Calculate promotion break-even volume
Estimate how many extra orders cover a discount.
The scenario
An offer drops contribution per order from $30 to $20. The store usually sells 100 units.
Baseline contribution is $3,000. At $20 each, 150 units are needed to match it before extra advertising or labor costs.
Apply it to your own work
Calculate baseline contribution first, then divide by expected promotion contribution. Include costs that change with volume and plan a realistic inventory limit.
Include the cost of announcing the sale
If the promotion also requires $300 in additional media, you need $3,300 of pre-media contribution. At $20 per unit, the new threshold is 165 units. Round required units up when the calculation produces a fraction.
Compare that threshold with confirmed available inventory and the average order quantity. If you can fulfill only 140 units, the current discount and spending plan cannot match the baseline in this scenario.
What to watch for
A promotion can pull purchases forward from next month. Inspect contribution across a wider period before repeating it.
Check whether the operation can fulfill the target
If the break-even target is 150 orders but inventory supports only 130, contribution reaches at most $2,600 at $20 per order before extra costs. Raising the media budget does not solve that fulfillment ceiling.
Model discount depth, available stock, and staffing together. Recalculate when an extra fee or shipping subsidy lowers per-order contribution. Compare realized results across the promotion and the weeks that followed to look for purchases moved forward.
Try a related tool
Compare revenue per advertising dollar with the return needed to cover ad spend. Enter net revenue and contribution margin before ads.
