What is activity-based costing? — Definition and distinction
Activity-based costing allocates overhead in indirect functions (procurement, logistics, order processing) along processes and their cost drivers. Methodologically, it is an extension of existing cost accounting rather than a new system — as Professor Weber argues in the canonical academic reference.
Activity-based costing is the cause-based allocation of overhead to processes rather than to cost centres. Where classical full-cost accounting pushes indirect cost onto direct cost through surcharge rates — typically as a percentage uplift on material or direct labour — activity-based costing breaks overhead blocks down into main processes, sub-processes, and cost drivers. This makes visible which activity causes which cost.
According to the Gabler Business Encyclopaedia, activity-based costing entry (Prof. Weber, WHU), activity-based costing "does not constitute a new cost accounting system" but a methodical improvement in how overhead is treated within full-cost, standard-cost, or contribution-margin accounting. It follows five steps: process analysis, allocation of cost to processes, definition of cost drivers, calculation of process costs, and process cost costing.
Three terms need to be separated to handle the method precisely: main processes and sub-processes (main processes group several sub-processes; for example, "Procurement" with sub-processes vendor onboarding, ordering, goods receipt); cost drivers (the quantity that triggers a process — number of purchase order lines or number of goods receipts); volume-induced (lmi) vs. volume-neutral (lmn) processes — lmi processes scale with the driver, lmn processes occur independently of volume (such as supplier master data maintenance).
The distinction from full-cost accounting is decisive in the Mittelstand. Companies that allocate overhead by surcharge rates treat small and large orders the same way — even though a fifty-euro order generates the same ordering and goods-receipt effort as a fifty-thousand-euro one. Activity-based costing exposes that distortion.
Why activity-based costing matters in the DACH Mittelstand in 2026
Rising overhead shares, variant proliferation, and outsourcing decisions sharpen the need for cause-based cost transparency. Classical surcharge calculation increasingly produces systematic misallocations in the Mittelstand — particularly in the small-order segment.
First, the overhead share is rising. Today, overhead in procurement, logistics, quality, IT, and order processing dominates — surcharge calculation distributes these blocks proportionally onto a shrinking direct-cost base, and the distortions skew operational decisions.
Second, variant variety is growing. Mass customisation and lot size one are reality in the Mittelstand. From our experience: rationalisation decisions made without an ABC foundation often cut precisely the variants that look loss-making on paper, while the actually profitable variants — once overhead is correctly allocated — are eliminated.
Third, make-or-buy logic is shifting. The true comparison cost includes supplier onboarding, ordering, goods receipt, quality checks, and complaint handling — all overhead blocks that disappear inside surcharge rates. Only an activity-based cost foundation makes the comparison defensible.
The methodological frame has been available for decades. Cooper and Kaplan published activity-based costing in the Harvard Business Review in 1988 as a response to the rising overhead share. The German adaptation as Prozesskostenrechnung is methodologically uncontested — what is contested is how deeply the Mittelstand really needs the concept.
Practice example: mid-sized manufacturer with logistics and procurement overhead
In a light-ABC project with a mid-sized manufacturer from southern Germany we showed what happens when three main processes — procurement, logistics, order processing — are calculated cleanly. The result: a clear shift in the internal view of the small-order business, without building a running ABC system.
A mid-sized manufacturer of technical components from southern Germany with around 180 employees called us in because the small-order business was contributing barely anything to coverage despite high utilisation. The existing full-cost calculation allocated overhead as a percentage uplift on direct labour. Management suspected structural misallocation but lacked a defensible data basis.
We set up a light activity-based cost model in four weeks. Three main processes, each with two to four sub-processes: procurement with supplier onboarding, ordering, goods receipt processing; logistics with put-away, picking, shipping preparation; order processing with quotation, order entry, invoicing. Per sub-process we agreed with the relevant process owner on a cost driver — number of purchase order lines, number of picking orders, number of order line items.
Data capture did not rely on lengthy time studies, but on estimation interviews with department leads and existing ERP data. We calculated a process cost rate for each sub-process: process cost divided by process volume per cost driver. Methodologically clean, pragmatic on data depth.
The result was expected in direction, surprising in sharpness. Small orders below 500 euro caused process costs in order processing and logistics that ran between 60 and 90 per cent of the order value. In the previous surcharge calculation, these costs had been buried as a percentage uplift on material — and were therefore invisible.
Management responded with a minimum-order-value rule and a bundling logic for small customers. The ABC model was not introduced as a running system, but repeated case by case — every two years, supplemented in case of business-model changes.
What ABC textbooks don't say
Three points rarely stated clearly in the textbook or consulting-deck literature, but decisive in the DACH Mittelstand. From more than 1,200 engagements we know the pattern.
1. Five reasons classical ABC fails in the Mittelstand
In our experience classical ABC fails in mid-sized companies for five recurring reasons. First, the data basis is missing: time recording in indirect functions is rarely complete. Second, there are no process owners: without clear accountability, cost drivers stay undefined. Third, there is no controlling staff for ongoing maintenance — ABC models age within months without upkeep. Fourth, projects fall in love with tools rather than method. Fifth, the process and cost-centre views blur, and methodical discipline is lost.
The International Association of Controllers (ICV) has documented this pattern in its activity-based cost management working groups for years and recommends case-by-case rather than continuous application in the Mittelstand.
2. The pragmatic light variant for two-hundred-person firms
For a Mittelstand company of 100 to 400 employees without a dedicated controlling staff, a reduced reading works far better than the full ABC method. From more than 1,200 engagements we distilled the following light variant: three to five main processes instead of forty — procurement, logistics, and order processing cover the relevant overhead block in most manufacturing Mittelstand companies. Annual rather than monthly run — ABC delivers steering impulses for strategic decisions, not day-to-day reporting. Spreadsheet instead of specialist tool — Excel or an equivalent carries a light ABC model. Focus on decision triggers — make-or-buy, variant calculation, price floor, outsourcing.
This reading aligns with the academic verdict. Weber notes in the Gabler entry that activity-based costing is "often too costly" and "usually run as a case-by-case calculation". We recommend this reading explicitly for the DACH Mittelstand.
3. ABC as process management strategy, not an accounting exercise
The central error in many ABC projects: they start in the controlling department without a process map for the company. Without a process owner the cost drivers remain unaccounted for; without a process map the structure of the main processes is missing. Activity-based costing is methodologically the bridge between process management and controlling — it only works if both disciplines are already in place. From 1,200+ engagements we know: companies that start with the calculation fail; companies that start with the process gain defensible steering information. The sequence — process map first, then process owners, then cost drivers, then rates — is not negotiable.
Our reading
Activity-based costing without a process map, without named process owners, and without a concrete decision context is an expensive arithmetic exercise. These three prerequisites belong before the method, not after it.
How we set up ABC in the Mittelstand (light variant, four phases)
We set up activity-based costing in the DACH Mittelstand in four phases — process map, driver and volume model, calculation run, decision workshop. Typical duration: four to six weeks. Effort: 20 to 40 person-days depending on complexity.
In vendor-neutral ERP and process consulting we view ABC not as an isolated controlling instrument but as part of the process architecture. Methodologically, the following four-step approach has proven itself with us:
Phase 1 — Process map and process-owner model. Identify three to five main processes, name one owner per main process, sketch the sub-processes. If no process map exists, build it here — otherwise ABC will not carry. We often pair this step with value stream mapping from the lean tradition.
Phase 2 — Cost driver and volume capture. Define a cost driver per sub-process — order lines, picking orders, order line items. Pull volume data from ERP, validate estimations with process owners. Process mining helps here when the ERP delivers clean transactional data.
Phase 3 — Calculation run and process cost rates. Determine process cost per main process, divide by process volume, derive process cost rates. Cleanly separate lmi and lmn shares. Spreadsheets are sufficient in the Mittelstand.
Phase 4 — Decision workshop with management. Results are not delivered as a report but discussed as a decision basis. Make-or-buy, minimum order values, variant rationalisation, price floor — the calculation is interpreted in the light of a concrete question. The difference from corporate-style consulting offers: we do not build a continuous ABC system requiring a controlling staff. We deliver defensible activity-based cost on a case-by-case basis for a concrete decision — pragmatic, not corporate overhead.
Common mistakes in activity-based costing
Four recurring failure patterns in mid-sized ABC projects. All of them are avoidable — if addressed before the method is chosen. Three are organisational, one is methodical.
Mistake 1 — Method before process map. The company starts ABC inside controlling without naming the main processes. Data capture turns into a debate over terminology. From Dreher practice: the leading cause in more than half of failed ABC projects.
Mistake 2 — Tendency to over-detail without economic justification. Instead of three main processes, forty sub-processes are modelled. Effort for data capture and maintenance explodes. Weber criticises this tendency in the Gabler entry explicitly. Remedy: maximum five main processes, maximum four sub-processes per main process.
Mistake 3 — Continuous operation instead of case-by-case calculation. The company tries to build monthly ABC without the controlling staff to maintain it. After three to six months, data maintenance and acceptance erode. We recommend annual runs and case-by-case updates.
Mistake 4 — No connection to decisions. The calculation is performed but no decision workshop scheduled. Results disappear into the controlling report. Without a concrete decision trigger, the leverage — and the perceived value — is missing.
Frequently asked questions
Classical full-cost accounting allocates overhead via surcharge rates onto direct cost — typically as a percentage uplift on material or direct labour. Activity-based costing breaks overhead into main processes, sub-processes, and cost drivers and allocates it on a cause basis. In practice that means: small orders carry their actual ordering and processing cost rather than passing it onto large orders via surcharge rates. The two systems can coexist — ABC extends full-cost accounting; it does not replace it.
From 1,200+ Dreher Consulting engagements we know: a light ABC model with three to five main processes is operational within four to six weeks, provided a process map exists. Without a process map, duration typically doubles, because main processes and process owners must be clarified first. We recommend four to six weeks for the light variant, then case-by-case repetitions every 18 to 24 months or with major business-model changes.
No. A light ABC model in the DACH Mittelstand runs on a spreadsheet. From our experience with mid-sized manufacturers, specialist software pays off only when a continuous run with monthly cycles is planned — which is rarely sensible in the Mittelstand. Case-by-case ABC works with Excel or an equivalent. Methodical discipline matters more than the tool: a clean process map, clear cost drivers, defensible volume data.
In most mid-sized companies, no. Prof. Weber notes in the Gabler Business Encyclopaedia that activity-based costing is "often too costly" and "usually run as a case-by-case calculation". This judgement matches our experience from 1,200+ engagements. A continuous ABC system pays off only when a dedicated controlling staff can carry the data maintenance and several strategic decisions arise per year. Otherwise we recommend the case-by-case light variant.
From 1,200+ engagements we know typical ranges: a light ABC model regularly uncovers cost structures that surcharge calculation makes invisible — particularly in order processing for small lot sizes and in procurement with many small suppliers. The concrete value emerges not from the model itself but from the decisions it supports — minimum-order-value rules, bundling logic, variant rationalisation, outsourcing. We recommend fixing the decision question before the project starts and sizing the effort accordingly.
Next steps
Before introducing activity-based costing, a short up-front clarification usually pays off: which decision should the calculation support, which main processes are in scope, who owns the process-owner role? Skipping that clarification produces a model nobody uses. More in our process management services and the ERP consulting practice. To complement the ABC discussion: order-to-cash, process owner, process mining, value stream mapping. Current practice notes in our Insights.
30 minutes with Matthias Müller
A structured assessment of your decision question — make-or-buy, variant rationalisation, or minimum order value. Pragmatic, methodical, from more than 1,200 Mittelstand engagements.
