ACCA Applied Knowledge · Management Accounting
Absorption and Marginal Costing for ACCA Management Accounting
Absorption costing includes a share of fixed production overheads in each unit's cost. Marginal costing includes only variable costs and treats fixed costs as a period expense. Profit differs when inventory levels change. To solve questions, calculate the overhead rate, value inventory under each method, then reconcile the profit.
What this chapter covers
This chapter is about two ways of costing a product and measuring profit. Absorption costing adds a fair share of fixed production overheads to each unit using an overhead absorption rate. Marginal costing only charges variable costs to units. Fixed costs are written off in full in the period they are incurred.
The chapter has a clear flow. You first learn how to build an absorption rate and apply it. Then you see what happens when the overhead absorbed differs from the overhead actually incurred. Next you learn marginal costing and contribution. Finally you compare the two methods, reconcile their profits and judge when each is useful.
In the Management Accounting exam, this chapter feeds directly into later work. Contribution is the base for break-even analysis and short-term decisions. Unit costs and inventory valuation link to cost accounting and to budgeting and standard costing in Section B. Expect Section A objective test questions here, such as number entry for a rate or a profit difference, and multiple choice on which method suits a situation.
This chapter is worth your effort because the calculations are short, rule-based and repeatable, so you can score reliably once the method is clear. The same ideas also appear inside other chapters: contribution drives break-even and decision questions, and overhead rates feed costing and budgeting. Every exam question is compulsory and the pass mark is 50%, so reliable marks on a predictable topic matter. Learning this chapter well also makes later chapters easier.
Absorption and marginal costing: topics in the order to study them
- 1Absorption Costing and Overhead Absorption RatesStart here because it builds the unit cost and the overhead rate that the rest of the chapter depends on.
- 2Over and Under Absorption of OverheadsIt follows directly, since it compares the overhead absorbed using your rate with the actual overhead incurred.
- 3Marginal Costing and ContributionLearn this next as a separate method, with variable costs only and fixed costs treated as a period cost.
- 4Absorption vs Marginal Costing Profit ReconciliationYou need both methods in hand before you can explain why their profits differ.
- 5Advantages and Limitations of Each Costing MethodFinish with this theory topic, which is easier once you have seen the numbers behind each method.
How to prepare Absorption and marginal costing
Work from calculation to comparison to theory. Short daily sessions on your phone are enough if you practise numbers on paper.
- Learn the absorption rate formula: budgeted overhead ÷ budgeted activity level (for example labour hours or machine hours). Practise until you can do it without notes.
- Practise over and under absorption: absorbed overhead = rate × actual activity. Compare it with actual overhead. If absorbed is less than actual, overhead is under absorbed.
- Build unit cost and profit statements under marginal costing: sales − variable costs = contribution; contribution − fixed costs = profit.
- Do reconciliation questions. Check the change in inventory units first. Profit difference = change in inventory units × fixed overhead absorbed per unit.
- Learn the advantages and limitations as short pairs. Link each point to a situation, such as inventory build-up or short-term decisions.
- Finish with timed objective test sets. Practise number entry, where you must key in a precise figure, and multiple response, where you must select the stated number of options.
Common mistakes in Absorption and marginal costing
Using actual figures instead of budgeted figures to set the absorption rate.
Fix: Use budgeted overhead and budgeted activity for the rate. Use actual activity only when calculating the overhead absorbed.
Getting the direction of over or under absorption wrong.
Fix: Always write absorbed minus actual. If absorbed is lower, the overhead is under absorbed.
Including fixed overhead in inventory valuation under marginal costing.
Fix: Value inventory only at variable production cost under marginal costing.
Using sales units instead of the change in inventory units in a reconciliation.
Fix: Calculate opening and closing inventory, then use only the change in inventory units.
Stating which method gives higher profit without checking inventory movement.
Fix: Look at the inventory movement. Rising inventory means absorption costing profit is higher, while falling inventory means marginal costing profit is higher.
Deducting variable selling costs wrongly when finding contribution.
Fix: Contribution is sales less all variable costs, including variable selling and distribution costs.
Last-day revision: Absorption and marginal costing
- Absorption costing includes fixed production overheads in unit cost. Marginal costing does not.
- Overhead absorption rate = budgeted overhead ÷ budgeted activity.
- Absorbed overhead = absorption rate × actual activity.
- Under absorption: absorbed overhead is less than actual overhead. Profit is reduced by the adjustment.
- Over absorption: absorbed overhead is more than actual overhead. Profit is increased by the adjustment.
- Contribution = sales − variable costs.
- Marginal costing profit = total contribution − total fixed costs for the period.
- Inventory is valued at variable production cost under marginal costing.
- If production is more than sales, inventory rises and absorption costing profit is higher.
- If sales are more than production, inventory falls and marginal costing profit is higher.
- If inventory does not change, both methods give the same profit.
- Profit difference = change in inventory units × fixed overhead per unit.
Absorption and marginal costing practice questions
- Tamsin Ltd had opening inventory of 2,000 units and closing inventory of 5,000 units. Fixed production overhead is absorbed at $6 per unit a…
- Brindle Co absorbs production overheads on a machine hour basis. Budgeted overheads were $450,000 for 90,000 machine hours. Actual overheads…
- Harlow Ltd budgets fixed production overheads of $240,000 and 30,000 direct labour hours for the period. Actual direct labour hours worked w…
- Delta Ltd produced 10,000 units and sold 8,000 units in a period. Fixed production overhead was $50,000 for the period, budgeted output was …
- Which statement correctly explains why absorption costing and marginal costing profits differ when production and sales volumes differ?
- Kestrel Co sold 6,000 units in a period at $25 per unit. Variable costs were $15 per unit and fixed costs were $42,000. What was the profit …
- Which of the following is the main reason a business would use a direct labour hour absorption rate rather than a rate per unit of output?
- Harlow Ltd budgets production overheads of $240,000 and 30,000 direct labour hours for the period. Actual overheads were $252,000 and actual…
Absorption and 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.
Absorption and marginal costing: frequently asked questions
What is the main difference between absorption and marginal costing?
Absorption costing treats fixed production overheads as part of the product cost. Marginal costing treats them as a cost of the period. This changes the value of inventory and the profit reported when inventory levels move.
Why do the two methods give different profits?
The difference comes from fixed production overheads held in inventory. Under absorption costing, some fixed overhead is carried forward in closing inventory. Under marginal costing, all of it is charged in the period.
Do I need to learn theory as well as calculations?
Yes. The exam is computer-based and uses objective test questions, so you may be asked to choose valid advantages or limitations of a method. Learn short points and link them to real situations.
How do I answer a number entry question on overhead rates?
Work out the answer on paper, then check which units the question asks for, such as dollars per hour. Keep to the decimal places the question requires before you enter your answer.