Management Accounting · Absorption and marginal costing

Marginal Costing and Contribution Explained for ACCA MA

Updated 11 October 2026 · Fact-checked

Marginal costing treats only variable costs as product costs. Contribution is sales minus variable costs, shown per unit or in total. Fixed costs are not put into inventory. They are charged in full as a period cost. Profit equals total contribution minus total fixed costs for the period.

Understand Marginal Costing and Contribution

Marginal costing is a way of costing products where only variable costs are included in the cost of a unit. Direct materials, direct labour (if variable), variable production overheads and variable selling costs all count. Fixed costs do not.

Why leave fixed costs out? They do not change with output in the short run. Rent is the same whether you make 100 units or 1,000. So they are not caused by making one more unit. Marginal costing treats them as a period cost: you charge the whole amount against profit in the period it is incurred.

Contribution is what each unit adds towards covering fixed costs and then making profit. Contribution per unit = selling price per unit minus variable cost per unit. Once total contribution has covered fixed costs, every extra dollar of contribution is profit.

Because fixed costs are never carried in inventory, closing inventory is valued at variable production cost only. This is the key difference from absorption costing and the reason profits differ when inventory levels change. If production equals sales, the two methods give the same profit.

The income statement layout reflects this. You show sales, deduct variable costs to reach contribution, then deduct fixed costs to reach profit. Fixed costs appear as one block, not spread over units.

Key formulas to remember

Contribution per unit: Contribution per unit = selling price per unit − variable cost per unit; Variable cost includes variable production and variable selling and administration costs.
Total contribution: Total contribution = sales revenue − total variable costs = contribution per unit × units sold; Use units sold, not units produced.
Marginal costing profit: Profit = total contribution − total fixed costs; All fixed costs for the period, production and non-production, are deducted.
Inventory valuation: Inventory value = units × variable production cost per unit; No fixed overhead is included. Variable selling costs are not part of inventory.
Cost of sales (marginal): Opening inventory + variable production cost of units produced − closing inventory; Add variable selling costs separately, based on units sold.

How to solve Marginal Costing and Contribution questions

Use this order for any marginal costing question. It keeps variable and fixed costs apart and stops you mixing units produced with units sold.

1Read the question and list each cost. Mark each one as variable or fixed, and as production or non-production.
2Note units produced, units sold and any opening or closing inventory.
3Work out variable production cost per unit and use it to value inventory.
4Calculate contribution per unit: selling price minus all variable costs, including variable selling costs.
5Multiply contribution per unit by units sold to get total contribution.
6Deduct total fixed costs for the period, in full, to get profit.
7Check that no fixed cost is in inventory and that variable selling costs use units sold.
8Check that the answer matches what was asked: per unit, total contribution or profit.

Quickest way: Contribution first, then deduct fixed costs

When to use it: Use this for number entry or multiple choice questions that ask for profit or contribution and give no need to show a full statement.

Find contribution per unit: price minus every variable cost.
Multiply by units sold.
Subtract total fixed costs.
If the question needs inventory, value it at variable production cost only.
Skip cost of sales workings unless inventory values are requested.

Common mistakes in Marginal Costing and Contribution

Including fixed production overhead in inventory valuation
Students are used to absorption costing, where inventory carries fixed overhead.
Fix: In marginal costing, value inventory at variable production cost only. Charge fixed costs to the period.
Using units produced instead of units sold to calculate contribution
Production figures are often given first and look important.
Fix: Contribution comes from sales. Always multiply contribution per unit by units sold.
Leaving variable selling costs out of contribution per unit
Students think only production costs matter for product cost.
Fix: Deduct all variable costs, including sales commission and variable distribution, when finding contribution. Just do not include them in inventory value.
Deducting fixed costs per unit instead of in total
Absorption costing uses a rate per unit, so students copy that habit.
Fix: Show fixed costs as one total amount for the period. No fixed cost per unit is needed.
Confusing contribution with profit
Both come from sales minus costs, so they look alike.
Fix: Contribution is before fixed costs. Profit is contribution minus fixed costs.
Treating all semi-variable or stepped costs as variable
The question wording is skimmed.
Fix: Split mixed costs into fixed and variable parts first. Only the variable part goes into contribution.

Worked examples

Example 1

A company sells a product for $20 per unit. Variable production cost is $8 per unit and variable selling cost is $2 per unit. Fixed costs for the period are $30,000. The company sold 5,000 units. Calculate the contribution per unit and the profit under marginal costing.

Show the solution

Total variable cost per unit = $8 + $2 = $10.
Contribution per unit = $20 − $10 = $10.
Total contribution = $10 × 5,000 = $50,000.
Profit = $50,000 − $30,000 = $20,000.

Answer: Contribution per unit is $10 and profit is $20,000.

Example 2

In a period, a company produced 6,000 units and sold 5,000 units. There was no opening inventory. Selling price is $15 per unit. Variable production cost is $6 per unit. Variable selling cost is $1 per unit sold. Fixed production overheads are $12,000 and fixed administration costs are $8,000. Calculate the marginal costing profit and the closing inventory value.

Show the solution

Contribution per unit = $15 − $6 − $1 = $8.
Total contribution = $8 × 5,000 = $40,000.
Total fixed costs = $12,000 + $8,000 = $20,000.
Profit = $40,000 − $20,000 = $20,000.
Closing inventory = 6,000 − 5,000 = 1,000 units.
Inventory value = 1,000 × $6 = $6,000. Fixed overhead and selling costs are excluded.

Answer: Profit is $20,000 and closing inventory is valued at $6,000.

Exam tips

Read what the question asks for: contribution per unit, total contribution or profit. Each needs a different final step.
Check whether a cost is variable or fixed before using it. Watch for words like per unit, per hour and per month.
Include variable selling costs in contribution, but exclude them from inventory value.
In multiple response questions, test each statement against one rule: only variable costs are product costs and fixed costs are period costs.
If production and sales differ, expect the question to link to profit reconciliation with absorption costing.

Practice questions from Absorption and marginal costing

Marginal Costing and Contribution 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 and Contribution: frequently asked questions

What is contribution in marginal costing?

Contribution is sales revenue minus variable costs. It shows how much is available to cover fixed costs and then provide profit. You can state it per unit or in total.

How do I calculate contribution per unit in ACCA MA?

Take the selling price per unit and subtract all variable costs per unit. Include variable production costs and any variable selling costs. Fixed costs are never part of this calculation.

Why are fixed costs treated as period costs?

Fixed costs do not change with output in the short run, so they are not caused by producing a unit. They are charged in full against profit in the period they are incurred. They are not carried forward in inventory.

What is the format of a marginal costing income statement?

Show sales, then deduct variable costs to get contribution. Then deduct total fixed costs to get profit. Variable cost of sales is adjusted for opening and closing inventory at variable cost.