What is Weighted Average Method? | Simple Explanation for Class 12

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What is Weighted Average Method (Inventory Valuation)?

Grade Level:

Class 12

AI/ML, Physics, Biotechnology, FinTech, EVs, Space Technology, Climate Science, Blockchain, Medicine, Engineering, Law, Economics

Definition

What is it?

The Weighted Average Method (Inventory Valuation) is a way to calculate the average cost of all items in your stock. It helps businesses figure out the cost of goods sold and the value of remaining inventory by considering both the quantity and the price of each purchase.

Simple Example

Quick Example

Imagine you buy different types of mangoes for your shop. First, you buy 10 kg of Alphonso for ₹100/kg. Later, you buy 20 kg of Kesar for ₹80/kg. The Weighted Average Method helps you find the 'average' cost per kg for all your mangoes, taking into account you bought more Kesar than Alphonso.

Worked Example

Step-by-Step

Let's say a mobile phone shop has the following purchases of a specific phone model:
1. On Jan 5: Bought 10 phones at ₹10,000 each.
2. On Jan 15: Bought 20 phones at ₹11,000 each.
3. On Jan 25: Bought 5 phones at ₹12,000 each.

Now, let's calculate the weighted average cost per phone:

Step 1: Calculate the total cost for each purchase.
Purchase 1: 10 phones * ₹10,000 = ₹100,000
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Purchase 2: 20 phones * ₹11,000 = ₹220,000
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Purchase 3: 5 phones * ₹12,000 = ₹60,000
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Step 2: Calculate the total cost of all phones.
Total Cost = ₹100,000 + ₹220,000 + ₹60,000 = ₹380,000
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Step 3: Calculate the total number of phones purchased.
Total Quantity = 10 + 20 + 5 = 35 phones
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Step 4: Calculate the Weighted Average Cost per phone.
Weighted Average Cost = Total Cost / Total Quantity
Weighted Average Cost = ₹380,000 / 35 phones = ₹10,857.14 (approximately)
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So, the weighted average cost per phone is approximately ₹10,857.14.

Why It Matters

This method is crucial for businesses to accurately price their products and manage their finances. In FinTech, it helps banks and investment firms value assets, and in supply chain management for EVs or other products, it optimizes inventory costs. Understanding this can open doors to careers in finance, logistics, and even data analysis for companies.

Common Mistakes

MISTAKE: Simply averaging the prices without considering quantities (e.g., (10000+11000+12000)/3). | CORRECTION: Always multiply each price by its respective quantity to get the total cost for that batch, then sum all total costs and divide by the total quantity.

MISTAKE: Forgetting to include all purchases when calculating the total cost or total quantity. | CORRECTION: Double-check that every single purchase and its corresponding quantity and price are included in your calculations.

MISTAKE: Mixing up the Weighted Average Method with other inventory valuation methods like FIFO (First-In, First-Out) or LIFO (Last-In, First-Out). | CORRECTION: Remember that Weighted Average focuses on finding a single average cost for all units, not tracking individual unit costs based on purchase order.

Practice Questions

Try It Yourself

QUESTION: A small kirana store bought rice: 50 kg at ₹40/kg and then 100 kg at ₹45/kg. What is the weighted average cost per kg of rice? | ANSWER: ₹43.33/kg

QUESTION: A stationery shop purchased pens: Batch A - 200 pens at ₹8 each, Batch B - 150 pens at ₹10 each, Batch C - 50 pens at ₹7 each. Calculate the weighted average cost per pen. | ANSWER: ₹8.625 per pen

QUESTION: A bookstore bought 100 copies of a textbook for ₹300 each. Later, they bought another 150 copies for ₹320 each. If they sold 80 copies, what would be the cost of goods sold using the weighted average method? | ANSWER: ₹24,960

MCQ

Quick Quiz

Which of the following is the primary purpose of the Weighted Average Method in inventory valuation?

To always value inventory at its lowest purchase price.

To assign an average cost to all units of inventory, considering their quantities and prices.

To value inventory based on the most recent purchase price.

To separate the cost of new inventory from old inventory.

The Correct Answer Is:

The Weighted Average Method calculates a single average cost for all inventory units by weighting the cost of each purchase by its quantity. Options A, C, and D describe other inventory valuation approaches or misconceptions.

Real World Connection

In the Real World

Think about a popular online grocery app like BigBasket or Zepto. They receive thousands of products daily at varying prices from different suppliers. To calculate the cost of the vegetables or fruits they sell and the value of their remaining stock, they might use the Weighted Average Method. This helps them manage their finances and set fair selling prices for customers across India.

Key Vocabulary

Key Terms

INVENTORY: Goods a business holds for sale | VALUATION: The process of determining the monetary value of an asset | COST OF GOODS SOLD: The direct costs attributable to the production of the goods sold by a company | AVERAGE: A central or typical value in a set of data | QUANTITY: The amount or number of a material or item

What's Next

What to Learn Next

Now that you understand Weighted Average, you should explore other inventory valuation methods like FIFO (First-In, First-Out) and LIFO (Last-In, First-Out). Comparing these will show you how different methods can impact a business's financial statements and profits!