Show Chapter learning objectives Upon completion of this chapter you will be able to:
1 Marginal costing The marginal cost of an item is its variable cost. The marginalproduction cost of an item is the sum of its direct materials cost,direct labour cost, direct expenses cost (if any) and variableproduction overhead cost. So as the volume of production and salesincreases total variable costs rise proportionately. Fixed costs, in contrast are cost that remain unchanged in a time period, regardless of the volume of production and sale. Marginal production cost is the part of the cost of one unit of productor service which would be avoided if that unit were not produced, orwhich would increase if one extra unit were produced.From this we can develop the following definition of marginal costing as used in management accounting: Marginal costing is the accounting system in which variable costsare charged to cost units and fixed costs of the period are written offin full against the aggregate contribution. Note that variable costs are those which change as output changes– these are treated under marginal costing as costs of the product.Fixed costs, in this system, are treated as costs of the period. Marginal costing is also the principal costing technique used indecision making. The key reason for this is that the marginal costingapproach allows management's attention to be focussed on the changeswhich result from the decision under consideration. The contribution concept The contribution concept lies at the heart of marginal costing. Contribution can be calculated as follows. Contribution = Sales price – Variable costs Illustration 1 – The concept of contributionThe following information relates to a company that makes a singleproduct, a specialist lamp, which is used in the diamond-cuttingbusiness. Fixed costs have been estimated to be $120,000 based on a production level of 1,200 lamps. Let us look at the costs and revenues involved when different volumes of lamps are sold.
Based on what we have seen above, the idea of profit is not aparticularly useful one as it depends on how many units are sold. Forthis reason, the contribution concept is frequently employed bymanagement accountants.
Buhner Ltd makes only one product, the cost card of which is: The selling price of one unit is $21. Budgeted fixed overheads are based on budgeted production of 5,000units. Opening inventory was 1,000 units and closing inventory was 4,000units. Sales during the period were 3,000 units and actual fixed production overheads incurred were $25,000. (a) Calculate the total contribution earned during the period. (b) Calculate the total profit or loss for the period. 2 Absorption costing The principles of absorption costing have been discussed in the previous chapter – Accounting for overheads. Absorption costing is a method of building up a full product cost whichadds direct costs and a proportion of production overhead costs bymeans of one or a number of overhead absorption rates.3 The effect of absorption and marginal costing on inventory valuation and profit determination Absorption and marginal costing Marginal costing values inventory at the total variable production cost of a unit of product. Absorption costing values inventory at the full production cost of a unit of product.
Absorption costing income statement In order to be able to prepare income statements under absorptioncosting, you need to be able to complete the following proforma. Absorption costing income statement
Marginal costing income statement In order to be able to prepare income statements under marginal costing, you need to be able to complete the following proforma. Marginal costing income statement
A company commenced business on 1 March making one product only, the cost card of which is as follows: The fixed production overhead figure has been calculated on thebasis of a budgeted normal output of 36,000 units per annum. The fixedproduction overhead incurred in March was $15,000 each month. Selling, distribution and administration expenses are: The selling price per unit is $35 and the number of units produced and sold were: Prepare the absorption costing and marginal costing income statements for March. Absorption costing income statement – March Marginal costing income statement – March SolutionSolution Absorption costing income statement – March Workings (W1) (W2) Marginal costing income statement - March Test your understanding 2Duo Ltd makes and sells two products, Alpha and Beta. The following information is available for period 3: Fixed production overheads for the period were $105,000 and fixed administration overheads were $27,000. Required: (a) Prepare an income statement for period 3 based on marginal costing principles. (b) Prepare an income statement for period 3 based on absorption costing principles. Reconciling profits reported under the different methods When inventory levels increase or decrease during a period then profits differ under absorption and marginal costing.
This is because fixed overheads held in closing inventory arecarried forward (thereby reducing cost of sales) to the next accountingperiod instead of being written off in the current accounting period (asa period cost, as in marginal costing).
This is because fixed overhead brought forward in openinginventory is released, thereby increasing cost of sales and reducingprofits.
A company commenced business on 1 March making one product only, the cost card of which is as follows.
The number of units produced and sold was as follows. Closing inventory at the end of March is the difference between thenumber of units produced and the number of units sold, i.e. 500 units(2,000 – 1,500).
In an exam question you may be told the profit under eithermarginal or absorption costing and be asked to calculate the alternativeprofit for the information provided. There is a short cut to reconciling the profits: Test your understanding 3(a) In a period where opening inventorywas 5,000 units and closing inventory was 3,000 units, a company had aprofit of $92,000 using absorption costing. If the fixed overheadabsorption rate was $9 per unit, calculate the profit using marginalcosting. (b) When opening inventory was 8,500litres and closing inventory was 6,750 litres, a company had a profit of$62,100 using marginal costing. The fixed overhead absorption rate was$3 per litre. Calculate the profit using absorption costing. 4 The advantages and disadvantages of absorption and marginal costing Advantages and disadvantages of absorption and marginal costing
5 Chapter summary Test your understanding answers Test your understanding 1(a) Total variable costs = $(3 + 6 + 2 + 5) = $16 Contribution per unit (selling price less total variable costs) = $21 – $16 = $5 Total contribution earned = 3,000 x $5 = $15,000 (b) Total profit/(loss) = Total contribution – Fixed production overheads incurred = $(15,000 – 25,000) = $(10,000) Test your understanding 2(a) Working Test your understanding 3(a) Since inventory levels have fallen in the period, marginalcosting shows the higher profit figure, therefore marginal costingprofit will be $18,000 higher than the absorption costing profit, i.e.$110,000. (b) Inventory levels have fallen in the period and therefore marginalcosting profits will be higher than absorption costing profits.Absorption costing profit is therefore $5,250 less than the marginalcosting profit.
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