Costing and Taxation · Ch 5 — Basic Concept of Overhead
Overhead: Meaning, Importance, Classification and Distinction from Prime Cost
Overhead: Meaning, Importance, Classification and Distinction from Prime Cost
Classification of Cost (Cost Sheet) already introduced Overhead briefly, as the sum of every Indirect cost — Indirect Material, Indirect Labour, and Indirect Expenses — that cannot be conveniently and specifically traced to one particular unit of output. This chapter goes further: why Overhead needs a whole procedure of its own to be charged fairly across products and departments, how it is classified, and how it is formally distinguished from Prime Cost.
Meaning of Overhead
Overhead is the aggregate of indirect costs incurred for the business as a whole, or for a department, which cannot be identified with, and directly charged to, any one specific cost unit, job, or product. Because it cannot be traced directly, Overhead must instead be spread — using some reasonable, defensible basis — over the various units, jobs, or departments that share it.
Importance of Overhead
Getting Overhead right matters for several reasons:
- Accurate product costing — if Overhead is wrongly charged to a product (too much or too little), the reported cost of that product is wrong, and every decision built on that cost (pricing, profitability comparison between products) is distorted.
- Price fixation — a selling price built on an understated Overhead charge risks selling below true cost without the business realising it.
- Cost control — comparing actual Overhead incurred, department by department, against a budgeted or standard figure is one of the main tools of cost control; this comparison is only meaningful if Overhead has first been correctly distributed to the right department.
- Growing share of total cost — in most modern manufacturing and service businesses, Overhead (factory automation, administration, marketing, technology) often forms a much larger share of total cost than it did when cost accounting was first developed around direct material and direct labour — making a rigorous, well-understood Overhead procedure more important, not less, as time goes on.
Classification of Overhead
WBCHSE's Costing and Taxation syllabus classifies Overhead along the SAME three lenses already used for cost generally (Classification of Cost, Section 2), applied now specifically to the indirect portion of cost:
(i) Element-based classification
- Indirect Material — material consumed in production that either does not become part of the finished product, or is used in such small quantities per unit that tracing it is impractical (e.g., lubricating oil, cleaning materials, consumable stores).
- Indirect Labour — wages/salaries of employees who support production in general but cannot be traced to one unit (e.g., factory supervisor's salary, store-keeper's wages).
- Indirect Expenses — all other expenses that cannot be traced to a single unit (e.g., factory rent, insurance, general lighting).
(ii) Function-based classification
- Factory (Works) Overhead — indirect costs of running the production department (factory rent, machine depreciation, factory supervision, power).
- Office & Administration Overhead — indirect costs of general management and administration (office rent, administrative salaries, audit fees).
- Selling Overhead — indirect costs of creating demand and winning orders (advertisement, sales commission).
- Distribution Overhead — indirect costs of delivering already-produced/sold goods to the customer (warehousing of finished goods, carriage outward).
- Research & Development Overhead — indirect costs of developing or improving a product before it is finally offered for sale.
(iii) Behaviour-based classification
- Fixed Overhead — remains constant in total for a period regardless of output level (e.g., factory rent, insurance).
- Variable Overhead — changes in total broadly in proportion to output (e.g., power consumed per machine-hour run).
- Semi-Variable Overhead — contains both a fixed and a variable element within the same head (e.g., a telephone or electricity bill).
(This syllabus scopes Overhead classification to exactly these three bases — element, function, and behaviour — and does not extend to a further normal-versus-abnormal or controllable-versus-uncontrollable split at this level.)
Overhead vs Prime Cost
| Basis of distinction | Prime Cost | Overhead |
|---|---|---|
| Traceability | Directly traceable to a specific unit, job, or product | Cannot be traced to one specific unit; incurred for the business/department as a whole |
| Components | Direct Material + Direct Wages + Direct Expenses only | Indirect Material + Indirect Labour + Indirect Expenses, taken together |
| How it is charged to a unit | Charged directly, in the actual amount incurred for that unit | Charged only through a distribution/apportionment procedure, on some reasonable basis, since no direct link exists |
| Position in the Cost Sheet | The very first cost total built up | Added stage by stage AFTER Prime Cost — as Factory Overhead, then Office & Administration Overhead, then Selling & Distribution Overhead |
Overhead
The aggregate of Indirect Material, Indirect Labour, and Indirect Expenses — cost that cannot be traced to one specific unit and must instead be distributed across all units/departments sharing it, on some reasonable basis.
Why Overhead needs its own procedure
A Direct cost is charged to a unit in the ACTUAL amount incurred for that unit — no estimation is needed. An Overhead item, by definition, cannot be traced this way, so cost accounting must instead choose a fair BASIS (floor area, number of employees, machine hours, and so on) to divide it among the units or departments that share it — this is exactly the distribution procedure covered in Section 5.B.
WBCHSE's Costing and Taxation syllabus tests Overhead classification and distribution on the same cost-accounting foundations that CBSE/NCERT Accountancy students studying manufacturing costs also learn — the vocabulary (Factory Overhead, Allocation, Apportionment) is the shared language of cost accounting used across every Indian commerce-stream board.
The aggregate of Indirect Material, Indirect Labour and Indirect Expenses — cost that cannot be traced to one specific unit and must instead be distributed across the units/departments that share it, on a reasonable basis.
Indirect costs of running the production department — factory rent, machine depreciation, factory supervision, power — the function-based Overhead head that, added to Prime Cost, gives Factory Cost.