Strategic Cost Management · Activity Based Cost Management

Introduction to Activity Based Costing (ABC)

Updated 11 October 2026 · Fact-checked

Activity Based Costing (ABC) assigns overheads to products in two stages. First, costs are collected in activity cost pools. Then each pool is charged to products using a cost driver, such as number of set-ups. It gives more accurate product costs than a single volume-based overhead rate.

Understand Introduction to Activity Based Costing (ABC)

Traditional absorption costing spreads overheads over products using one volume-based rate, such as direct labour hours or machine hours. This works when overheads really move with volume and products are similar. It fails when overheads are large and products differ in complexity.

ABC starts from a different idea: products consume activities, and activities consume resources. A product that needs many set-ups, inspections and orders uses more support activity than a simple, high-volume product, even if both use the same labour hours. ABC charges each product for the activities it actually uses.

Key terms:
- Activity: a task or work done in the organisation, such as machine set-up, material handling, quality inspection or order processing.
- Cost pool: a group of overhead costs related to one activity or a set of similar activities.
- Cost driver: the factor that causes the cost of an activity to change. It is the basis used to charge the pool to products, for example number of set-ups or number of inspections.

Traditional costing usually over-costs high-volume, simple products and under-costs low-volume, complex products. This is called product cost distortion. It can lead to wrong pricing, wrong product mix and wrong decisions to drop or push products.

Objectives of ABC: to find true product and customer cost, to trace overheads on cause-and-effect basis, to show which activities add no value, and to support pricing and cost control. ABC is most useful where overheads are high, product variety is wide and production is complex. It costs more to run, since you must identify activities and collect driver data.

Key rules to remember

Cost driver rate: Cost driver rate = Total cost of the activity pool ÷ Total volume of the cost driver; Use the expected or budgeted driver volume for the period, for all products together.
Overhead charged to a product: Overhead charged = Cost driver rate × Quantity of driver used by the product; Repeat for each pool and add the results.
Overhead per unit under ABC: Overhead per unit = Total overhead charged to the product ÷ Units produced; Add direct material and direct labour to get full unit cost.
Traditional overhead absorption rate: Rate = Total overheads ÷ Total base (labour hours or machine hours); Use this for comparison with ABC.

How to solve Introduction to Activity Based Costing (ABC) questions

Use this order for any introductory ABC question, whether it asks for theory or a small calculation.

1Read the question and note whether it asks for concept, comparison or a number.
2List the main activities and the overhead cost of each, which forms the cost pools.
3Choose the cost driver for each pool, based on what really causes the cost.
4Calculate the driver rate for each pool: pool cost ÷ total driver volume.
5Multiply each rate by the driver quantity used by each product and add across pools.
6Divide by units to get overhead per unit and add direct costs for total unit cost.
7If asked, compare with the traditional rate and state which products were over-costed or under-costed.
8Close with a one-line conclusion on pricing or decision impact.

Quickest way: Table-first ABC calculation

When to use it: Use for numerical parts with two or three activities and two or three products, where time is short.

Draw a small table: rows are activities, columns are pool cost, total driver volume and rate.
Fill the rate column first. Check that driver volumes of all products add up to the total.
Make a second table with products in columns and charge each activity row as rate × driver used.
Total each column and divide by units.
Do a quick check: the total overhead charged to all products must equal total overhead in the pools.

Common mistakes in Introduction to Activity Based Costing (ABC)

Choosing a volume-based driver such as labour hours for every activity.
Students carry over the traditional costing habit.
Fix: Ask what causes the activity cost. Set-up cost follows number of set-ups, not hours.
Confusing cost pool with cost driver.
Both terms appear together and look similar.
Fix: Pool is the amount of cost collected. Driver is the measure used to spread it. Write both in your table.
Dividing the pool cost by the driver volume of one product only.
Students rush and use the first product's figure.
Fix: Always use the total driver volume of all products for the rate.
Saying ABC always gives lower cost or higher profit.
Students think a better method must improve results.
Fix: ABC only changes how overhead is shared. Total cost stays the same. Some products cost more and some cost less.
Ignoring limits of ABC in theory answers.
Students only learn the advantages.
Fix: Add that ABC is costly to install, needs reliable driver data, and some costs still need arbitrary allocation.
Writing the traditional versus ABC difference as a list without a reason.
Students memorise points without logic.
Fix: For each point, link it to cause and effect: traditional uses volume, ABC uses activities.

Worked examples

Example 1

Explain the limitations of traditional absorption costing and how ABC addresses them. Then state what is meant by cost pool and cost driver.

Show the solution

Limitation 1: a single volume-based rate assumes overheads vary with volume. In modern firms, most overheads vary with complexity, orders and set-ups.
Limitation 2: simple, high-volume products absorb too much overhead and complex, low-volume products absorb too little. This is cost distortion.
Limitation 3: distorted costs mislead pricing, product mix and drop decisions.
ABC response: it groups overheads into activity pools and charges each by the driver that causes the cost, so products pay for the activities they use.
Cost pool: a group of overhead costs linked to an activity, such as all costs of material handling.
Cost driver: the factor that causes the pool's cost, such as number of material movements, used to charge the pool to products.

Answer: Traditional costing distorts product cost because it uses one volume base. ABC traces overheads through activities and cost drivers, giving more accurate costs. A cost pool is the cost collected for an activity; a cost driver is the measure used to spread that cost to products.

Example 2

A firm makes products X and Y. Overheads are set-up cost ₹1,20,000 and inspection cost ₹60,000. X: 1,000 units, 10 set-ups, 20 inspections. Y: 500 units, 30 set-ups, 40 inspections. Find the overhead per unit of each product under ABC. Compare with absorption on units produced.

Show the solution

Set-up driver total = 10 + 30 = 40 set-ups. Rate = ₹1,20,000 ÷ 40 = ₹3,000 per set-up.
Inspection driver total = 20 + 40 = 60 inspections. Rate = ₹60,000 ÷ 60 = ₹1,000 per inspection.
X: set-up = 10 × 3,000 = ₹30,000. Inspection = 20 × 1,000 = ₹20,000. Total = ₹50,000. Per unit = 50,000 ÷ 1,000 = ₹50.
Y: set-up = 30 × 3,000 = ₹90,000. Inspection = 40 × 1,000 = ₹40,000. Total = ₹1,30,000. Per unit = 1,30,000 ÷ 500 = ₹260.
Check: 50,000 + 1,30,000 = ₹1,80,000, equal to total overhead of 1,20,000 + 60,000.
Traditional on units: total units = 1,500. Rate = 1,80,000 ÷ 1,500 = ₹120 per unit for both products.

Answer: ABC overhead per unit: X ₹50 and Y ₹260. Traditional gives ₹120 for both. Traditional costing over-costs X and under-costs Y, because Y uses far more set-ups and inspections.

Exam tips

For theory questions, structure the answer as limitation, cause, effect on decisions, then how ABC fixes it.
Always define activity, cost pool and cost driver with one example each. Examiners look for these terms.
In numericals, show the rate for each pool separately and a final check that total overhead is fully charged.
When comparing methods, state clearly which product is over-costed or under-costed and what decision changes.
In case-scenario MCQs, identify the cost driver by asking what makes the cost rise, not what is easy to measure.

Practice questions from Activity Based Cost Management

Introduction to Activity Based Costing (ABC) in other exams

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

Introduction to Activity Based Costing (ABC): frequently asked questions

What is the difference between traditional costing and ABC?

Traditional costing absorbs overheads using one volume-based rate, such as labour hours. ABC first collects overheads by activity and then charges them using cost drivers. ABC links cost to the cause, so it is usually more accurate for diverse products.

What is a cost driver in ABC?

A cost driver is the factor that causes the cost of an activity to change. Examples are number of set-ups, purchase orders or inspections. It is used as the basis to charge the activity cost pool to products.

What is a cost pool?

A cost pool is a group of overhead costs related to one activity or similar activities. Each pool has its own cost driver. The pool cost divided by total driver volume gives the driver rate.

Does ABC change total cost?

No. ABC only changes how total overhead is shared among products. Total overhead charged under ABC equals total overhead under traditional costing. Individual product costs change.