Cost Accounting · Overheads

Treatment of Special Overheads in Cost Accounting

Updated 10 October 2026 · Fact-checked

Special overheads are items that do not fit the normal factory, office or selling split. Each has a set treatment: include it in product cost, charge it to the costing profit and loss account, or exclude it. Decide by asking whether the cost is incurred to make and sell the product, or is a financial or abnormal item.

Understand Treatment of Special Overheads

Most overheads are easy to place. Rent goes to the factory or office, and advertising goes to selling. A few items cause doubt. These are research and development, packing, royalty, interest on capital, and idle capacity. Examiners test them because the right treatment is a matter of principle.

The guiding idea is simple. Cost accounting records the cost of producing and selling the product in normal conditions. A cost that is normal and linked to the product goes into product cost. A cost that is abnormal, or is a return to capital providers rather than a cost of operation, is kept out of product cost.

Research and development (R&D). Research that improves a current process or product is a production overhead. Spread it over the units produced. R&D done for one specific customer or job is charged directly to that job. Large R&D that gives a benefit in future periods is deferred and amortised (written off) over the periods that benefit. Follow the instruction in the question on the benefit period.

Packing. There are two kinds. Primary packing is needed to hold the product, such as a tube for toothpaste. It is a direct cost of the product. Secondary packing is for handling and transport, such as outer cartons. It is a selling and distribution overhead. Special packing for one job is charged directly to that job. Returnable packing is not a cost. Only its loss or depreciation is charged.

Royalty. Royalty on production, paid per unit made, is a direct expense of the product. Royalty on sales, paid per unit sold, is a selling and distribution overhead. Minimum rent or royalty paid for a mine or licence is a fixed charge. If the minimum is not recovered by actual output, the shortfall is often recoverable in later years, so it is carried forward.

Interest on capital. Interest on own capital is a notional cost of using funds. In financial accounts it is not an expense. Under CAS 17 (Interest and Financing Charges), interest and financing charges are not part of cost, and notional interest on own funds is not included in cost of products. They are shown in the costing profit and loss account. In exam questions, read the instruction. If it says to include interest on capital, include it as a notional cost. Then reverse it in the reconciliation with the financial accounts.

Idle capacity. Normal idle capacity is unavoidable, for example from holidays, maintenance and setting up. Its cost is absorbed in the cost of production. Abnormal idle capacity comes from avoidable causes such as a strike, power failure or lack of orders. Its cost is not charged to products. It is written off to the costing profit and loss account. The same split applies to idle time of labour.

Key rules to remember

Idle capacity cost: Idle capacity cost = Fixed overhead ÷ Budgeted (or normal) capacity × Idle capacity units; Use the rate based on normal or budgeted capacity. Split the result into normal and abnormal parts.
Overhead rate on normal capacity: Rate = Total fixed overhead ÷ Normal capacity (units or hours); Normal idle capacity is already inside this rate, so it is absorbed into product cost.
Abnormal idle capacity: Abnormal idle capacity cost = Idle units due to abnormal causes × Fixed overhead rate; Charge to the costing profit and loss account. Do not include in product cost.
Royalty treatment rule: Royalty on production = direct expense; Royalty on sales = selling overhead; The basis of payment decides the treatment.
Packing treatment rule: Primary packing = direct cost; Secondary packing = selling and distribution overhead; Special packing for a job is charged directly to that job.
R&D treatment rule: Process or product improvement R&D = production overhead; Specific-job R&D = direct cost of the job; Large R&D with future benefit = amortised over the benefit period; Spread production overhead R&D over output of the period.
Interest on capital rule: Financial interest = excluded from cost; Notional interest = included only if instructed; If included in cost, reverse it in the reconciliation with financial accounts.

How to solve Treatment of Special Overheads questions

Use this method for any question on special overhead items. It works whether the question asks for a treatment note or a cost sheet figure.

1List every special item in the question: R&D, packing, royalty, interest, idle capacity, and any others.
2For each item, find its nature. Check whether it is direct or indirect, normal or abnormal, and whether it is production-related or sales-related.
3Check the instructions. Notional interest, for example, is included or excluded only as the question directs.
4Place each item: product cost (direct or factory overhead), selling and distribution overhead, deferred cost, or costing profit and loss account.
5Compute any amounts. For idle capacity, find the rate on normal or budgeted capacity and multiply by idle units. Split normal and abnormal.
6Absorb normal items in product cost. Write off abnormal items separately. Do not mix them into the cost per unit.
7Prepare the cost statement or note, showing each item on a separate line with a one-line reason for the treatment.
8Match the quantity base to the item. Production-based items use units produced. Sales-based items use units sold.

Quickest way: Three-bucket sorting

When to use it: Use when you have little time and the question lists several items to classify or place in a cost sheet.

Write three columns: Product cost, Selling and distribution, Not in cost (costing P&L).
Put normal production items in the first column. Examples are production royalty, primary packing, normal idle capacity and current R&D.
Put sales-linked items in the second column. Examples are sales royalty and secondary packing.
Put abnormal idle capacity, financial interest and similar items in the third column.
Total each column and then complete the cost sheet.

Common mistakes in Treatment of Special Overheads

Loading abnormal idle capacity cost into product cost.
Students treat all idle cost as a fixed overhead to be absorbed.
Fix: Split idle cost into normal and abnormal. Only the normal part is absorbed. Write off the abnormal part to the costing profit and loss account.
Treating all packing as a selling overhead.
Packing sounds like part of dispatch.
Fix: Primary packing needed to hold the product is direct cost. Only secondary packing for transport is selling and distribution overhead.
Treating royalty the same way in every case.
Students remember royalty as a direct expense and stop there.
Fix: Check the basis. Royalty per unit produced is direct. Royalty per unit sold is a selling overhead.
Including interest on capital in the cost sheet without instruction.
Students see it as a cost of funds and assume it belongs in cost.
Fix: Exclude financing charges by default. Include notional interest only when the question asks for it, and then reverse it in the reconciliation.
Calculating the idle capacity rate on actual capacity instead of normal or budgeted capacity.
Students divide fixed overhead by actual output because it is the easiest figure.
Fix: Use normal or budgeted capacity as the base. The rate must not change because of idle time.
Charging large one-off R&D entirely to one period's cost.
Students treat every R&D cost as a current expense.
Fix: If the benefit extends over future periods, defer the cost and amortise it over the benefit period, as the question directs.

Worked examples

Example 1

A factory has a normal capacity of 10,000 machine hours per month. Fixed overhead is ₹5,00,000 per month. In one month, the machine ran for 8,000 hours. Of the 2,000 idle hours, 500 were due to routine maintenance and setting up, and 1,500 were due to a power failure. Compute the idle capacity cost and state its treatment.

Show the solution

Fixed overhead rate = ₹5,00,000 ÷ 10,000 hours = ₹50 per hour.
Total idle capacity cost = 2,000 hours × ₹50 = ₹1,00,000.
Normal idle capacity = 500 hours × ₹50 = ₹25,000. This is unavoidable, so it is absorbed in the cost of production.
Abnormal idle capacity = 1,500 hours × ₹50 = ₹75,000. The power failure is an avoidable cause.
Check: ₹25,000 + ₹75,000 = ₹1,00,000.

Answer: Idle capacity cost is ₹1,00,000. ₹25,000 (normal) is absorbed in product cost. ₹75,000 (abnormal) is written off to the costing profit and loss account.

Example 2

Sharma Textiles produced 4,000 units and sold 3,500 units, so 500 units remain in closing stock. Direct material was ₹2,40,000 and direct wages ₹1,60,000 for the 4,000 units produced. Royalty is ₹5 per unit produced and ₹3 per unit sold. Primary packing costs ₹2 per unit produced. Secondary packing costs ₹1 per unit sold. Interest on a bank loan was ₹20,000. Compute the prime cost and the selling and distribution items, and state the treatment of the interest.

Show the solution

Production-based items use the 4,000 units produced. Selling items use the 3,500 units sold.
Production royalty = 4,000 × ₹5 = ₹20,000. This is a direct expense.
Primary packing = 4,000 × ₹2 = ₹8,000. This is a direct cost.
Prime cost (for 4,000 units) = ₹2,40,000 + ₹1,60,000 + ₹20,000 + ₹8,000 = ₹4,28,000.
Sales royalty = 3,500 × ₹3 = ₹10,500. This is a selling overhead.
Secondary packing = 3,500 × ₹1 = ₹3,500. This is a selling and distribution overhead.
Total selling and distribution items (for 3,500 units sold) = ₹10,500 + ₹3,500 = ₹14,000.
Interest on the loan of ₹20,000 is a financing charge. It is excluded from the cost sheet and shown in the costing profit and loss account.

Answer: Prime cost for 4,000 units is ₹4,28,000. Selling and distribution items for 3,500 units sold total ₹14,000. Interest of ₹20,000 is excluded from the cost sheet.

Exam tips

Always state the treatment in words as well as figures. Many questions give marks for the reason.
Read the basis of payment for royalty and the purpose of packing before you place the item.
For idle capacity, show the rate, the normal and abnormal split and the final treatment on separate lines.
If the question gives notional interest, check whether the instruction is to include or exclude it. Say so in your answer.
In MCQs, look for the one word that decides the case: abnormal, primary, production basis or notional.

Practice questions from Overheads

Treatment of Special Overheads in other exams

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

CA IntermediateTreatment of Special Items in Cost Sheet

Treatment of Special Overheads: frequently asked questions

How is abnormal idle capacity treated in cost accounting?

It is not charged to the product. It is written off to the costing profit and loss account. This keeps product cost free of avoidable waste.

Is royalty a direct or indirect cost?

It depends on the basis. Royalty on units produced is a direct expense. Royalty on units sold is a selling and distribution overhead.

Is interest on capital included in cost?

Not in a normal cost sheet. Interest and financing charges are excluded, as CAS 17 provides. Notional interest on own capital is included only when the question specifically asks for it, and it is then reversed in the reconciliation.

How is research and development cost treated?

R&D for improving current processes or products is a production overhead spread over output. R&D for a specific job is charged directly to that job. Large R&D with future benefit is amortised over the periods that benefit.