CA Intermediate · Cost and Management Accounting
Marginal Costing for CA Intermediate: Chapter Guide
Marginal costing treats only variable costs as product costs and charges fixed costs to the period. You solve it by finding contribution (sales − variable cost), then using P/V ratio, break-even point and margin of safety for profit and decision questions. Always show formula, working and interpretation.
What this chapter covers
Marginal costing is a technique where only variable costs are charged to units produced. Fixed costs are written off in the period they are incurred. The key figure is contribution, which is sales minus variable cost. Profit is contribution minus fixed cost.
The chapter builds in layers. You start with cost behaviour and the marginal costing statement. Then you compare it with absorption costing and reconcile the profit difference. After that come CVP analysis, P/V ratio and break-even analysis. The last layer applies all of it to decisions such as make or buy, accept or reject a special order, and product mix with a limiting factor.
This chapter connects to the rest of Paper 4. It uses the cost classification and cost sheet you already know. It also feeds budgeting, standard costing and the decision parts of the paper. In Financial Management, the same contribution logic appears in leverage. If you master this chapter, many other numerical questions become easier.
Marginal costing is formula-driven and has a clear method, so it is a scoring chapter if you practise. It gives you both MCQs, which are quick to solve once the ratios are clear, and written problems where step marks are available even if your final answer is off. The same ideas return in decision-making questions elsewhere in the paper, so the effort pays back more than once. Careful practice also improves your speed in the numerical portion of Paper 4.
Marginal Costing: topics in the order to study them
- 1Marginal Costing Concepts and Cost BehaviourEverything depends on separating fixed, variable and semi-variable costs and understanding contribution, so start here.
- 2Absorption vs Marginal Costing and Profit ReconciliationIt uses the concepts above and shows why profits differ when opening and closing stock differ.
- 3Cost-Volume-Profit Analysis and P/V RatioOnce you can build a marginal statement, you can derive P/V ratio and link sales, cost and profit.
- 4Break-Even Analysis and Break-Even ChartBreak-even point, margin of safety and charts are direct applications of contribution and P/V ratio.
- 5Marginal Costing in Decision MakingThis is the final application and needs all earlier tools, so study it last.
How to prepare Marginal Costing
Prepare this chapter by building the logic first and then practising a graded set of problems. Keep a one-page formula sheet and add to it as you go.
- Classify costs as fixed, variable or semi-variable. Split a semi-variable cost using the high-low method or from two activity levels.
- Practise writing a marginal costing statement: sales, variable cost, contribution, fixed cost, profit. Use this layout for every problem.
- Learn the formulas: Contribution = Sales − Variable cost; P/V ratio = Contribution ÷ Sales × 100; BEP (units) = Fixed cost ÷ Contribution per unit; BEP (sales) = Fixed cost ÷ P/V ratio; Margin of safety = Actual sales − Break-even sales.
- Solve reconciliation problems. Under absorption costing, the fixed cost per unit is carried in stock, so profit differs when stock changes. Then check your answer by reconciling.
- Practise decision problems by asking one question first: is there a limiting factor? If yes, rank by contribution per unit of that factor. If no, compare total contribution.
- Finish with timed mixed sets. Do MCQs first for speed, then full written problems, and write a one-line interpretation at the end of each.
Common mistakes in Marginal Costing
Treating fixed costs as part of product cost in a marginal costing statement
Fix: Take fixed costs below the contribution line as a period cost. Value stock at variable cost only.
Using the wrong denominator for P/V ratio or break-even
Fix: Write the formula first, then check that the numerator is contribution and the units match.
Reconciling profit in the wrong direction
Fix: Compute the fixed overhead in opening and closing stock. Adjust marginal profit by the difference in the fixed overhead carried in stock.
Ranking products by contribution per unit when a resource is limited
Fix: Read the data for a scarce resource. If present, calculate contribution per unit of that resource and rank by it.
Including sunk or unchanged fixed costs in a decision
Fix: Include only costs that change because of the decision, and state clearly why other costs are ignored.
Giving a number with no interpretation
Fix: Add a short conclusion, such as 'accept the order because it adds ₹X to contribution'.
Last-day revision: Marginal Costing
- Marginal cost is the variable cost of one extra unit.
- Contribution = Sales − Variable cost.
- Profit = Contribution − Fixed cost.
- P/V ratio = Contribution ÷ Sales × 100.
- BEP (sales) = Fixed cost ÷ P/V ratio.
- Margin of safety = Actual sales − Break-even sales.
- Required sales for target profit = (Fixed cost + Target profit) ÷ P/V ratio.
- Marginal costing values stock at variable cost only; absorption costing includes fixed production overhead.
- When closing stock is higher than opening stock, absorption costing profit is usually higher.
- With a limiting factor, rank products by contribution per unit of the limiting factor.
- In a special order or shutdown choice, fixed costs that do not change are irrelevant.
- Fixed cost per unit changes with volume; total fixed cost stays the same within the relevant range.
Marginal Costing practice questions
- Under marginal costing, which statement about stock valuation is correct?
- Sundaram Appliances sells two products. Product A: selling price Rs 100, variable cost Rs 60, sales mix 3 units. Product B: selling price Rs…
- Gupta Brothers make a single product. Sales are ₹10,00,000, variable costs ₹6,00,000 and fixed costs ₹3,00,000. What is the margin of safety…
- Sundaram Pens Ltd sells a pen at Rs 50 per unit. Variable cost is Rs 30 per unit and total fixed cost is Rs 2,40,000 per year. The company w…
- Rohan Plastics sells a product at ₹80 per unit. Variable cost is ₹52 per unit and fixed cost is ₹2,10,000 per period. What is the break-even…
- Hind Tools makes two products, A and B. A sells at ₹100 with variable cost ₹60; B sells at ₹80 with variable cost ₹56. Each unit of A needs …
- Ravi Auto Components makes a part with selling price ₹80, variable cost ₹50 and fixed costs ₹3,00,000. Its margin of safety is 40% of actual…
- Which of the following statements about the treatment of fixed costs under marginal costing is correct?
Marginal Costing in other exams
The same ground in other exams, if you are preparing for more than one or want another angle on it.
Marginal Costing: frequently asked questions
Is Marginal Costing important for CA Intermediate Cost and Management Accounting?
Yes. It is a core numerical chapter and its logic is reused in decision-making questions. It can appear as MCQs and as written problems.
What is the difference between marginal costing and absorption costing?
Marginal costing charges only variable costs to products and treats fixed costs as period costs. Absorption costing charges both variable and fixed production costs to products. Profits differ when opening and closing stock differ.
How do I calculate the break-even point?
Divide fixed cost by contribution per unit to get break-even units. Divide fixed cost by P/V ratio to get break-even sales value. Check that your contribution is calculated using variable cost only.
How should I answer a marginal costing question to get step marks?
Start with a clear statement of sales, variable cost, contribution and fixed cost. Show each formula and substitution, then end with a one-line conclusion. Even if one figure is wrong, you can still earn marks for the method.