What it means
Imagine a factory making a simple high-volume product and a complex low-volume one. Both use similar machine time, but the complex item needs many setups and inspections.
A single overhead rate based on machine hours hides that difference and makes the simple product subsidise the complex one. ABC fixes this by following the work.
List the main activities, such as purchasing, setup, inspection and order processing, and gather the costs of each into a cost pool. Then choose a cost driver (a measurable unit of activity, such as setups or inspection hours) that connects the pool to the products using it.
The rate for each pool is the pool cost divided by the total driver units. Each product is charged the rate multiplied by the units it consumed.
Direct materials and traceable labour are assigned directly, so ABC mainly improves the treatment of indirect cost. Good models are built around a decision, such as pricing, customer profitability or process improvement.
Too many pools make the model costly to maintain, and poor activity logs produce confident-looking but weak rates. Reconcile the total assigned cost back to the accounting records every period.
The main payoff is seeing cross-subsidies. Under a traditional single rate, a simple high-volume item is often overcharged while a complex custom item is undercharged.
ABC shows the true gap, which supports better pricing and minimum order sizes. ABC is a management tool, and its output is not the same as avoidable cost.
A product's fully allocated cost may exceed its price, yet stopping it may not save the shared setup team straight away. Use the results to ask questions about batch size, rework or order behaviour rather than as a verdict on a customer.
In practice
Real-world examples.
Example
A packaging manufacturer spreads $100,000 of setup overhead across 500 setups and charges $200 per setup. A short custom print run needing 10 setups absorbs $2,000, while a long standard run with one setup absorbs $200. The sales team uses the gap to set a minimum order size for custom work.
Example
A bank assigns back-office cost to customers by the number of manual transactions each one generates. Customers who rely on paper cheques turn out to cost far more to serve than those who bank online, which informs the fee schedule. The bank also uses the result to decide where to invest in self-service tools.
Example
A consulting firm assigns proposal-writing cost to client segments by hours of bid effort. It discovers that small, low-fee clients consume a disproportionate share of bid time and introduces a minimum engagement size. Partners then redirect that bid time towards larger, better-paying prospects.
Formula
Calculation
Activity rate = activity cost pool / total driver units. A setup pool of $100,000 and 500 setups in the period give $100,000 / 500 = $200 per setup. A custom product that needed 20 setups is assigned 20 x $200 = $4,000 of setup cost, while a standard product that needed 5 setups is assigned 5 x $200 = $1,000. Together the two products used 25 of the 500 setups, so 25 x $200 = $5,000 of the pool is accounted for.Case study
Seen in the real world.
Juniper Plastics is a fictional company created for this illustrative example. Its traditional machine-hour rate made its simple bulk product look expensive and a custom low-volume item look cheap.
Juniper then counted setups and inspections, built separate pools and found that the true cost pattern was reversed. Before changing any price it checked whether setup time could be reduced, and it did not assume the allocated overhead would vanish if the custom item were discontinued.
The finance team repeated the exercise a year later and updated the rates after a new quick-change tooling system cut setup time. The case shows ABC working as a living model that follows the business rather than a one-off study.
Watch out
Common mistakes.
- Choosing a driver because it is easy to count rather than because it reflects how the activity is actually used.
- Calling assigned shared overhead the fully avoidable cost of an individual order or customer.
- Leaving pool rates unchanged after a major process or capacity change.
Questions
People also ask.
Is ABC required for financial statements?
No. ABC is a management costing method used internally, while external reporting follows the applicable accounting standards, so the two sets of figures can differ.
What is a cost driver?
A measurable unit of activity used to assign a pool to products, such as setups, orders or inspection hours.
Does more detailed allocation guarantee better decisions?
No. Driver quality, the cost of maintaining the model and the decision actually being made all still matter.
From the founder's library
Take it further with the book.
Build your financial confidence beyond this definition. Shihan's full-length guide, Accounting Fundamentals, takes the same plain-English approach and turns it into a complete, practical playbook for non-finance managers, business owners and students - with chapter-end quiz answers and presentation slides included.
25% off with code MMHQ25, applied at checkout. Priced in USD - checkout may show the equivalent in your local currency.
View the book and save 25%Related