josh whiteThe Margin Math Before the First Ad
Sean Frank recently posted a list that got about 1,000 likes and 52k views. It goes: make good products, make good ads, have a good offer, use a 3PL, run the ads on Meta, take care of customers, repeat. Then "Don't buy a course." You can read it here on X.
It's a good list and I mostly agree with it. But "run the ads on Meta" is carrying a lot of weight, and there's a step that never makes anyone's list. It's knowing what an order leaves you with after everything it costs, so you know what you can pay to get it.
Andrew Jennings, who says he's been running consumer brands since 2012, posted his own version. His first point is the one I want to build on. A good product means a gross margin you can advertise from, with landed cost under 30% of retail price. Below 65% gross margin, he says, Meta will eat the business in year one. I think that's a sensible rule of thumb. I'd also call it the start of the math.
gross margin tells you if the product can carry ads
Gross margin is price minus what the product costs landed, so the unit cost plus freight in and duties. It's how you find out whether the product can carry advertising at all.
It doesn't tell you what you keep from an order. An order has costs that show up after the product does: the discount code, pick, pack and shipping, returns and refunds, and payment fees. What's left after those is contribution margin, and that's the number I'd advertise from.
Here's an example. This is made up and not from any real brand.
A $50 product, and the average order goes out with 10% off, so $5 comes off the top. Landed cost is $15. Pick, pack and shipping is $9. Returns and refunds average $1.50 an order and payment fees are another $1.50.
On paper that's a 70% gross margin, which looks great. After the rest of the order you keep $18, or 36% of the list price. Same product, same order, and about half the margin you thought you had.
set your max nCAC from that number
So what can you pay for a new customer? The term for it is nCAC, what it costs you to get a new customer, and your max nCAC is the most you can pay. If you want the first order to pay for itself, that max is $18, your day one break-even.
Now say Meta is showing you $30 per purchase. If you're looking at gross margin, you see a $35 ceiling and feel fine about $30. If you're looking at contribution margin, every new customer costs you $12 on the first order. Do that 1,000 times and it's $12,000 gone.
A second order can close that gap, and sometimes it should. That's a bet on repeat rate, and I want it to be a bet you made on purpose, using your own cohorts and with cash to carry it. I don't want you finding out in month four. If you want to build in a payback window, I wrote about that in fix your payback math before Black Friday. The short version is that your ceiling is target payback months multiplied by monthly contribution margin per customer.
I think a lot of brands scale into a loss for this reason. The ads report a number that looks fine, the margin they're comparing it to is the wrong one, and the bank account tells them about it later.
the cash part is on the same page
Contribution margin also sits on top of inventory, and inventory is cash that leaves before anything sells. That $15 unit gets bought weeks or months ahead of the order that pays for it.
Jennings puts numbers on it in the same post. For new suppliers he describes stock as paid 20% at order and 80% before it ships, two to three months before it sells, and he keeps the next deposit plus three months of ad spend in the bank. His line is that every brand he's seen die was profitable on paper but ran out of cash. I can't verify his cases, but the shape matches what I'd expect, and it's why I'd put units on hand, the next PO and its due date next to the margin math. Same page, same conversation.
this is one job
Growth sets the ad budget. Ops sets landed cost and shipping. Finance decides which margin counts. When those are three different people, the media buyer works from ROAS, the 3PL invoice never reaches whoever sets the CAC target, and the founder hears about the gap from the bank balance. I run growth, operations and finance as one job for this reason. It's one set of numbers.
If you're a founder, an operator who inherited the ad budget, or an exec trying to read a brand's P&L from the outside, it's the same math. And if you haven't launched yet, it's even better to do it now. Your numbers will be assumptions, which is fine. Write them down, then swap in real ones after the first few hundred orders.
what a part-time version covers
A common worry is "I can't justify a full-time finance or ops hire yet." You probably can't, and you don't need one for this. A part-time version covers a short list:
- Contribution margin by SKU and channel, after discounts, shipping, returns and fees.
- A max nCAC for each, set before the spend goes out.
- How much cash is sitting in inventory and when the next PO is due.
- A weekly look at actuals against those numbers, so ads get adjusted before cash gets tight.
That's it. One person looking at growth, ops and finance together can keep those four things current.
three questions before the next ad dollar
Write these down:
- What does one order leave me after discounts, shipping, returns and fees?
- What's the most I can pay for a new customer, and what payback am I willing to fund?
- How much cash is tied up in stock, and what does the next PO do to it?
If you can answer all three, run the ads. If you can't, that's the work to do first. If you'd like a second set of eyes on it, I'm happy to go through margin by SKU and channel, your max nCAC and the cash tied up in inventory with you. The nCAC & Payback Calculator is free if you want to start on your own, or you can book a call and we'll go through your numbers together.
Example numbers in this article are illustrative, not data from any company. The X post figures were read on Oct 27, 2026. The Jennings figures are his rules of thumb and his own account, not my data.
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