Free calculator · Black Friday is 27 November
What your BFCM discount actually costs you.
Your COGS does not shrink when you discount, so contribution always falls faster than revenue. On a $100 order at 35% COGS, a 25% promotion cuts revenue 25% and contribution 45%, and takes the CAC ceiling down with it. Your own numbers will land somewhere else, which is the point. Four numbers, thirty seconds, and you will know the deepest discount your margin can carry.
Your discount ceiling
The calculator runs in your browser. Your numbers stay in this tab and are never sent to us.
Open your full ceiling report.
You have the headline. The report has the number you came for. It opens on the next page.
- The deepest discount your margin can actually carry
- Your contribution at every depth from 0% to 40%, and your CAC headroom at each one if you entered a CAC
- Your modeled breakeven ROAS at the depth you are planning
Your report opens on the next page. No spam, and you can unsubscribe in one click.
Why the discount costs more than the discount
Every other number in your business moves when you discount. Your cost of goods does not.
You buy the unit for the same price whether you sell it at full price or at 30% off. So the discount does not come out of revenue evenly. It comes almost entirely out of contribution, which is the only pot that pays for acquisition.
Here is what that does on a $100 order at 35% COGS, with fulfilment, fees and returns at the defaults above. This example is illustrative. Your own numbers are what the calculator uses.
| Discount | Revenue | Contribution | After a $40 CAC | Orders to stand still |
|---|---|---|---|---|
| 0% | $100.00 | $51.00 | +$11.00 | 1.00x |
| 15% | $85.00 | $37.20 | -$2.80 | 1.37x |
| 25% | $75.00 | $28.00 | -$12.00 | 1.82x |
| 40% | $60.00 | $14.20 | -$25.80 | 3.59x |
Two things in that table are worth sitting with.
This brand goes underwater at 15% off, not 25%. The depth that breaks you is almost always shallower than the one you were planning, and nothing in a dashboard tells you where it is.
At 25% off you need 82% more orders than not running the promotion at all, purely to match the contribution you would have made by doing nothing. That is not a target. That is the cost of entry.
And the breakeven ROAS moves with it. The same brand needs 1.96x at full price and 2.68x at 25% off, in the week auction prices are at their highest.
What to do with each result
- ✓GO. Your depth sits inside your ceiling. The question worth asking is what your remaining headroom buys as a gift or a free-shipping threshold instead, because both cost you COGS rather than revenue.
- ✓CAUTION. The promotion pays, but only if volume carries it, and BFCM is when volume costs most. Change the shape before you change the depth.
- ✓RESTRUCTURE. Every new customer acquired during the promotion loses money. This is arithmetic rather than an opinion, and it is the one result worth a conversation before you commit stock and spend.
One line of housekeeping, because you should know where our thresholds come from. RESTRUCTURE and the order multiple are pure arithmetic from your own inputs. The CAUTION line sits at a 1.5x order multiple, and that one is a threshold we chose rather than one your numbers produced.
Already at $1M+/year and spending $30K+/month on ads?
The ceiling is arithmetic. Operating inside it is not.
This page tells you the depth your margin can carry. It cannot tell you whether your tracking is reporting the truth during a promotion, whether branded search is absorbing demand the promotion created, or how to run daily decisions across a five-day window. On a free 30-minute call we sanity-check your numbers against your P&L and name your most likely constraint live. Diagnosis before spend.
For brands at $1M+ per year spending $30K+/month on ads. 8 strategy calls a week.
Who built this
Andrej Tuma, HoloGrowth.
Andrej founded and runs HoloGrowth, a growth advisory for 7- and 8-figure DTC brands, which has managed $8.8M in Meta ad spend over the last 180 days as of 30 June 2026, across 50+ DTC brands.
This calculator is the first thing we compute when a brand asks us about a promotion, and it is the reason we say no to some of them.