Management Accounting · Applications of Marginal Costing in Short Term Decision Making

Sales Mix, Break-Even and Profit Planning Decisions

Updated 10 October 2026 · Fact-checked

These questions use marginal costing to find the sales level where profit is zero, how far sales can fall before a loss, and what sales give a target profit. With several products, fix the sales mix, find the weighted average contribution, then divide fixed costs (plus target profit) by it.

Understand Sales Mix, Break-Even and Profit Planning Decisions

Marginal costing splits costs into variable and fixed. Contribution is sales minus variable cost. Fixed costs are recovered from contribution. Profit appears only after total contribution exceeds fixed costs. This one idea drives every question in this topic.

The break-even point (BEP) is the sales level where total contribution equals fixed costs, so profit is zero. The margin of safety (MoS) is actual (or budgeted) sales minus break-even sales. It tells you how much sales can fall before you make a loss.

With one product, BEP is simple. With many products, each product has a different contribution, so the answer depends on the sales mix, the proportion in which products are sold. You treat the mix as a single "pack" or composite product. Its contribution and sales value give a weighted average contribution per unit or a composite P/V ratio.

If the mix shifts toward products with a higher contribution per rupee of sales, the overall P/V ratio rises, break-even falls and profit rises, even if total sales do not change. A shift toward low-contribution products does the opposite. This is why management watches the mix.

Target profit planning turns the question around. You are given the profit wanted. You treat it like an extra fixed cost: required contribution = fixed costs + target profit. Divide by contribution per unit (or P/V ratio) to get the units (or sales value) needed.

Key rules to remember

Contribution: Contribution = Sales − Variable cost; Per unit: selling price − variable cost per unit.
P/V ratio: P/V ratio = Contribution ÷ Sales × 100; Equals change in profit ÷ change in sales when fixed costs stay constant.
Break-even point (units): BEP (units) = Fixed costs ÷ Contribution per unit; Use for a single product or per mix pack.
Break-even point (sales value): BEP (₹) = Fixed costs ÷ P/V ratio; Use composite P/V ratio for several products in a given mix.
Margin of safety: MoS = Actual sales − Break-even sales = Profit ÷ P/V ratio; MoS ratio = MoS ÷ Actual sales × 100.
Target profit: Required sales (₹) = (Fixed costs + Target profit) ÷ P/V ratio; In units: (Fixed costs + Target profit) ÷ Contribution per unit. For a profit after tax, convert to before-tax profit first.
Composite P/V ratio: Composite P/V = Total contribution of mix ÷ Total sales of mix × 100; Changes whenever the mix changes.
Multi-product BEP: BEP packs = Fixed costs ÷ Contribution per pack; product BEP = packs × units of that product in the pack; Valid only if the stated mix is held constant.

How to solve Sales Mix, Break-Even and Profit Planning Decisions questions

Use this order for any break-even, margin of safety, mix or target profit question.

1Classify costs as variable or fixed. Split semi-variable costs if needed.
2Find contribution per unit and P/V ratio for each product.
3Fix the sales mix. If it is given in units, build a pack; if in sales value, work in rupees.
4Compute total contribution of the pack or mix and the composite P/V ratio.
5Apply the formula: BEP = fixed costs ÷ contribution (or P/V ratio). For target profit, add the profit to fixed costs first.
6Split the result among products using the mix.
7Compute margin of safety and profit if asked: profit = total contribution − fixed costs.
8State the result with a one-line interpretation, such as how mix change affects BEP and profit.

Quickest way: Pack method and P/V shortcut

When to use it: Use when the mix is given as a ratio of units or sales and you must find BEP or target sales fast.

Write one pack: units of each product in the ratio.
Add pack contribution and pack sales in two lines.
Divide fixed costs (plus target profit) by pack contribution to get packs.
Multiply packs by pack units to get each product's units.
Check: packs × pack contribution − fixed costs should equal the target profit (or zero for BEP).
For MoS use profit ÷ P/V ratio as a cross-check.

Common mistakes in Sales Mix, Break-Even and Profit Planning Decisions

Dividing fixed costs by the simple average of contribution per unit across products.
It looks quicker and ignores the mix.
Fix: Always weight contribution by the sales mix, using a pack or composite P/V ratio.
Using the old mix after the mix has changed.
Students reuse the earlier P/V ratio.
Fix: Recalculate total contribution and the composite P/V ratio for the new mix every time.
Not adding target profit to fixed costs.
Students treat BEP and target sales as the same formula.
Fix: Required contribution = fixed costs + target profit. Then divide.
Finding MoS from break-even units but giving the answer in rupees (or the reverse).
Mixing units and sales value across steps.
Fix: Convert to the same unit before subtracting. Label every answer with units or ₹.
Including fixed costs in variable cost per unit, or treating fixed cost as changing with the mix.
Absorption costing habits.
Fix: Use only variable costs for contribution. Fixed costs stay constant in total unless the question says they change.
Reporting the product break-even without stating the mix assumption.
Students give numbers but not the condition.
Fix: Write that break-even for each product holds only if the stated mix is maintained.

Worked examples

Example 1

Delta Ltd sells products A and B in the ratio 3:2 (units). A: selling price ₹100, variable cost ₹60 per unit. B: selling price ₹150, variable cost ₹100 per unit. Fixed costs are ₹4,40,000. Find (a) break-even units and sales of each product, (b) profit and margin of safety if 7,500 units of A and 5,000 units of B are sold, and (c) units of each product needed for a profit of ₹2,20,000.

Show the solution

Contribution per unit: A = 100 − 60 = ₹40; B = 150 − 100 = ₹50.
One pack = 3 units of A + 2 units of B. Pack contribution = 3 × 40 + 2 × 50 = 120 + 100 = ₹220.
Pack sales = 3 × 100 + 2 × 150 = 300 + 300 = ₹600. Composite P/V ratio = 220 ÷ 600 = 36.67%.
(a) Break-even packs = 4,40,000 ÷ 220 = 2,000 packs. A = 2,000 × 3 = 6,000 units; B = 2,000 × 2 = 4,000 units. Break-even sales = 2,000 × 600 = ₹12,00,000 (A ₹6,00,000 + B ₹6,00,000).
(b) Actual packs = 7,500 ÷ 3 = 2,500. Total contribution = 2,500 × 220 = ₹5,50,000. Profit = 5,50,000 − 4,40,000 = ₹1,10,000.
Actual sales = 2,500 × 600 = ₹15,00,000. Margin of safety = 15,00,000 − 12,00,000 = ₹3,00,000, which is 20% of actual sales. Check: 1,10,000 ÷ 36.67% = ₹3,00,000.
(c) Required contribution = 4,40,000 + 2,20,000 = ₹6,60,000. Packs = 6,60,000 ÷ 220 = 3,000. A = 9,000 units; B = 6,000 units.

Answer: (a) Break-even: A 6,000 units, B 4,000 units, total sales ₹12,00,000. (b) Profit ₹1,10,000; margin of safety ₹3,00,000 (20%). (c) For ₹2,20,000 profit: A 9,000 units and B 6,000 units, in the same 3:2 mix.

Example 2

Omega Ltd sells products X and Y. Sales are ₹10,00,000 of X (P/V ratio 40%) and ₹5,00,000 of Y (P/V ratio 20%). Fixed costs are ₹3,00,000. Find the profit, break-even sales and margin of safety. Then find the effect on these if the mix changes to ₹5,00,000 of X and ₹10,00,000 of Y, with total sales unchanged.

Show the solution

Original contribution: X = 10,00,000 × 40% = ₹4,00,000; Y = 5,00,000 × 20% = ₹1,00,000. Total = ₹5,00,000.
Total sales = ₹15,00,000. Composite P/V = 5,00,000 ÷ 15,00,000 = 33.33%.
Profit = 5,00,000 − 3,00,000 = ₹2,00,000.
Break-even sales = 3,00,000 ÷ 33.33% = ₹9,00,000. Margin of safety = 15,00,000 − 9,00,000 = ₹6,00,000, which is 40% of sales.
New mix contribution: X = 5,00,000 × 40% = ₹2,00,000; Y = 10,00,000 × 20% = ₹2,00,000. Total = ₹4,00,000.
New composite P/V = 4,00,000 ÷ 15,00,000 = 26.67%. New profit = 4,00,000 − 3,00,000 = ₹1,00,000.
New break-even sales = 3,00,000 ÷ 26.67% = ₹11,25,000. New margin of safety = 15,00,000 − 11,25,000 = ₹3,75,000, which is 25% of sales.

Answer: Original: profit ₹2,00,000; break-even sales ₹9,00,000; margin of safety ₹6,00,000 (40%). New mix: profit ₹1,00,000; break-even sales ₹11,25,000; margin of safety ₹3,75,000 (25%). Shifting sales toward the lower P/V product Y cuts profit by ₹1,00,000 and raises break-even.

Exam tips

Write the pack or composite P/V working in a clear block. Step marks are given even if the final figure is wrong.
Always state the mix assumption when giving product-wise break-even.
In MCQs, check whether the question asks for units or rupees, and whether fixed cost or target profit is included.
For mix-change questions, compare old and new results in a short line and say which mix is better and why.
Verify with profit = contribution − fixed costs. It takes ten seconds and catches arithmetic slips.

Practice questions from Applications of Marginal Costing in Short Term Decision Making

Sales Mix, Break-Even and Profit Planning Decisions in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Sales Mix, Break-Even and Profit Planning Decisions: frequently asked questions

How do you find break-even for more than one product?

Fix the sales mix, then compute total contribution and sales for one pack of the mix. Divide fixed costs by pack contribution to get packs, or by the composite P/V ratio to get break-even sales. Split the result using the mix.

What is the margin of safety formula?

Margin of safety = actual sales − break-even sales. It also equals profit ÷ P/V ratio. Express it as a percentage of actual sales to compare periods or products.

How do you calculate target profit using marginal costing?

Add the target profit to fixed costs to get the required contribution. Divide it by contribution per unit for units, or by the P/V ratio for sales value.

How does a change in sales mix affect profit?

If sales shift toward products with a higher P/V ratio, total contribution and profit rise even if total sales stay the same. A shift toward lower P/V products reduces profit and raises break-even sales.