Activity based costing explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
If a factory spreads all its overhead on direct labour hours, a product that needs many set-ups, inspections and special orders looks cheaper than it is, and a plain, high-volume product looks dearer. Activity based costing traces overhead to the activities that cause it, and then to products by how much of each activity they use. It suits owners who suspect that their customised or low-volume work is not paying for itself.
Group overheads into cost pools by activity; choose for each pool a cost driver (the measure that makes the cost rise); compute cost per driver unit = pool cost ÷ total driver units; charge each product = driver units used × cost per driver unit. Use the result to reprice, redesign or drop products whose true cost the old method hid.
Not the same as ABC analysis of inventory
The "ABC analysis" used to grade stock by value is a different method; see ABC analysis of inventory. This article is about tracing overheads to products.
Why volume-based absorption distorts
A single rate such as ₹90 per direct labour hour assumes overhead rises in step with labour hours. But set-ups, inspections and order handling depend on the number of batches, inspections and orders, not on hours. Products made in small runs, or customised, use these activities heavily per unit; a labour-hour rate hides that. The machine hour rate fixes part of the problem, but still ignores activities that do not follow machine time. A costing and pricing analysis that uses activity pools is the way to see the difference on your own product lines.
The stages
- List the main activities and the overhead each consumes (from the primary distribution of overheads).
- Form cost pools: group activities that share a driver.
- Pick a cost driver for each pool: set-ups, inspections, machine hours, orders.
- Compute a cost per unit of driver.
- Assign each product's overhead = driver units × rate.
- Compare with the traditional result and decide.
Four levels help classify activities: unit-level (every unit, such as machine time), batch-level (set-ups, batch handling), product-sustaining (design, specification changes, testing) and facility-level (rent, general management, which have no sensible driver and are often left on a broad basis).
Worked example: a unit making a standard and a customised product
A factory makes a standard fitting (S) and a customised fitting (C). Figures are assumed for one year.
| Item | Standard | Customised |
|---|---|---|
| Units made | 3,000 | 500 |
| Direct material per unit (₹) | 200 | 300 |
| Direct labour per unit (₹) | 100 (1 hour) | 200 (2 hours) |
| Selling price per unit (₹) | 400 | 800 |
| Machine hours | 3,000 | 1,000 |
Overhead pool: ₹360,000. Labour hours: 3,000 + 1,000 = 4,000.
Traditional method. Rate = 360,000 ÷ 4,000 = ₹90 per labour hour. Standard carries 90 per unit; customised carries 2 × 90 = ₹180 per unit.
Activity based method. The ₹360,000 is split into four pools:
| Pool | Cost (₹) | Driver | Std units | Cust units | Total | Rate (₹) | To Standard (₹) | To Customised (₹) |
|---|---|---|---|---|---|---|---|---|
| Set-ups | 120,000 | Set-ups | 10 | 50 | 60 | 2,000 | 20,000 | 100,000 |
| Inspection | 90,000 | Inspections | 100 | 200 | 300 | 300 | 30,000 | 60,000 |
| Machine running | 100,000 | Machine hours | 3,000 | 1,000 | 4,000 | 25 | 75,000 | 25,000 |
| Orders and design | 50,000 | Orders | 20 | 80 | 100 | 500 | 10,000 | 40,000 |
| Total | 360,000 | 135,000 | 225,000 |
Check: pools 120,000 + 90,000 + 100,000 + 50,000 = 360,000; assigned 135,000 + 225,000 = 360,000.
Per unit: Standard = 135,000 ÷ 3,000 = ₹45; Customised = 225,000 ÷ 500 = ₹450.
Unit cost and profit compared
| Standard: traditional | Standard: ABC | Customised: traditional | Customised: ABC | |
|---|---|---|---|---|
| Direct material | 200 | 200 | 300 | 300 |
| Direct labour | 100 | 100 | 200 | 200 |
| Overhead | 90 | 45 | 180 | 450 |
| Total cost | 390 | 345 | 680 | 950 |
| Selling price | 400 | 400 | 800 | 800 |
| Profit per unit | 10 | 55 | 120 | −150 |
Total profit is the same under both methods: traditional = 3,000 × 10 + 500 × 120 = 30,000 + 60,000 = 90,000; activity based = 3,000 × 55 + 500 × (−150) = 165,000 − 75,000 = 90,000. Only the picture changes.
What the owner decides. The customised product looked like the star at ₹120 profit per unit and is in fact losing ₹150 on every unit; its price would need to rise to about ₹950 just to break even on full cost. Options: raise the price for custom work, charge a separate set-up fee, restrict minimum order sizes, or simplify the design. Meanwhile the standard line is more profitable than thought, which supports pricing it keenly.
Reading the result with care
ABC changes who carries the shared costs; it does not create or remove cost. In a short-term decision, only the costs that actually vanish if the product is dropped matter; many set-up and inspection costs fall only if staffing changes. See the break-even and relevant-cost guides for that test. Rates in a pool are valid only if the cost does move with the chosen driver.
Limits and when it is worth the effort
Activity based costing needs data (counts of set-ups, inspections, orders), management time and review of drivers. It repays the effort when overheads are large against direct costs, the product range is varied, and volumes differ widely. For a single-product firm it adds nothing. Facility-level costs still need an arbitrary basis.
Common mistakes
- Choosing too many pools, so the data cost exceeds the insight.
- Picking a driver because it is easy to count, not because cost follows it.
- Treating the ABC unit cost as the minimum price for every order.
- Forgetting to refresh drivers after layout or process changes.
Need help with product profitability?
A good first step is a one-year view of overhead by activity and of the products that draw on each. We can help build that through a costing and pricing analysis and carry the result into prices.
Key takeaways
- Group overheads into activity pools and trace them by cost drivers.
- Cost per driver unit = pool cost ÷ total driver units; product charge = driver units × rate.
- Volume-based absorption overcosts high-volume plain products and undercosts low-volume or complex ones.
- Total profit does not change; the split between products does.
- Use ABC where overhead is large and the range is varied; keep the pools few.
Read next
- Overhead absorption rates and the machine hour rate
- ABC analysis of inventory, FSN and VED
- Break-even point, contribution and margin of safety
Disclaimer: The methods described are standard cost accounting and financial management techniques. The worked example uses an invented business and invented figures, including any tax, interest or exchange rate, which are assumptions for illustration and not current rates. Where the article refers to a legal requirement, the linked guide and the official text should be checked. This article is general information, not legal advice; check the official text before acting.