Preparing Overheads Distribution Summary: A Step-by-Step Guide

Every rupee spent on rent, electricity, or the works manager’s salary has to land somewhere before it becomes part of a product’s cost. That “somewhere” is decided through the overheads distribution summary, a working document that cost accountants prepare to trace indirect expenses to the departments that actually use them. It sounds like a paperwork exercise, but it is really the backbone of accurate product costing. Get it wrong, and every price you set afterward is built on a shaky number.

What the distribution summary actually does 🔗

Once overheads are collected and classified by nature, the next job is to figure out which department should bear which cost. This is called departmentalisation of overheads, and the overheads distribution summary is simply the spreadsheet-style record where that process is documented. Each row lists an overhead item, and each column represents a department, so a completed summary shows exactly how much of the factory’s total indirect cost sits with each production and service department.

This matters because a factory rarely has just one department. A typical manufacturing unit might have three production departments and a couple of service departments such as maintenance or stores. Dividing a factory into departments makes it possible to run operations efficiently and, just as importantly, to track cost responsibility department by department rather than treating the whole factory as one cost blob.

Primary distribution: the first pass 🔗

Primary distribution is the stage where every overhead item, without exception, is assigned to every department, production or service, on some rational basis. At this point, the accountant does not worry about whether a department actually makes the product or merely supports the ones that do. That distinction is dealt with later. The goal here is simply to make sure no overhead cost is left unassigned.

Allocation versus apportionment 🔗

Two techniques operate within primary distribution, and students often blur the line between them.

• Allocation applies when an overhead can be traced entirely to one department. Depreciation on a machine that belongs only to the packaging department, for instance, is allocated wholly to packaging because no other department uses that asset.
• Apportionment applies when an expense is shared. Factory rent, insurance on the building, or the salary of a works manager who oversees the whole plant cannot be pinned to a single department, so these costs are apportioned, or split, using a basis that reflects how much benefit each department actually receives.

The common basis of allocation includes direct labour hours, machine hours, or material cost, while apportionment leans on measures like floor area, number of employees, or asset value, depending on which measure best represents the underlying cause of the cost.

Choosing a fair basis 🔗

The basis chosen for apportionment is not arbitrary. It has to have a logical, measurable relationship with the expense being shared. A poorly chosen basis distorts departmental costs and, eventually, product prices. Some frequently used bases are:

Notice how the basis always mirrors the real driver of the cost. Floor area works for rent because a department occupying more space genuinely consumes more of that rent. This same logic is what makes choosing an appropriate apportionment basis a matter of professional judgment, not a mechanical formula.

At the end of primary distribution, every department, whether it makes products or merely supports the ones that do, has an overhead figure attached to it. This output is often called the primary distribution summary.

Secondary distribution: passing the baton 🔗

Here is the problem primary distribution leaves behind: service departments such as maintenance, stores, or the power house do not sell anything to customers. Their entire cost still needs to reach a product eventually, because customers are ultimately paying for maintenance and power just as much as for raw material. Secondary distribution solves this by reallocating service department overheads to the production departments that actually benefit from those services.

Three broad approaches are used, depending on how the service departments interact with each other.

Apportionment to production departments only 🔗

This is the simplest method. It assumes service departments serve only production departments and ignores any service that one service department renders to another. It is quick to apply but can understate the true cost of departments that lean heavily on internal support services.

Repeated distribution method 🔗

When service departments do serve each other, but you want to avoid heavy algebra, the repeated distribution method apportions each service department’s cost, round after round, until the remaining balances in service departments become negligible and can be closed off to production departments.

Simultaneous equation method 🔗

This is the mathematically precise version. It sets up equations representing the mutual exchange of services between departments and solves them together. It correctly captures reciprocal servicing, where, say, maintenance services the power house and the power house also supplies power back to maintenance. A worked example of allocating IT support and facility management costs to production departments based on usage illustrates how this reciprocal logic plays out in practice.

Putting the summary together: a worked illustration 🔗

Assume a factory has two production departments, A and B, and one service department, Maintenance. After primary distribution, the overheads stand as follows.

Once Maintenance’s cost is fully absorbed into A and B, the summary is complete. Departments A and B now carry the full overhead burden of the factory, and this final figure becomes the basis for calculating the overhead absorption rate that gets charged to individual products or jobs.

Why this summary earns its place in cost control 🔗

An overheads distribution summary is not prepared just to satisfy an accounting formality. It gives management a department-wise breakdown of indirect costs, which makes it possible to spot which departments are becoming disproportionately expensive to run. A production department whose share of overheads keeps climbing year after year, even after adjusting for output, is a signal worth investigating.

It also feeds directly into pricing and profitability analysis. If overheads are apportioned on an outdated or unrealistic basis, such as using floor area from three years ago when a department has since expanded, the resulting product costs will be misleading. Since apportionment is based on the benefit each department is estimated to receive, keeping the basis current is part of maintaining the summary’s usefulness. This is why cost accountants revisit their apportionment bases periodically rather than treating them as a one-time setup.

Finally, the distribution summary sets up the next stage of the costing process: absorption, where departmental overheads are finally applied to jobs, products, or services using a predetermined rate. None of that later work is reliable unless the distribution summary itself was built on sound allocation and apportionment logic.

What do you think? If a service department like maintenance starts serving an outside client in addition to the factory’s own departments, how do you think that should change the way its costs are apportioned internally? And when a company frequently changes its apportionment basis, does that make the distribution summary more accurate or harder to compare year on year?

References

1. https://www.yourarticlelibrary.com/cost-accounting/overheads-cost-accounting/allocation-and-apportionment-of-overhead-to-cost-centres/55631
2. https://egyankosh.ac.in/bitstream/123456789/104837/1/Unit%209.pdf
3. https://www.financestrategists.com/accounting/cost-accounting/overhead-costing/
4. https://theintactone.com/2024/08/16/absorption-of-overheads-primary-and-secondary-distribution/
5. https://www.superfastcpa.com/what-is-secondary-distribution/
6. https://www.accountingnotes.net/cost-accounting/overheads/apportionment-of-overheads-cost-accountancy/4663