A small manufacturer is operating at 60% of its installed capacity. The machines sit idle for much of the shift, the staff gets paid regardless, and the factory rent is the same every month, whether it is running at full capacity or not. Then an order comes in from a new customer willing to pay R$ 85 for a part the company normally sells for R$ 120.
The most common reaction is to turn it down. R$ 85 is below the list price, and accepting it seems to set a dangerous precedent—the next customer will want the same discount, and the company’s overall margin will collapse. That reasoning makes sense when the factory is operating at full capacity and every production hour must be allocated among competing orders. But when there is spare capacity, that same reasoning costs money.
The right question isn't “does this price cover my total cost?” It's “does this price cover the variable cost and still leave something left over?” If it does, turning down the order doesn't protect your margin—it wastes capacity that would sit idle anyway.
Why Total Cost Is Misleading in This Decision
A product’s total cost includes two fundamentally different components: variable costs, which are incurred only because that specific unit was produced (raw materials, supplies, process energy, commissions), and fixed costs, which the company pays whether or not it sells that unit (rent, administrative payroll, equipment depreciation).
When the factory has idle capacity, fixed costs are already covered by normal production—or will have to be paid anyway, whether or not there is an extra order. An additional order only adds the variable cost of producing that extra unit. At that point, comparing the offered price with the total cost means comparing the wrong figures: it assigns the order a cost it did not cause and that the company will incur anyway.
That’s where contribution margin comes in: the difference between the selling price and the variable costs and expenses associated with that unit. It does not measure whether the product is “profitable” in the full accounting sense—it measures whether that specific sale adds cash after covering the costs it generated. When there is spare capacity, any positive contribution margin is better than leaving the machine idle.
The Calculation That Decides
Take the example of the R$120 item. Suppose its variable production cost is R$70—including raw materials, process inputs, and the labor directly involved in producing that unit. Allocated fixed costs, calculated by spreading rent, depreciation, and overhead across the normal production volume, add another R$30 per item. Together, the total cost is R$100, so a price of R$120 leaves a margin of R$20 per unit on regular sales.
The new customer offers R$85 per unit for a batch of 200 units, outside the regular sales channel and without competing with customers who already pay full price.
Compared with the total cost of R$100, a price of R$85 looks like a loss of R$15 per unit—and that figure is what leads to rejecting the order. Compared with the variable cost of R$70, however, each unit generates a contribution margin of R$15, because the R$30 fixed cost is already covered by normal operations and will not change whether the order is accepted or not.
Across 200 units, that adds up to R$ 3,000 in additional contribution—cash coming into the business to help cover fixed costs, versus R$ 0 if the capacity remains idle. The deciding question is not whether R$ 85 is a good price in absolute terms. It is whether R$ 85 exceeds the variable cost of R$ 70. It does, and the entire difference goes straight to the company’s bottom line.
The conditions that must be met
Accepting less than the full price is not a general rule—it is a conditional decision. Three things must be true at the same time:
- There is genuinely idle capacity. This does not mean “we can squeeze it in”—it means capacity that would sit idle without this order. If accepting the order means turning away another customer who would pay full price, the calculation changes completely: the opportunity cost of the order is not zero; it is the full price you forgo.
- The offered price exceeds the variable cost. Below that, each unit sold adds to the cash loss rather than making a contribution. No sales volume can make up for selling below variable cost.
- The order does not spill over into the regular market. A new customer, a separate channel, a closed lot, a different region—some barrier that prevents a customer currently paying R$ 120 from finding out that the same product is available for R$ 85.
If any of the three conditions is missing, the decision is no longer about idle capacity—it becomes a discount in disguise.
The Risk of Turning an Exception into the Rule
The most common mistake is not accepting the first order below full price—it is doing so without setting limits on the exception or reviewing it once capacity is no longer idle. A one-off order in a month of weak demand is a financial decision about a specific batch. The same order, repeated every month, becomes a second list price—and at that point, it starts competing with the full price rather than complementing it.
That is the opposite of what contribution margin should do: it exists to tie price to a specific market condition (in this case, idle capacity), not to become a fixed number applied to every order, from every customer, all year round. A contribution margin that never changes with factory utilization no longer provides useful information—it has become a habit, just like applying the same margin to completely different products.
In practice, this means reviewing the special price every cycle: is there still idle capacity? Is the customer still separate from the regular sales channel? Does the accepted volume still fit within available production capacity without delaying orders from customers who pay full price? When the answer to any of these questions becomes no, the special price is no longer justified.
Where This Decision Is Really Made
The difference between “accepting this order” and “accepting any order below full price” comes down entirely to calculating the contribution margin correctly, unit by unit and customer by customer—not to a blanket discount rule. REVEMA’s sales price calculator helps you quickly simulate the impact of accepting an order below full price before closing the deal by comparing variable cost, allocated fixed cost, and the offered price side by side.
It is also worth fully understanding the concept of contribution margin before applying this logic to any pricing decision: it is the metric that distinguishes an order worth accepting even below list price from one that only looks good because no one compared it against the right figure.
Idle capacity is not a reason to sell at any price. It is a reason to compare the offered price with the costs the order actually creates, not with costs the company would incur anyway. Rejecting an order that covers variable costs and still generates a positive contribution does not protect margins—it leaves money on the table while available capacity sits unused on the factory floor.
