Management Accounting · Alternative cost accounting principles

How to Reconcile Marginal and Absorption Costing Profits

Updated 11 October 2026 · Fact-checked

Reconciling the two profits means explaining the difference using inventory movement. Difference = change in inventory units × fixed overhead absorbed per unit. If inventory rises, absorption costing profit is higher. If inventory falls, marginal costing profit is higher. If inventory is unchanged, the profits are equal.

Understand Reconciling Marginal and Absorption Costing Profits

Marginal costing and absorption costing treat fixed production overheads differently. Marginal costing charges the whole fixed overhead for the period as an expense. Inventory is valued at variable cost only.

Absorption costing adds a share of fixed production overhead to each unit made. That share sits in the inventory value. It only becomes an expense when the unit is sold.

So the two methods differ only when units made and units sold differ. If you make more than you sell, some fixed overhead is carried forward in closing inventory under absorption costing. Less expense is charged this period, so profit is higher.

If you sell more than you make, inventory falls. Fixed overhead held in opening inventory is released into this period's cost of sales. Absorption costing charges more expense, so its profit is lower than marginal costing profit.

The reconciliation simply measures the fixed overhead moved into or out of inventory. It does not matter which method you started with. The change in inventory tells you the direction, and the absorption rate tells you the size.

Key formulas to remember

Profit difference: Difference = (Closing inventory units − Opening inventory units) × fixed overhead absorbed per unit; Use units, not money values. The rate is the fixed production overhead absorption rate per unit.
Inventory increases: Absorption profit = Marginal profit + (inventory increase in units × fixed overhead per unit); Production is greater than sales.
Inventory decreases: Absorption profit = Marginal profit − (inventory decrease in units × fixed overhead per unit); Sales are greater than production.
Fixed overhead absorption rate: Rate per unit = Budgeted fixed production overhead ÷ Budgeted activity (units); Only fixed production overhead counts. Selling and administration costs are period costs in both methods.
Inventory unchanged: Marginal profit = Absorption profit; Production equals sales, so no fixed overhead moves in or out of inventory.

How to solve Reconciling Marginal and Absorption Costing Profits questions

Use this method for any question asking you to reconcile or explain the profit difference.

1Find the opening and closing inventory in units. If you are given production and sales, inventory change = production − sales.
2Decide the direction. Inventory up means absorption profit is higher. Inventory down means marginal profit is higher.
3Find the fixed production overhead absorbed per unit. Divide budgeted fixed production overhead by budgeted activity, unless the rate is given.
4Multiply the change in inventory units by the rate. This is the profit difference.
5Apply it to the profit you know. Add or subtract according to the direction in step 2.
6Check the answer. The absorption profit must be higher when inventory rises and lower when inventory falls.
7If the question has opening and closing inventory values under both methods, check that the difference in values equals the profit difference.

Quickest way: Three-line reconciliation

When to use it: Use this for multiple choice and number entry questions where you only need the size or the direction of the difference.

Write: production − sales = inventory change in units.
Multiply by the fixed overhead per unit.
Positive change: absorption profit is higher by that amount. Negative change: marginal profit is higher by the amount.

Common mistakes in Reconciling Marginal and Absorption Costing Profits

Using total inventory units instead of the change in inventory.
Students see the closing inventory figure and multiply it directly.
Fix: Always take closing minus opening units. Only the movement affects the profit difference.
Adding the difference when inventory falls.
Students memorise that absorption profit is higher and forget this only applies when inventory rises.
Fix: Ask the question: is inventory up or down? Up means absorption is higher. Down means absorption is lower.
Using the total unit cost, or the variable cost, instead of the fixed overhead rate.
The question gives several cost per unit figures and the wrong one gets picked.
Fix: Only the fixed production overhead per unit explains the difference. Ignore variable cost per unit.
Including selling or administration overheads in the absorption rate.
Students treat all fixed overheads alike.
Fix: Absorption costing under IFRS inventory valuation includes only production overheads. Non-production costs are expensed in the period under both methods.
Using the budgeted rate on units when the question gives actual production figures but the rate is based on a different activity level.
Students calculate the rate from actual output rather than from the budget.
Fix: Use the rate stated, or budgeted overhead ÷ budgeted activity. Do not recalculate from actual output.

Worked examples

Example 1

A company makes one product. Budgeted fixed production overhead is $60,000 for budgeted output of 20,000 units. In April it produced 5,000 units and sold 4,200 units. Marginal costing profit was $18,000. Opening inventory was nil. Calculate the absorption costing profit.

Show the solution

Fixed overhead absorption rate = $60,000 ÷ 20,000 = $3 per unit.
Inventory change = 5,000 − 4,200 = 800 units increase.
Profit difference = 800 × $3 = $2,400.
Inventory rose, so absorption profit is higher: $18,000 + $2,400 = $20,400.

Answer: Absorption costing profit is $20,400.

Example 2

A company absorbs fixed production overhead at $8 per unit. Opening inventory was 1,500 units and closing inventory was 900 units. Absorption costing profit for the year was $75,000. What was the marginal costing profit?

Show the solution

Inventory change = 900 − 1,500 = 600 units decrease.
Profit difference = 600 × $8 = $4,800.
Inventory fell, so absorption profit is lower than marginal profit by $4,800.
Marginal profit = $75,000 + $4,800 = $79,800.

Answer: Marginal costing profit is $79,800.

Exam tips

Read what profit you are given. Many questions give the marginal profit and ask for absorption profit, or the reverse. Adding when you should subtract is the commonest slip.
Write the direction before you calculate: inventory up or down. It takes five seconds and prevents sign errors.
In multiple response questions, check which statements are true for each inventory movement. Statements about equal profits are only true when inventory is unchanged.
In Section B, show the inventory units, rate and difference as separate lines. This helps you gain method marks even if a later figure is wrong.

Practice questions from Alternative cost accounting principles

Reconciling Marginal and Absorption Costing Profits in other exams

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

Reconciling Marginal and Absorption Costing Profits: frequently asked questions

Why is absorption costing profit higher when inventory increases?

Some of the period's fixed production overhead is included in the value of closing inventory and carried forward. Less fixed overhead is charged as an expense this period. Marginal costing charges all of it now, so its profit is lower.

Do the two methods ever give the same profit?

Yes, when opening and closing inventory units are equal. No fixed overhead moves into or out of inventory, so both methods charge the same fixed cost for the period.

Which fixed overhead rate do I use in the reconciliation?

Use the fixed production overhead absorbed per unit, normally budgeted fixed production overhead divided by budgeted activity. Do not use selling or administration overheads or the variable cost per unit.

Is the total profit over the life of the product different between methods?

No. Over the whole life of a product, when all units made have been sold, total profit is the same under both methods. The difference is only in timing between periods.