> ## Content Index > Fetch the complete content index at: https://conversion.club/llms.txt > Use this file to discover other available public pages before exploring further. # What Does a Promotion Really Earn You, Margin Included? - URL: https://conversion.club/playbook/what-does-a-promotion-really-earn-you-margin-included/ - Published: 2026-10-01T20:36:46.000Z - Updated: 2026-10-19T20:26:11.000Z - Description: Often less than today's revenue figure suggests. A promotion pays off only if the extra volume makes up for the margin you give away on every sale, including the ones you would have made at full price. - Author: Jeremie Werner - Tags: Increase average order value, #playbook, Cart Often less than today's revenue figure suggests. A promotion pays off only if the extra volume makes up for the margin you give away on every sale, including the ones you would have made at full price. --- ## The benchmark The math comes down to one division. The volume you need during the promotion equals [the unit margin](https://conversion.club/playbook/how-do-you-calculate-the-contribution-margin-of-an-order/) before the discount divided by the unit margin after the discount. Take a hypothetical product that sells for €100 before tax and costs you €60, leaving you a €40 margin. | Discount | Margin left per unit | Sales needed to keep the same total margin | | -------- | -------------------- | ------------------------------------------ | | 10% | €30 | 1.33 times the usual volume | | 20% | €20 | 2 times | | 30% | €10 | 4 times | | 40% | €0 | no volume is enough | We read a discount as a percentage of the price, but it comes out of the margin in full. With a 40% margin, a 20% discount takes half of it. That's why the last column climbs so fast, and even faster on your lowest-margin products. --- ## The rule Set the target volume before the promotion, product by product, and compare it with what your past promotions actually delivered. If your history shows you never reach it, skip the promotion or choose [a shallower discount](https://conversion.club/playbook/how-to-build-a-promotional-calendar-without-betting-everything-on-discounts/). But you still have to be able to trace, after the fact, what the discount cost on each product. In a meeting devoted to this one topic, the person who manages the numbers at a brand the authors work with put it this way: > "If I decide to pull my revenue by SKU today, I'll get revenue including VAT, and I have no way of tracking the discount that was granted based on the product ordered." We were around the table with the integrator for their accounting software, and the fix meant changing the export, a project that needs to be planned several weeks before the promotion. --- ## The steps 1. Margin after discount. Calculate it product by product, from actual cost. In Shopify, the margin shown on the product page in the admin is calculated at full price, while the margin reports account for discounts and refunds, only for sales where the cost per item was entered at the time of sale. 2. Break-even volume. Work it out from the table, then set it against your best past promotion. 3. The measurement window. Track total margin over four weeks: the two weeks before, the promotion, then the two weeks after. 4. [Returns](https://conversion.club/playbook/how-much-does-a-return-really-cost/). Count them separately, because they arrive after the promotion ends and eat into a margin your report had already announced. 5. [The customers you acquire](https://conversion.club/playbook/what-ltv-to-cac-ratio-should-you-aim-for-and-what-can-your-site-change/). Look at what they buy again within the year. At a fashion brand the authors work with, cohorts acquired at full price were worth more over time than those acquired during the soldes, which matches what we described in [our essay on dependence on soldes](https://conversion.club/have-sales-become-a-prerequisite-for-selling-online/). 6. The sentence for leadership: > "For this 20% discount to earn as much as a normal week, we need to double our unit sales, and our best past promotion increased them by X%." --- ## The trap The trap is judging the promotion on its own days. Some of the sales were simply pulled forward, by customers who would have bought the following week at the normal price, and [the dip that follows](https://conversion.club/playbook/how-do-i-get-my-site-ready-for-the-winter-sales/) is part of the result. People also forget that bringing in traffic can cost more during a promotion. In one of the same fashion brand's markets, acquiring a new customer cost about €240 in the month of the summer soldes, versus €50 to €100 the rest of the year. Our read is that every brand is chasing the same attention in the same weeks. This [full acquisition cost](https://conversion.club/playbook/how-much-does-my-acquisition-cost-drop-if-my-conversion-rate-rises-10/), including advertising, tools and salaries, belongs in the break-even volume calculation, alongside the discount. #### Sources - [Profit reports, full-price margin and margin net of discounts (Shopify Help Center)](https://help.shopify.com/en/manual/reports-and-analytics/shopify-reports/report-types/default-reports/profit-reports?ref=conversion.club)