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Most ecom founders know their ROAS. Very few know their actual contribution margin.
Plug in your numbers from Meta, TikTok, Google, and Amazon. See the truth on every channel: contribution margin, CAC, LTV:CAC, and break-even ROAS. The numbers your CFO would run for you, in two minutes.
- Built by the CFO team behind 25+ ecom brands doing $1M to $50M+.
Here's what most ecom dashboards won't tell you.
Your ad platforms report ROAS. Shopify reports gross sales. Amazon reports referral fees. None of them tell you what actually matters: how much money you keep after every variable cost is paid.
That number has a name. Contribution margin. It’s the dollar amount left after COGS, shipping, fulfillment, processing fees, returns, platform fees, and ad spend. It’s the only number that tells you whether a channel is funding your business or quietly bleeding it.
Most founders I work with can quote their ROAS to one decimal place. Almost none of them can tell me their contribution margin by channel. That gap is where money disappears.
Four numbers. By channel. In two minutes.
You bring the data. The calculator does the math. Here is exactly what comes out the other side.
01
Contribution margin per channel
The dollar amount you keep after every variable cost on Meta, TikTok, Google, and Amazon. Both before and after ad spend, so you can see what each channel is really worth.
02
CAC and LTV:CAC by channel
True customer acquisition cost per channel, plus the lifetime value to CAC ratio. The leading indicator most ecom founders look at once a quarter and should be looking at every month.
03
Break-even ROAS per channel
The ROAS at which a channel stops making you money on a contribution basis. The 3x ROAS rule of thumb is fine. Your actual number is better. We give you yours.
04
A verdict on every channel
Scale up. Healthy. Marginal. Underwater. A one-line read on each channel based on its own LTV:CAC and post-ad contribution. So you know where the next dollar should go.
CFO Expertise · Free Tool
DTC Contribution Margin Calculator
Pull your last 30 days. Plug them in. The math runs as you type.
CFO Expertise · Free Tool
DTC Contribution Margin Calculator
Plug in your numbers from Meta, TikTok, Google, and Amazon. See your true contribution margin, CAC, LTV:CAC, and break-even ROAS by channel. No theory. Just the math you should already be running every month.
Step 1. Your unit economics
These apply across every channel. Best to pull from your last 30 days.
Step 2. Your channels (last 30 days)
Pull these from your ad platforms and Shopify/Amazon. Zeroes are fine for channels you don't run.
Your results
PreviewBlended revenue
$0
Blended contribution margin
$0
0%
Blended CAC
$0
Blended LTV:CAC
0.0x
| Channel | Revenue | Contribution $ | CM % | CAC | LTV:CAC | Break-even ROAS | Verdict |
|---|
Unlock the full breakdown
Get the full per-channel report: contribution margin %, CAC, LTV:CAC, break-even ROAS, and a one-line verdict on each channel. Plus a printable PDF you can drop in front of your team.
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What your numbers are telling you
Want a CFO to read these numbers with you?
I'm Jarrod Souza. I run point on 25+ DTC brands doing $1M to $50M+. Book a free 30-minute call and I'll walk through your channels with you. No commitment. No retainer. Just a straight conversation about your numbers.
Book my free CFO consultBuilt for ecom founders who want the truth on their numbers.
Built for
- DTC and Shopify brands doing $1M to $50M+ per year
- Amazon sellers who suspect their ACoS is hiding their real margin
- Founders making channel-mix decisions on gut feel
Not Built for
- Pre-revenue brands or brands under $250k a year
- Service businesses or agencies, the math is different
- Anyone looking for a vanity ROAS dashboard
Three reasons your ROAS doesn't tell you what you think it does.
01
ROAS ignores everything except revenue and ad spend.
A 3x ROAS sounds great. Until you back out 35% COGS, 6% returns, 2.9% processing, $8.50 fulfillment per order, and a 15% Amazon referral fee. Then your “winning” channel is breaking even or losing money.
ROAS measures one thing. Contribution margin measures what’s left. Those are not the same conversation
02
Blended ROAS hides your worst channel inside your best.
Your blended number averages everything together. So a healthy channel running at 5x can mask a TikTok account running at 1.4x and burning cash every day.
By-channel contribution is how you find the leak. Not after the quarter closes. While it’s still happening.
03
LTV:CAC is the number that tells you what to do next
If a channel returns 4x LTV on every dollar of CAC, you spend more there. If it returns 1x, you fix the funnel or pause spend. ROAS can’t tell you that. CAC paired with contribution-margin-adjusted LTV can.
This is the math the calculator runs for you.
I'm the guy who runs these numbers for a living.
Hey, I’m Jarrod Souza. Longtime CFO for ecommerce brands and big names like Michael Hyatt. I run CFO Expertise with my partners Nathan Hirsch and Connor Gillivan, and we serve as the fractional CFO team behind 25+ Shopify and Amazon brands.
I built this calculator out of the same model I drop into every new client engagement. It’s the first thing I look at when a founder says ‘something feels off.’ Nine times out of ten, this is where I find it.
If the numbers surprise you, that’s the point. Numbers are friendly. They tell you exactly what to fix.
15+
Years in ecom finance
25+
DTC and Shopify brands advised
$4M → $40M
Scaled one brand in 4 years
$1M – $50M+
Revenue range served
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Insights & answers
FAQs about Ecommerce CFOS
Find answers to the most common questions eCommerce founders are wondering about.
No. The math runs in your browser. We don't see your numbers and we don't store them. You only share an email if you want the full per-channel breakdown and the printable PDF.
Meta and TikTok numbers come straight from Ads Manager (spend, purchases, purchase value). Google Ads from the cost and conversion value report. Amazon from your seller central total revenue and total ad spend across Sponsored Products, Brands, and Display. Use the last 30 days for a clean read.
Leave the channels you don't run at zero. The calculator skips them in the verdict and gives you the read on what you actually do.
This is a stripped-down version of the contribution margin model I drop into client engagements at CFO Expertise. The full version includes inventory carrying cost, FBA fees broken out by SKU, labor allocation, and a 13-week cash flow rollup. This one covers what you can do in two minutes from your own ad accounts.
Start by looking at where the leak is. Sometimes it's a creative refresh problem. Sometimes it's a CAC problem the channel can't fix. Sometimes it's an offer problem masquerading as a media problem. If you want a second set of eyes on it, book a free call below and I'll walk through your channels with you.
Want a CFO to read these numbers with you?
Book a free 30-minute call. I’ll walk through your channels with you and tell you what I’d do next. No commitment. No retainer required. Just a straight conversation about your numbers.
Or run the calculator first and bring your results to the call.