How Much Margin Can You Give Away Before a Promotion Stops Making Sense?
A promotion can give away only as much contribution as the genuinely incremental demand and other credible benefits repay. Measure the discount on baseline customers as a cost of the offer. Then compare the total promoted outcome with what would plausibly happen without it.
Start with the sales you would make anyway
Assume the comparable non-promotional period would produce 500 orders at $80 net revenue each. Variable costs are $50 per order, including the defined product, transaction and fulfillment costs. Baseline contribution is $30 per order, or $15,000.
A promotion reduces realized revenue to $74 and leaves the $50 cost stack unchanged. Promotional contribution becomes $24 per order. The discount sacrifices $6 on every baseline order exposed to the offer, or $3,000 across the original 500 orders.
Those assumptions simplify cost behavior. If a percentage fee falls with revenue, reflect the saving; if the offer raises fulfillment or acquisition cost, include that increase. The retained $24 must represent the actual scenario rather than a price-only shortcut.
Make the extra orders repay both the discount and the campaign
Suppose the campaign also costs $1,000 beyond the per-order cost stack. The promoted result must generate $16,000 contribution before that fixed campaign expense to preserve the baseline $15,000.
At $24 per promotional order, the hurdle is 666.667 orders, or at least 667 whole orders. That is a 33.4% lift over the baseline. A 25% lift to 625 orders creates $15,000 before the campaign cost and only $14,000 afterward, leaving the business $1,000 worse.
| Promotional orders | Contribution before campaign | After $1,000 campaign | Change vs baseline |
|---|---|---|---|
| 600 | $14,400 | $13,400 | −$1,600 |
| 625 | $15,000 | $14,000 | −$1,000 |
| 667 | $16,008 | $15,008 | +$8 |
| 750 | $18,000 | $17,000 | +$2,000 |
The hurdle is sensitive to the baseline. If only 400 orders would have occurred without the offer, the incremental case is stronger. If a seasonal peak would already have produced 650 orders, the apparent lift may be mostly unrelated to the discount. Estimate the counterfactual using credible comparable evidence.
Keep redemption and eligibility in the discount budget
A promotion shown to every customer may not be redeemed on every order. Model eligible orders, actual redemptions and the associated basket economics separately when those differences are material. Applying the full discount to all orders can overstate leakage, while applying it only to incremental orders can understate it.
Suppose an offer is limited to a product group that contributes only part of a mixed basket. The concession reduces that group’s revenue, but order-level fulfillment may remain largely unchanged. Allocate the discount and service costs consistently rather than charging the complete basket cost to each promoted item.
Minimum-spend offers can change basket composition. An apparent increase in AOV may include low-contribution add-ons, extra package weight or purchases pulled forward. Recalculate retained contribution for the observed basket, not merely the amount above the threshold.
Record exclusions, redemption rules and campaign costs before launch. A forecast based on one offer cannot validate a materially broader offer introduced during execution. When the mechanics change, update the economic comparison and the expected hurdle so the team does not judge the final promotion against assumptions that no longer describe what customers received.
A discount budget is a maximum, not a recommendation
Suppose management believes 700 promotional orders are credible and wants to preserve $15,000 baseline contribution while paying the $1,000 campaign cost. Required contribution per order is $16,000 divided by 700, or about $22.857.
With the simplified $50 variable cost, realized revenue must be at least $72.857 per order. Compared with the $80 baseline price, the mathematical maximum discount is about $7.14, or 8.93%, before any additional profit requirement or uncertainty allowance.
That ceiling assumes the 700 orders actually occur at the chosen discount and cost structure. It is not a reason to immediately discount to the limit. A smaller concession that produces similar demand would preserve more contribution, while weak evidence should justify a wider cushion.
Check whether the promotion borrows sales from later
Customers can advance purchases they would otherwise make next week or next month. The promoted period then looks stronger while the following period weakens. Include a suitable post-promotion window when timing displacement could be material.
The offer can also shift customers from a full-price product to a discounted substitute. Measure the lost contribution on the displaced product, not only the promoted SKU’s growth. A basket-level or category-level view may be more useful than an isolated item report.
Repeat purchase can improve the economics, but count it only with credible evidence and timing. Do not add a full lifetime-value estimate to every newly attributed customer while ignoring acquisition overlap, future service costs or uncertainty.
Use a different comparison for stock recovery
Demand generation
Compare with the credible no-promotion contribution, including baseline discount leakage and campaign cost.
Inventory recovery
Compare net cash recovery with feasible alternatives, including holding, later markdowns and disposal. Original full-price contribution may no longer be achievable.
Customer development
Evaluate incremental cohort contribution over a defined horizon, with repeat behavior and retention costs supported by evidence.
A promotion that fails a short-term contribution test may still serve a valid inventory-recovery purpose. That purpose should be explicit before launch. Otherwise the team can rationalize a weak demand campaign afterward by changing the definition of success.
For clearance, the Dead Stock lesson explains why recoverable cash and accounting cost need separate treatment. For ordinary offers, the Discount Strategy lesson helps connect the concession with its commercial objective.
Set the launch and stop conditions in dollars
Record the baseline, expected orders, realized revenue, variable costs, campaign spend and observation window. Assign a maximum downside and the evidence required to extend the offer. Monitor stock and service so operational failures do not confound the test.
Review actual contribution after refunds and delayed costs develop. Distinguish a correct arithmetic model with a wrong demand assumption from a data-quality problem. Both require correction, but they lead to different next actions.
Use the Discount Calculator for the price change and the Profit per Order Calculator for retained economics. Neither calculator establishes how many incremental orders the promotion will create.
Protect the baseline contribution before celebrating the lift.
The example needs at least 667 orders to preserve the original $15,000 after campaign cost. Set the discount ceiling from a credible demand response, account for sales that would occur anyway and keep a cushion for uncertainty. More promotional sales are useful only when the full comparison supports the offer.
Check the retained rate with the Contribution Margin Calculator before approving the promotion budget.
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