.

Why It Matters

1

Ensures accurate financial reporting and record-keeping

2

Helps maintain regulatory and tax compliance

3

Enables better-informed business decisions

4

Improves operational efficiency and cash flow management

Frequently Asked Questions

When should I use weighted average vs FIFO?

Use WAC when: goods are homogeneous and interchangeable, you want stable COGS figures, or tracking specific batches is impractical. Use FIFO when: goods are perishable, batch tracking is important, or you want ending inventory to reflect current market prices.

Is weighted average cost method accepted for tax purposes in India?

Yes. Indian Accounting Standards (Ind AS 2) permits both FIFO and Weighted Average Cost. For income tax purposes, either method is acceptable as long as it's consistently applied. LIFO is NOT permitted.

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