Relevant costs in special orders
Evaluate a special order with its incremental revenue minus avoidable costs and any contribution lost from displaced sales. Treat idle capacity and constrained capacity as separate cases. An order below full absorption cost can still be profitable, but only under the right assumptions.
Capacity changes the special-order decision
- Start with contribution
- Order units × (order price - incremental unit cost).
- Deduct order-only costs
- Include a dedicated setup or other avoidable costs caused by the order.
- Deduct displaced contribution
- At full capacity, subtract profit lost on the best foregone use.
A positive result supports acceptance only if quality, customer relationships and other constraints are also satisfied.
See the decision
The same order under two capacity conditions
An order requests 800 units at $45. Incremental cost is $29 per unit plus a $2,000 setup. At full capacity, each order unit displaces $15 of regular contribution; at idle capacity it displaces none.
Would this order displace regular sales?
No: idle capacity
800 × ($45 - $29) - $2,000 = $10,800 benefit.
Acceptance improves operating income before qualitative constraints.
Yes: full capacity
$10,800 - 800 × $15 lost contribution = -$1,200.
Reject at this price under the stated capacity assumptions.
Choose the branch that matches capacity. These are alternative cases, not consecutive steps.
The modeled order is attractive with idle capacity and unattractive at full capacity. Capacity is a decision fact, not a footnote.
How to apply these ideas
1. Identify changes
List each cash flow that differs if the order is accepted.
Include special packaging, freight, setup and supervision where added. Exclude a prior design study and unchanged allocated overhead. The label “fixed” does not settle relevance; whether the amount changes does.
Watch for: Including a sunk cost because it appears in the product-cost report.
2. Check capacity
Compare required resources with unused capacity.
An order may fit machine capacity but still consume scarce labor or materials. Identify the actual bottleneck. If regular output is displaced, calculate the contribution lost from the best available alternative use.
Watch for: Assuming idle capacity in one department means no opportunity cost anywhere.
3. Compare alternatives
Keep quantities and time periods consistent.
A one-time setup is added once; a per-unit cost is multiplied by order quantity. Compare acceptance with rejection under the same baseline. Include any reduction in regular sales price only when supported by the case facts.
Watch for: Multiplying a one-time cost by every unit.
4. State the conditions
Separate calculated benefit from commercial risks.
Confirm quality, payment terms, customer relationships and whether the special price sets an unwanted precedent. A conditional recommendation can state the economic benefit and the specific unresolved operational check.
Watch for: Calling the arithmetic an unconditional business recommendation.
Study the topic
Relevant costs in special orders: explanations and applications
Evaluate an additional order under idle, constrained and expandable capacity. The decision-analysis parent explains relevant costs across make-or-buy, shutdown and product-mix decisions.
By MiloPrep editorial team. Original teaching explanations and illustrative cases; official curriculum references are listed below.
Build the order’s own profit statement
Start with the additional units and offered price. Deduct manufacturing inputs, incremental shipping, commissions, customization and order-specific setup or inspection. Include a fixed charge when accepting the order creates it. Exclude unchanged fixed commitments merely allocated to the units. The distinction is change between alternatives, not fixed versus variable.
Check whether the order changes other sales. A customer may substitute the discounted order for regular purchases, or regular customers may demand the same terms. The simple calculation is valid only if the stated assumptions about customer behavior, quality and timing hold. Document those conditions beside the numerical result.
Price the capacity actually sacrificed
Unused capacity has no displaced-sale opportunity cost only when there is no valuable alternative use in the relevant period. At a bottleneck, calculate how much of the scarce resource the order consumes and multiply by the contribution that could be earned from its best feasible alternative. Contribution per unit can be the wrong measure when products use different amounts of capacity.
If overtime, outsourcing or a temporary machine can provide capacity, compare that incremental cost with the opportunity cost of displacing regular production. Choose a feasible capacity plan before deciding on the order. Do not include both the full displacement cost and the full expansion cost if they are alternative ways to fulfill the same units.
| Condition | Relevant addition | Decision check |
|---|---|---|
| Idle capacity with no other use | Order-specific costs only | Confirm demand, quality and capacity facts |
| Binding capacity | Lost contribution from the best displaced alternative | Use the actual bottleneck resource |
| Capacity can be added | Overtime, subcontracting or expansion cost | Compare feasible plans without double counting |
Calculate a conditional minimum acceptable price
Under a simple one-order model, minimum price equals incremental variable cost per unit plus order-specific fixed cost per unit plus opportunity cost per unit. It is an economic indifference price under the stated assumptions, not necessarily the commercial price the company should quote. Negotiation, risk, service obligations and long-run positioning can justify a higher price.
Test the volume and capacity assumptions. A setup cost spread over fewer units raises the minimum unit price. A higher-margin alternative raises the opportunity cost. If uncertainty is material, identify the threshold at which the order no longer improves profit and state which fact should be confirmed before acceptance.
Work it through
Worked example: The same order under two capacity conditions
An order requests 800 units at $45. Incremental cost is $29 per unit plus a $2,000 setup. At full capacity, each order unit displaces $15 of regular contribution; at idle capacity it displaces none.
| Item | Idle capacity | Full capacity |
|---|---|---|
| Order contribution before setup | $12,800 | $12,800 |
| Setup cost | -$2,000 | -$2,000 |
| Lost regular contribution | $0 | -$12,000 |
| Net benefit | $10,800 | -$1,200 |
- 1
Before opportunity cost: 800 × (45 - 29) - 2,000 = $10,800.
- 2
At full capacity: 10,800 - 800 × 15 = -$1,200.
The modeled order is attractive with idle capacity and unattractive at full capacity. Capacity is a decision fact, not a footnote.
Work through the alternatives
More worked cases: relevant costs in special orders
Original teaching scenarios. Each case states its assumptions, shows the working and explains the limits of the conclusion.
Measure opportunity cost in machine-hours
A special order is 500 units at $52, variable cost $30 each, plus a $1,000 setup. Each unit needs two bottleneck hours. Regular production earns $12 contribution per bottleneck hour. All 1,000 required hours would displace regular production.
| Relevant item | Amount |
|---|---|
| Special-order contribution before setup | $11,000 |
| Order setup | -$1,000 |
| Lost regular contribution: 1,000 × $12 | -$12,000 |
| Net change in profit | -$2,000 |
- Order contribution after setup is 500 × (52 - 30) - 1,000 = $10,000.
- Opportunity cost is 500 × 2 × $12 = $12,000. Minimum price = 30 + 1,000/500 + 24 = $56 per unit.
What the result means: Reject at $52 under these assumptions. The order would look profitable if the bottleneck opportunity were omitted.
Practice this topic
Check your understanding
Try each short application before opening its explanation. These are original learning checks, not official exam questions or a score prediction.
1. An idle-capacity order requires 400 units, $18 variable cost each and a $1,200 setup. No other effects occur. What is the break-even order price?
Show answer and explanation
$21 per unit.
18 + 1,200/400 = 21. This is an indifference price, not a required selling strategy.
2. Accepting an order requires renting a dedicated tool for $2,000. Is that cost relevant even though it is fixed for the order?
Show answer and explanation
Yes.
It is a future cost incurred only under acceptance. Fixed costs are not automatically irrelevant.
Questions about relevant costs in special orders
- Should full absorption cost set the minimum price?
- Not automatically for a one-time incremental decision. Unchanged allocated fixed overhead may be irrelevant, while omitted opportunity costs may be crucial. Long-run pricing must still sustain total resources.
- What if there is no outside market?
- Opportunity cost depends on the best forgone use of the constrained resource, which may be another internal product. If there is no alternative use and capacity is idle, it can be zero.
Sources and scope
Curriculum mapping: Part 2, Section C, Business Decision Analysis. The official outline assigns 25% to the entire domain, not to this individual technique. These are selected study notes, not complete curriculum coverage.
Official curriculum references establish scope and expected skills. The explanations, diagrams and numerical cases are independent teaching material from MiloPrep, not official questions or source-validated solutions. Curriculum references checked 2026-10-10.
- IMA Content Specification Outlines (effective September 2024) ↗
Supports: Part 2, Section C, beginning on printed page 11. Domain names, weights and curriculum boundaries.
- IMA Learning Outcome Statements (effective September 2024) ↗
Supports: Part 2 C.2.c-n: opportunity costs and capacity decisions; printed page 24. Curriculum scope, not verification of this original worked example.
Independent US CMA study material. Not affiliated with or endorsed by IMA. This covers management accounting, not medical-assistant certification or the separate ICMAI qualification.