Activity-based costing (ABC) is a costing method that assigns overhead and indirect costs to products or services based on the activities that consume those resources. Instead of spreading all overheads evenly across output, ABC traces each cost to the activity that caused it, giving businesses a much more accurate picture of what each product or service actually costs to produce.
What is activity-based costing?
Activity-based costing (ABC) is a type of costing method that works by identifying the specific activities involved in producing a product or delivering a service, assigning costs to those activities and allocating them to products based on usage.
Traditional costing uses a single rate, often based on machine hours or direct labour, to allocate all overheads. This can distort costs when products consume resources very differently. ABC corrects this by using multiple cost drivers, making it more suitable for businesses with diverse product lines or complex operations.
For example, a manufacturer producing both a simple bolt and a custom-engineered component may spend far more time on quality checks and machine setup for the latter. Under traditional costing, both products absorb the same overhead rate. Under ABC, the custom component bears a higher share of inspection and setup costs, reflecting its actual resource consumption.
The table below sets out the core differences between traditional costing and activity-based costing:
|
Aspect |
Traditional costing |
Activity-based costing |
|
Overhead allocation |
Single plant-wide rate |
Multiple activity-based rates |
|
Basis |
One measure, usually machine hours or direct labour |
Cost drivers specific to each activity |
|
Accuracy with diverse products |
Low; distorts cost when products differ |
High; reflects actual resource use |
|
Cost to implement |
Low, simple to run |
Higher, needs setup and upkeep |
|
Best suited to |
Simple, homogeneous product lines |
High overhead, varied product mixes |
What are activity cost pools?
An activity cost pool groups indirect costs associated with a particular business activity.
Instead of combining all overhead into one general pool, ABC separates overhead according to the activities that create it. This gives the business a clearer basis for allocating each type of cost.
Examples include:
| Activity cost pool | Costs that may be included |
|---|---|
| Machine setup | Setup labour, equipment preparation and setup-related support costs |
| Quality inspection | Inspection staff, testing and quality-control costs |
| Purchasing | Purchase-order processing and procurement administration |
| Material handling | Movement, storage and handling of materials |
| Customer service | Support staff and service-related costs |
Each activity cost pool has a corresponding cost driver that the business uses to distribute the cost among products, services or other cost objects.
What are cost drivers in activity-based costing?
A cost driver is the factor that causes or closely relates to the cost of an activity.
ABC uses cost drivers to determine how much of an activity each product or service consumes. Choosing the right driver matters because it determines how the business allocates overhead.
Common examples include:
| Activity | Typical cost driver |
|---|---|
| Machine setup | Number of setups |
| Purchasing | Number of purchase orders |
| Quality inspection | Number or hours of inspections |
| Production | Machine hours |
| Order processing | Number of orders |
| Material handling | Number of material movements |
| Customer support |
Number of service requests |
For example, if setup costs increase mainly when employees perform more setups, the number of setups gives a stronger allocation basis than production volume.
OpenStax similarly identifies drivers such as orders, machine setups, purchase requisitions, labour hours and inspection hours when explaining ABC allocation.
What are the key steps in the activity-based costing process?
Implementing ABC requires a structured approach. These are the general steps involved:
- Identify activities: List every activity that consumes resources in the production or service delivery process. These could include machine setup, quality inspection, order processing or customer support.
- Assign costs to activity pools: Group costs into activity cost pools. Each pool collects all the costs associated with one specific activity. For instance, all costs related to running the quality inspection process go into a single pool.
- Determine cost drivers: A cost driver is the factor that causes a cost to be incurred. For machine setup, the cost driver might be the number of setups performed. For order processing, it could be the number of orders received.
- Calculate activity rates: Divide the total cost in each pool by the total units of the corresponding cost driver. This gives you the cost per unit of activity.
- Assign costs to products or services: Multiply the activity rate by the number of times each product uses that activity. Summing these across all activities gives the total overhead cost attributable to that product.
- Analyse and act: Use the results to review pricing, identify loss-making products and find activities where costs can be reduced.
How is activity-based costing calculated?
Activity-based costing calculates overhead in two stages.
Activity rate = Total cost in activity cost pool ÷ Total quantity of the cost driver
Then:
Overhead allocated to a product or service = Activity rate × Cost driver units consumed
For example, a business can calculate a setup rate by dividing total setup costs by the total number of setups. It then applies that rate based on how many setups each product requires.
The business repeats this process for each activity cost pool and adds the allocated amounts to determine the total overhead assigned to a product or service.
Activity-based costing example
Consider a manufacturer that produces two products: Product A and Product B.
The business has two overhead activity pools:
| Activity | Total cost | Cost driver | Total driver quantity | Activity rate |
|---|---|---|---|---|
| Machine setup | ₹3,00,000 | Number of setups | 60 | ₹5,000 per setup |
| Quality inspection | ₹1,80,000 | Inspection hours | 900 | ₹200 per hour |
Product A uses:
- 20 machine setups
- 300 inspection hours
Product B uses:
- 40 machine setups
- 600 inspection hours
The allocation becomes:
| Product | Setup cost | Inspection cost | Total allocated overhead |
|---|---|---|---|
| Product A | 20 × ₹5,000 = ₹1,00,000 | 300 × ₹200 = ₹60,000 | ₹1,60,000 |
| Product B | 40 × ₹5,000 = ₹2,00,000 | 600 × ₹200 = ₹1,20,000 | ₹3,20,000 |
Product B receives twice as much overhead because it consumes twice as much of both activities.
ABC exposes this difference directly. A single overhead rate could hide the higher resource consumption of Product B and distort its apparent profitability.
What are the advantages of activity-based costing?
ABC offers several practical advantages over conventional costing methods, particularly for businesses with varied product mixes or high indirect cost ratios.
- Accurate product costing: By tying overhead costs to actual resource consumption, ABC produces a more realistic cost per product. This prevents underpricing profitable items and overpricing others.
- Better pricing decisions: When you know the true cost of producing something, setting a price that covers costs and delivers a margin becomes far more straightforward.
- Identifying non-value-adding activities: ABC forces you to examine every activity in the business. Activities that consume cost without adding value to the customer become visible and can be reduced or eliminated.
- Improved profitability analysis: Management can assess profit margins at the product, customer or channel level rather than relying on blended averages.
- Support for strategic planning: With reliable cost data, businesses can make more confident decisions about product rationalisation, outsourcing and capacity allocation.
What are the disadvantages of activity-based costing?
ABC is not without drawbacks. Understanding these helps businesses decide whether it is the right approach for them.
- Time and cost of implementation: Identifying activities, setting up cost pools and selecting cost drivers requires significant effort. For smaller businesses, the setup cost may outweigh the benefit.
- Ongoing maintenance: Activity costs and drivers need regular review. If the business changes its processes, the cost model must be updated to remain accurate.
- Subjectivity in activity identification: Different analysts may identify different activities or choose different cost drivers for the same process, introducing inconsistency into results.
- Not suitable for every business: ABC is most beneficial when overhead costs are high and diverse. Businesses with simple, homogeneous product lines may find traditional costing adequate.
Activity-based costing vs traditional costing: what is the difference?
The main difference between activity-based costing and traditional costing is how each method allocates overhead. Traditional costing generally uses one or a small number of broad allocation bases. Activity-based costing separates overhead into activities and applies multiple cost drivers.
| Basis | Activity-based costing | Traditional costing |
|---|---|---|
| Overhead allocation | Uses multiple activity cost pools | Often uses a broad overhead pool |
| Cost drivers | Uses drivers specific to individual activities | Commonly uses volume-based drivers such as labour or machine hours |
| Accuracy | Better reflects different levels of resource consumption | Works well when products consume overhead in similar ways |
| Complexity | Requires more data and maintenance | Easier and less expensive to operate |
| Best suited for | Diverse products, complex operations and high overhead | Simpler operations and more homogeneous products |
| Management insight | Shows which activities create cost | Provides broader product-cost information |
Neither method is automatically better in every situation. The correct approach depends on the business's cost structure and the decisions management needs to make.
Activity-based costing vs absorption costing
Absorption costing assigns all manufacturing costs, including fixed manufacturing overhead, to products. Businesses use it to determine product cost for inventory valuation and external financial reporting under the applicable accounting framework. Activity-based costing focuses on identifying the activities that create overhead and assigning those costs according to activity consumption. Businesses mainly use ABC for internal costing, pricing and profitability analysis.
| Basis | Activity-based costing | Absorption costing |
|---|---|---|
| Main purpose | Detailed internal cost analysis and decision-making | Full manufacturing product costing |
| Overhead allocation | Uses activity pools and multiple cost drivers | Absorbs manufacturing overhead into products using selected allocation bases |
| Detail | More granular | Generally broader |
| Main use | Pricing, profitability, process and cost analysis | Product costing and inventory valuation |
| Complexity | Higher | Usually lower |
When should a business use activity-based costing?
A business should use activity-based costing when broad overhead allocation no longer shows how products, services or customers actually consume resources.
ABC works particularly well when:
- Overhead forms a significant portion of total cost
- The business sells several products or services
- Products require very different levels of support or processing
- Some products have high volumes while others have low volumes
- Setup, inspection, purchasing or support activities vary substantially
- Traditional costing produces margins or prices that management believes are distorted
- Management needs detailed product, customer or process profitability information
ABC provides less benefit when operations are simple, products are highly similar, and overhead is low.
How does activity-based costing help with pricing and profitability?
Activity-based costing helps businesses price more accurately by showing the overhead resources each product or service actually consumes.
Traditional averages can hide differences between simple and complex offerings. A high-volume standard product can require few setups and inspections, while a low-volume customised product can consume much more support activity.
ABC assigns those costs separately. This helps management identify:
- Products priced below their actual cost
- Products carrying too much overhead under the existing costing system
- Customers or channels that require unusually high support
- Activities that reduce margins
- Products or services that generate stronger margins than broad averages suggest
Management can then use this information to adjust prices, redesign processes, change the product mix or reduce unnecessary activity. Accurate product cost is also an important input when businesses set selling prices.
Can activity-based costing be used for service businesses?
Yes. Service businesses can use activity-based costing to assign indirect costs to services, customers, projects or other cost objects. The principle remains the same as in manufacturing: identify activities, group their costs and allocate those costs using relevant drivers.
For example:
- A hospital can allocate administrative or diagnostic-support costs using patient visits or procedures.
- A bank can allocate processing costs using numbers of transactions or customer requests.
- A logistics business can allocate support costs using deliveries, routes or orders.
- A consulting firm can allocate support costs using projects, client interactions or service hours.
- A hotel can allocate certain operating costs based on bookings, occupied rooms or guest services.
Service businesses often carry substantial indirect costs, which makes understanding the activities that create those costs particularly useful. Research and accounting literature also recognise ABC's application beyond manufacturing.
How can accounting software support activity-based costing?
Accounting software supports activity-based costing by helping businesses capture, organise and analyse the cost information required for activity-based costing.
Accounting software can help businesses:
- Record direct and indirect expenses
- Group costs by department, project, cost centre or activity
- Track the data used as cost drivers
- Compare costs across products or business units
- Maintain consistent cost records
- Generate reports for cost and profitability analysis
The accounting software does not automatically determine the correct activity pools or cost drivers. Management still needs to define the ABC model based on how the business actually consumes resources.
TallyPrime supports cost tracking through cost centres and related reports, helping businesses organise the underlying cost information used for management analysis.
Conclusion
ABC gives businesses a more honest view of costs than blanket overhead allocation can provide. When pricing decisions are based on what products actually consume, the risk of carrying undercosted lines or walking away from profitable ones is far lower. Maintaining accurate cost data is where the discipline tends to break down over time, particularly as product mixes and processes change.
TallyPrime supports businesses in tracking costs, managing accounts and generating the financial reports that activity-based costing analysis depends on, helping you move from raw data to reliable cost insight faster.
