Making Plant Shut Down Decisions with Relevant Costs

A factory running at a loss is not always a factory that should close. Before pulling the plug, management accountants ask a sharper question: will we lose more by continuing to operate, or by shutting down and reopening later? This is the essence of a plant shutdown decision, and it hinges entirely on relevant costs rather than the total numbers sitting in the income statement.

When does a shutdown decision come up? 🔗

Shutdown decisions surface during unfavourable market conditions such as a demand slump, a raw material shortage, a seasonal dip, or a temporary disruption in supply chains. The plant is still capable of producing, but at current sales volumes, it cannot even cover its own costs. The management then has to choose between two unattractive options: keep running at a loss, or shut down temporarily and restart once conditions improve.

This is different from a permanent closure. A temporary shutdown assumes the business intends to resume operations, so the analysis must also account for the costs of starting up again. As the Corporate Finance Institute explains, a firm reaches its shutdown point when continuing production would generate higher losses than stopping it, making the short-run comparison purely about minimising loss, not maximising profit.

Relevant costs: separating what changes from what doesn’t 🔗

The core principle in this kind of decision-making is simple: only costs that change depending on the choice made are relevant. Costs that will be incurred regardless of the decision add no value to the analysis and should be set aside. AccountingTools frames this well, noting that when a business considers shutting down, the only costs that matter are the ones specifically eliminated as a result of that decision.

In a plant shutdown scenario, fixed costs split into two categories that drive the entire analysis.

Avoidable fixed costs: the ones you can actually save 🔗

Avoidable fixed costs, also called escapable costs, stop the moment the plant shuts down. They represent genuine cash savings and make the case for shutting down stronger. Common examples include:

• Temporary or casual staff salaries: Workers hired on short-term contracts can be let go without breaching any commitment.
• Salesmen’s commissions and incentives: If there’s nothing to sell, variable sales costs tied to output disappear too.
• Certain utility and consumable costs: Power, water, and supplies tied directly to running the production line.

These costs are the ones a manager can genuinely control through the shutdown decision, which is why they sit at the centre of the calculation.

Unavoidable fixed costs: the ones that keep ticking 🔗

Unavoidable, or inescapable, fixed costs continue whether the plant runs or stays idle. They are irrelevant to the decision itself, even though they still appear on the books. Typical examples are:

• Depreciation: This is an accounting allocation of a past investment, not a fresh cash outflow, so it does not change because a machine is idle. The ACCA’s technical guidance on relevant costing is explicit that depreciation involves no cash flow and depends on decisions already made in the past.
• Rent and lease payments: Unless the company can sublet the premises or renegotiate the lease, rent keeps accruing.
• Insurance premiums: Property and liability cover typically continues to protect assets even during idle periods.
• Salaries of permanent staff and interest on borrowings: These obligations don’t vanish just because production has paused.

Because these costs are unaffected by the decision, they should never influence whether the plant shuts down.

Reopening costs: the price of starting again 🔗

A temporary shutdown is rarely free to reverse. Restarting a plant after an idle period usually involves costs such as re-hiring and retraining workers, servicing machinery that has been sitting idle, restocking raw materials, and re-establishing supplier and distributor relationships. Since these costs occur only because the plant was shut down and needs to restart, they are treated as part of the unavoidable cost base for the purpose of this decision, because they must be recovered before shutting down starts saving any real money.

The shutdown point: where the numbers draw the line 🔗

To translate this into a decision rule, management accountants calculate the net avoidable fixed cost, which is the portion of fixed costs that shutdown genuinely eliminates after accounting for reopening costs:

Net Avoidable Fixed Cost = Total Fixed Cost − (Unavoidable Fixed Cost + Reopening Cost)

This figure is then used to calculate the shutdown point, the level of activity at which contribution just covers the avoidable fixed costs. Below this point, shutting down reduces the loss; above it, continuing to operate is the better choice. As study material from the Indian Accounting Association puts it, if demand falls short of the shutdown point, the resulting loss gets capped at the unavoidable fixed cost by stopping production, whereas continuing below that level adds an unrecovered avoidable cost on top.

Shutdown Point (in units) = Net Avoidable Fixed Cost ÷ Contribution per unit

Working through a shutdown decision 🔗

Consider a mid-sized components plant facing a temporary demand slump. Here’s how the numbers might look for a month:

If expected sales fall below 13,000 units for the period, the plant loses less money by shutting down temporarily than by continuing to run. If expected sales stay above that mark, operating at a reduced scale is still the better option, even though the plant is technically making a loss, because it’s still recovering more than its avoidable costs and chipping away at the unavoidable ones.

This is precisely why a loss-making plant should never be shut down purely on the basis of the bottom line. The ACCA’s worked example on shutdown decisions makes a similar point about production lines: closing one down can look attractive on paper because of cost apportionment, yet the actual cash impact often shows that the revenue lost outweighs the costs saved.

Shutdown of a plant vs dropping a product line 🔗

It helps to distinguish a plant shutdown from discontinuing a single product. When one product line is dropped, its share of fixed costs can usually be reallocated across the remaining products, so the business doesn’t necessarily absorb that cost as a pure loss. A full plant shutdown works differently, since the fixed costs that remain after the plant stops producing become a straightforward loss for the entire concern, with nothing left to reallocate them to.

The same logic applies when evaluating a business segment or branch rather than an entire plant. As a breakdown of relevant costing for segment decisions shows, the right approach is to look at the segment’s own contribution margin rather than the overall net result, since allocated costs from head office often make a genuinely profitable unit appear to be a loss-maker.

What managers should watch beyond the numbers 🔗

The shutdown point gives a clear financial threshold, but real decisions rarely stop at arithmetic. A few qualitative factors deserve equal weight:

• Loss of skilled workforce: Trained employees who find other jobs during the shutdown may not return, raising future hiring and training costs.
• Customer relationships: A shutdown can push buyers toward competitors permanently, not just for the shutdown period.
• Market re-entry difficulty: Rebuilding distribution networks and brand presence can cost more than the shutdown ever saved.
• Fixed asset condition: Idle machinery can deteriorate faster than expected, inflating actual reopening costs beyond the estimate.

A sound shutdown decision, therefore, combines the quantitative shutdown-point analysis with a realistic view of these operational risks before the final call is made.

What do you think? If you were managing a plant with rising temporary staff costs but long-term lease commitments, how would you weigh the risk of losing skilled workers against the guaranteed short-term savings from shutting down? And how far into the future would you look before deciding a “temporary” shutdown is worth the reopening costs?

References

1. https://corporatefinanceinstitute.com/resources/management/shutdown-point/
2. https://www.accountingtools.com/articles/what-is-a-relevant-cost.html
3. https://www.accaglobal.com/uk/en/student/exam-support-resources/fundamentals-exams-study-resources/f5/technical-articles/relevant-costs.html
4. https://indianaccounting.org/downloads/econtent/Cost%20and%20Management%20Accounting%20-Marginal%20Costing.pdf
5. https://egyankosh.ac.in/bitstream/123456789/84042/3/Block-5.pdf
6. https://fitsmallbusiness.com/relevant-costs-for-decision-making-accounting/