Your agency says you're at a 3x LTV to CAC. It's in your investor deck. Everyone nods.

And yet every month you push spend, there's less cash in the bank.

The 3x isn't exactly wrong. It just hides the two things that decide whether you're making money: what you keep on the first order, and how long it takes to get your ad spend back.

Here's how most brands calculate LTV to CAC, how I do it instead, and what a good number looks like. At the end there's a free calculator you can use on your own numbers.

Meet Harvey Chow (again)

Harvey Chow is the fictional dog brand from my P&L breakdown last week. Dog toys, treats and food, about $10M a year. The numbers are made up, but they're in a realistic range.

This time we're zooming in on one customer.

What is CAC, really?

CAC is your cost to acquire a customer: total ad spend divided by total new customers.

It's blended. It's not your Meta CPA, your Google CPA or your TikTok CPA. It's all your ad spend over all your new customers.

If you sell on Shopify, Amazon and TikTok Shop, you can't perfectly dedupe customers across channels. That's fine. Make a reasonable assumption and you'll still get a solid directional number.

What is LTV (and what isn't it)?

LTV is lifetime value, and it gets misused more than any metric I know.

• It's not your repeat rate. "30% of customers come back" tells you how many, not how much.

• It needs a time frame. A $1,000 LTV over 36 months is a completely different business than a $1,000 LTV over 12.

• It's not a subscription stat. "We keep 80% of subscribers after the first order" says nothing about company LTV if you don't know what share of customers subscribe or what they spend.

So I always look at two numbers together.

LTV in dollars: what a customer spends with you, on average, over a set time frame, including the first order.

LTV lift: how much that grows from the first purchase. Lift captures both how often people come back and how much they spend.

Why both? A $100 12-month LTV sounds fine. But if the first order was $90, that customer only spent $10 more with you all year.

Harvey Chow's first order is $90. By month 12, the same group of customers has spent an average of $180. That's 2x the first order, a 100% lift.

And don't stop at 12 months. Harvey Chow is at $120 by month 3, $140 by month 6 and $180 by month 12. Hold onto those. We need them for cash.

How does everybody calculate LTV to CAC?

Harvey Chow's CAC is $60. Their 12-month LTV is $180.

$180 ÷ $60 = 3.0x.

Sounds good. I've heard brands throw around 4x, and as low as 1x, which honestly scares me.

But there's a lot hiding in that 3x.

What does the 3x hide? The first order.

CAC doesn't tell you if your first purchase made money.

The customer spends $90. CAC is $60. Looks like you made $30.

Not so fast. You have to make the product: $18.70. Pick and pack it: $2.00. Ship it: $4.50. Shopify and payment fees: $1.80. Selling on Amazon or TikTok Shop? Their fees come out here too.

That leaves $63. That's CM1: what you keep after making and delivering the product. (If CM1 is new to you, last week's P&L article explains it.)

Now take out the $60 CAC.

You're making $3 on that first order. About 3%. Not $30.

What does the 3x hide? Margin on every repeat order.

Same problem on the LTV side. That $180 is revenue. You still have to make and ship every repeat order.

So instead of LTV to CAC, I use LTV margin to CAC: take your 12-month LTV, apply your CM1, then divide by CAC.

$180 × 70% = $126.

$126 ÷ $60 = 2.1x.

Not 3x. 2.1x.

For every dollar Harvey Chow spends to get a customer, they get $2.10 back in contribution over 12 months. Their dollar back, plus $1.10.

How long until you get your money back?

This is the second number you need, and it matters most if you're losing money on the first order.

Say Harvey Chow is scaling hard and testing new channels, and CAC climbs from $60 to $80.

On that $90 first order, they keep $63. Now it costs $80 to get the customer. They're down $17 on every new customer's first order.

When do they get the $17 back? From repeat orders:

• Month 1: customers spend another $12. Harvey Chow keeps 70%, $8.40. Still down $8.60.

• Month 2: another $10, keep $7.00. Down $1.60.

• Month 3: another $8, keep $5.60. Up $4.00.

Paid back in month 3.

And at an $80 CAC, 12-month LTV margin to CAC drops to 1.6x ($126 ÷ $80).

What does a good LTV to CAC look like?

For fast-growing 7- and 8-figure brands, I usually see a 12-month LTV margin to CAC around 1.6x.

Much higher, like Harvey Chow at 2.1x, and you might be under-scaling. You could probably spend more.

Much lower, and your CAC is too high, your LTV is too low, or your product margins make it hard.

On payback, I like to see break-even by month 3. The further out you push it, the riskier it gets.

You can play a longer game if you have wholesale, strong investor backing and real conviction in the product. Plenty of brands do. But if you're self-funded, more risk-averse, or still proving your product has the repeat behavior you think it has, stay at a 2- to 3-month payback. You can track it closely and adjust fast.

Which levers move it?

Once you calculate this, you know what you make or lose on the first order, when you get it back, and what a customer is worth at 3, 6 and 12 months. You also know which levers to pull.

On the first order: product margin, fulfillment and shipping costs, platform and payment fees, your offer structure, and your CAC.

On LTV: how often people buy, how much they buy, how many of your products they have in their hands, and how attached they are to your brand.

A lot of this comes down to product. But a lot of it comes down to how you position the product from the very first order.

How do I calculate this for my brand?

I built a free calculator that does all of this math for you.

Make a copy, fill in the orange and yellow cells, and it shows your first-order profit, payback month, and LTV margin to CAC at 3, 6, 9 and 12 months.

What you'll need:

• New customer AOV (gross sales minus discounts, first orders only) from Shopify Analytics. Start with the last 12 months, then try the last 3 months and the last 30 days to see where you are right now.

• Total ad spend for the same periods. All of it: every platform, plus influencer and affiliate costs. The sheet uses aMER, which is new customer revenue ÷ total ad spend.

• Refunds, shipping income, product cost (COGS) and payment processing, each as a % of that AOV.

• Fulfillment and shipping cost per order. Your 3PL and carrier invoices ÷ orders shipped.

• How much more customers spend each month after their first order, from Shopify's customer cohort report. Use at least the last 2 to 3 years of cohorts. If your product, pricing or offer changed a lot, lean on the more recent ones.

I walk through all of this in the video at the top of this post.

Sarah Carusona, DTC growth operator and founder of BA Commerce. I've run 7, 8 and 9-figure P&Ls and work with $5-50M DTC brands.