What is Variable Cost?

S7-SA7-0089

Grade Level:

Class 12

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

Definition

What is it?

Variable cost is an expense that changes directly with the amount of goods or services a business produces. The more you produce, the higher the total variable cost, and the less you produce, the lower it is.

Simple Example

Quick Example

Imagine a chai stall owner. The cost of milk, sugar, and tea leaves increases if they make more cups of chai. If they make only 10 cups, they buy less ingredients; if they make 100 cups, they buy much more. This changing cost for ingredients is a variable cost.

Worked Example

Step-by-Step

Let's say a bakery makes delicious samosas. Each samosa needs 10 rupees worth of ingredients (flour, potatoes, oil, spices). This 10 rupees is the variable cost per samosa.

--- If the bakery makes 50 samosas:
Total Variable Cost = Number of Samosas x Variable Cost per Samosa
Total Variable Cost = 50 x 10 rupees = 500 rupees

--- If the bakery makes 100 samosas:
Total Variable Cost = 100 x 10 rupees = 1000 rupees

--- If the bakery makes 0 samosas:
Total Variable Cost = 0 x 10 rupees = 0 rupees

Answer: The total variable cost changes from 500 rupees to 1000 rupees (or 0) depending on how many samosas are made.

Why It Matters

Understanding variable costs helps businesses decide how much to produce and what price to set. In fields like AI/ML, it helps optimize resource usage for computing tasks. Entrepreneurs in FinTech or EV manufacturing use this to plan budgets and predict profits, impacting careers from data scientists to business strategists.

Common Mistakes

MISTAKE: Confusing variable cost with fixed cost. | CORRECTION: Variable costs change with production volume, while fixed costs (like rent) remain the same regardless of how much is produced.

MISTAKE: Thinking variable cost per unit also changes. | CORRECTION: The total variable cost changes, but the variable cost per unit (e.g., cost of ingredients for one samosa) usually stays constant.

MISTAKE: Not including all production-related expenses as variable costs. | CORRECTION: Remember to include all costs directly tied to producing each additional unit, like raw materials, direct labour, and packaging.

Practice Questions

Try It Yourself

QUESTION: A t-shirt printing business spends 50 rupees on ink and fabric for each t-shirt. If they print 20 t-shirts, what is the total variable cost? | ANSWER: 1000 rupees

QUESTION: A mobile app company charges for premium features. For every new user who subscribes to the premium feature, the company incurs a server cost of 5 rupees. If 500 new users subscribe this month, what is the total variable cost for server usage? | ANSWER: 2500 rupees

QUESTION: A small factory makes 100 cricket bats. The wood for each bat costs 300 rupees, and the labour to make one bat costs 150 rupees. What is the total variable cost for making 100 bats? | ANSWER: 45,000 rupees (300 + 150 = 450 per bat; 450 * 100 = 45,000)

MCQ

Quick Quiz

Which of the following is an example of a variable cost for a company that manufactures mobile phones?

Rent of the factory building

Salaries of the factory manager

Cost of microchips and screens for each phone

Insurance premium for the factory

The Correct Answer Is:

The cost of microchips and screens changes directly with the number of phones produced. Rent, manager salaries, and insurance are fixed costs that don't change with production volume.

Real World Connection

In the Real World

Think about online food delivery apps like Zomato or Swiggy. The fuel cost for each delivery rider changes based on the number of orders they deliver. More deliveries mean more fuel expense, making fuel a variable cost for the company in terms of per-delivery operations.

Key Vocabulary

Key Terms

PRODUCTION VOLUME: The total quantity of goods or services produced | FIXED COST: An expense that does not change with the level of production | PER UNIT COST: The cost associated with producing one single item | RAW MATERIALS: Basic substances used in the production of goods

What's Next

What to Learn Next

Now that you understand variable costs, you should learn about 'Fixed Costs'. Knowing both fixed and variable costs will help you calculate total costs and understand how businesses make pricing decisions and manage their finances. Keep up the great work!