A discount is usually decided by what sounds competitive: 20% off, a weekend sale, €10 off €50. Almost never is it decided by what the order still leaves after the discount, the product cost, shipping, payment fees and the ads that brought the customer in. Those two decisions can point in opposite directions: a discount that drives the most orders is often the one that drives the least profit.
Discount profit is the calculation that connects them. It asks one question for every discount under consideration: after this price cut, what does the order actually keep, and how many more of them do I need to sell to end the month in the same place?
This guide covers how to calculate the profit left after a discount, why percentage, fixed-amount, threshold and bundle discounts behave differently even at the same average depth, how many additional orders a discount needs to break even, how discounts stack in Black Week, and how to set a discount ladder instead of one flat number.
Admetrics is a marketing measurement and budget platform for ecommerce and DTC brands. We work out the profit left after costs and returns on every order, at every discount a brand runs.
Key takeaways
- A discount cuts price but not cost. On an €80 order with €40 of product cost, 30% off removes 60% of gross profit, not 30%.
- Break-even volume grows faster than the discount. Doubling a discount from 15% to 30% roughly triples the extra orders needed to keep the same profit, in a typical cost structure.
- Not all discounts of the same average depth cost the same. A flat 20% off and a free-shipping threshold that nets out to 20% behave very differently, because one takes margin on every order and the other only on baskets near the threshold.
- Fixed-amount discounts punish small orders and reward large ones. €10 off is 25% on a €40 order and 5% on a €200 one.
- Stacked discounts compound, they don't add. 20% off plus a 10% code is 28% off, not 30%, but the margin hit is still larger than either alone.
- A discount ladder beats one flat number. Setting depth by product margin, not by campaign, protects thin-margin SKUs without underselling the ones that can carry a deeper cut.
What discount profit actually measures
Discount profit = net revenue after discount − product cost − fulfilment, shipping and payment fees − expected returns
It is contribution margin, CM2, calculated at the price the customer actually pays rather than at full price. Our contribution margin guide covers the layers in full; this guide applies them specifically to the question of what a discount does to each one.
The reason this needs its own calculation, rather than just applying a percentage to the margin line, is that most of an order's costs are fixed in euros, not in percentage of revenue. A discount lowers revenue. It does not lower the cost of the product, the box, the label or the card processing fee. Every one of those costs now has to be covered by a smaller number, which is why the effect on profit is always larger than the discount itself.
Why 30% off removes more than 30% of profit
Take a product that sells for €80 and costs €40 to make, with €7 of shipping and fulfilment and €2 of payment fees. At full price, CM2 is €31, or 38.75% of revenue.
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The relationship is not linear. Each additional 10 points of discount removes a bigger share of what was left, because the fixed costs stay at €49 while the shrinking revenue has to absorb them. At 40% off, this product loses money on every single order before a single euro of advertising is spent.
The product's gross margin decides how much room it has. A product with a 60% gross margin (€32 cost on an €80 price) can absorb a 30% discount and still clear €15 of CM2; the 50%-margin product above cannot. This is the basis for discounting by product, covered later in this guide, rather than by campaign.
How many more orders a discount needs
A discount is often justified by "it'll drive more volume." The question discount profit answers is: how much more volume, exactly, to end up with the same total profit as not discounting at all.
Break-even volume increase = full-price CM2 ÷ discounted CM2 − 1
Using the €80 product above, full-price CM2 is €31:
The curve is not gentle. Going from 10% to 20% off roughly triples the extra volume required, and going from 20% to 30% more than triples it again. This is the single most common reason a "successful" Black Friday, measured in units sold, turns out to be a flat or negative month in profit: the volume did increase, often by 50 or 80%, but the discount needed a 207% or 343% increase just to stand still.
Run your own product's numbers in the free discount profit calculator, and compare several depths side by side before picking one.
Not every discount of the same depth costs the same
"20% off" is usually shorthand for a percentage discount, but several structures can average out to a similar depth while taking margin very differently.
Worked comparison: 20% off vs. a €12 fixed discount
Same €80 product, same €49 of fixed costs, two offers that both look like "about 20% off" at this price point:
At this single order value they look similar, but the fixed discount keeps 27% more margin per order, because its euro cost doesn't scale with price the way a percentage does. The difference reverses on a €40 order: there, €12 off is a 30% discount, deeper than a flat 20% would be. Fixed-amount discounts are therefore a basket-size lever as much as a price lever — they quietly reward customers for buying more, and quietly punish the brand when average order value is low.
How discounts stack
Black Week commonly runs a site-wide sale alongside email codes, loyalty discounts and affiliate commissions, and these do not add.
Combined discount = 1 − [(1 − discount 1) × (1 − discount 2) × …]
A 20% site-wide sale plus a 10% email code is not 30% off. It's 1 − (0.80 × 0.90) = 28% off — close, but every point matters at this depth, and the gap widens as the discounts get bigger. 30% plus 20% is not 50%; it's 44%.
The practical implication: if a site-wide Black Friday discount is already at 30%, every stackable code or affiliate commission on top of it needs its own margin check, because the product can tip into a loss well before the headline discount would suggest.
Case study: ESN cut customer acquisition cost 70% without discounting deeper
The default move when orders slow is to discount harder. ESN, the sports nutrition brand run by The Quality Group, took a different route when it hit a growth plateau while running over 13 ad platforms, hundreds of campaigns and thousands of creatives — with Black Friday alone producing up to 95,000 orders in a single hour.
Instead of a deeper site-wide discount to push more volume, ESN replaced last-click attribution with a U-shape multi-touch model inside Admetrics, so budget could be credited to what actually won a customer rather than whichever touchpoint happened to be last. Admetrics' AdPilot then automated the hourly micro-decisions — scaling, cutting and pausing ad sets against real CAC and margin, not platform-reported ROAS — that a manual team could never keep up with across that many platforms and creatives.
Within 12 months: cost per new customer fell over 70%, revenue from paid social rose 81%, and the team now ships 75–100 ad creatives a week with roughly 8 in 10 decisions automated.
Admetrics helped us overcome scaling challenges and set a new benchmark for paid ads. The AI integration solved attribution complexity, so we slashed CAC by 70% and boosted revenue by 81%.
— Paul Keil, Team Lead Performance Marketing, ESN
The lesson for discount planning specifically: a 70% fall in cost per new customer does far more for margin than almost any achievable discount depth, and it came from spending existing budget more precisely rather than from cutting price further. Before reaching for a deeper discount to protect volume, it's worth asking whether the budget behind it is actually finding the right customers in the first place.
Building a discount ladder instead of one flat number
Most Black Friday plans set one discount for the whole site, or one per category. A margin-based ladder sets it per product, from the product's own cost structure.
- Calculate full-price CM2 ratio for every product (or at least every product you plan to promote).
- Set a CM2 floor — the minimum amount, not percentage, each order must still clear after ads. This should roughly track your average cost per order.
- Solve for the maximum discount each product can take while staying above that floor.
- Group products into two or three discount tiers rather than calculating one bespoke number per SKU, for simplicity on the site and in ads.
This is close to how Casper structures its own Black Friday pricing: tiered discounts by product, with the deepest percentage cuts reserved for its higher-margin premium lines rather than applied as one number across the whole catalogue. The effect is a headline offer ("up to $800 off") that reads as aggressive while the average margin across the sale holds up better than a flat site-wide percentage would.
Discount profit in Black Week
- Set the floor before the offer, not after. Decide the CM2 floor per product tier in the weeks before Black Friday, so the discount depth is chosen from cost data, not matched to a competitor's headline.
- Re-check stacking the moment a second promotion is added. Affiliate commissions, loyalty points and email codes all compound with the site-wide sale; check the combined figure, not each discount alone.
- Watch discounted CM2 against your break-even ROAS and MER, which rise with every point of discount. Our MER vs ROAS guide and ROAS calculator guide cover how.
- Watch returns separately by discount depth. Heavily discounted categories, especially apparel, often see higher return rates, which erodes the already-thin CM2 further.
Our Black Friday preparation guide covers the full plan, from goals through to the January review.
Discount profit calculator
Try it with your own numbers: the free discount profit calculator shows what a given discount keeps per order, after product, shipping, fees and returns, and how many more orders it needs to break even against full price. For the underlying margin layers, use the contribution margin calculator.
Common mistakes
- Treating discount % as a proxy for profit impact. The relationship is not linear; a 40% discount is not "twice as costly" as 20%, it's often the difference between profit and loss.
- Comparing discounts of different types by headline depth alone. A fixed-amount discount and a percentage discount at the "same" rate behave completely differently depending on order value.
- Adding stacked discounts instead of compounding them. The actual combined discount is always slightly lower than the naive sum, but the margin hit is still real and still needs its own check.
- Setting one discount for the whole catalogue. Products with different margins can sustain very different discounts; a single site-wide number either under-discounts the strong products or loses money on the weak ones.
- Reaching for a deeper discount before fixing acquisition cost. As ESN's case shows, cutting cost per new customer can protect margin far more than cutting price does.
- Ignoring returns by category when setting the floor. A discount that clears CM2 before returns can still lose money once an above-average return rate is factored in.
See discount profit on every order, automatically
Admetrics calculates CM2 for every order at the price actually paid, including every stacked discount and code, with returns factored in. You see which products and campaigns are still profitable at the discount you're running, while you can still change it.
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FAQ
How do you calculate discount profit?
Take the price after the discount, then subtract product cost, fulfilment and shipping, payment fees, and expected returns. What's left is the order's contribution margin at that discount, which is what "discount profit" measures.
Does a 20% discount cost 20% of profit?
No, usually much more, because product cost, shipping and fees stay fixed in euros while revenue falls. On a product with roughly 50% gross margin, 20% off can remove around half of CM2, not a fifth.
How many extra orders does a discount need to break even?
Divide full-price CM2 by discounted CM2 and subtract 1. For a product that goes from €31 to €15 of CM2 at 20% off, that's roughly a 107% increase in orders just to match full-price total profit.
Is a fixed euro discount better than a percentage discount?
It depends on order value. A fixed discount is a smaller effective percentage on large orders and a larger one on small orders, the opposite of how a flat percentage behaves. Run both through the calculator at your actual average order value.
How do stacked discounts combine?
They compound rather than add: multiply the retained price shares together, not the discount percentages. 20% plus 10% is 28% off combined, not 30%.
Should every product have the same Black Friday discount?
Not if margins vary across the catalogue. A discount ladder, set from each product's cost structure, protects thin-margin SKUs from selling at a loss while letting higher-margin products carry a deeper, more attractive cut.
Is a deeper discount the only way to protect flagging volume?
No. ESN cut cost per new customer by over 70% and grew revenue 81% by fixing attribution and automating budget decisions, without a deeper site-wide discount. Acquisition efficiency is often a bigger lever than price.