Every business is a machine. Money goes in one end, customers come out the other. The question every founder and marketer needs to answer: Is your machine printing money or burning it?
The answer is one number. And most companies get it wrong.
Simple formula. Devastating when misunderstood.
Everyone Gets This Wrong
When we audit growth programs, the CAC calculation is wrong about 80% of the time. Not slightly wrong. Catastrophically wrong.
The mistakes are predictable.
They forget costs. CAC isn't just ad spend. It's the salesperson's commission. The marketing automation software. The agency retainer. The designer who made the landing page. If it touched acquisition, it belongs in the number.
They count the wrong customers. If someone found you through word of mouth, they shouldn't count against your paid acquisition costs. Blending everything together hides the truth.
They measure at the wrong time. A lead from January that converts in March shouldn't be matched against March's spend. Timing matters.
The goal isn't the lowest CAC. It's the highest profitable CAC you can sustain at scale.
The Only Ratio That Matters
CAC by itself is meaningless. What matters is how it relates to what a customer is worth.
Here's the cheat sheet:
Below 1:1. You're losing money on every customer. Stop everything.
1:1 to 3:1. You're surviving. Don't scale yet.
3:1 to 5:1. Healthy. Pour on the gas.
Above 5:1. You're probably underinvesting. Spend more.
That last one surprises people. But if your ratio is 10:1, you're leaving growth on the table. You could acquire customers more aggressively and still be profitable.
The Payback Problem
LTV:CAC tells you if the math works eventually. Payback tells you if you'll survive long enough to see it.
Spend $500 to acquire a customer who pays $50/month. Your LTV might look great over three years. But you need ten months just to break even. Can your cash flow handle that? At what scale?
The companies that scale fastest have cracked payback. They monetize quickly. Upsells in the first week. Annual contracts instead of monthly. They don't just optimize CAC. They optimize time-to-money.
What Good Looks Like
The best operators we work with know their numbers cold.
Ask them "what happens if we increase spend 20%?" and they don't guess. They know exactly what that produces, at what margin, with what payback period. They've built a machine they understand completely.
Ask them "which channel should we cut?" and they have a rank-ordered list by efficiency, already updated this week.
Ask them "what's our CAC by segment?" and they can break it down by customer type, geography, product, and acquisition source.
This isn't magic. It's infrastructure. Attribution systems. Cost tracking. Cohort analysis. The boring plumbing that makes good decisions possible.
The Machine Mindset
Growth isn't gambling. It's engineering.
The companies that win build machines with predictable inputs and outputs. They know their numbers. They trust their numbers. They make decisions based on their numbers.
The companies that stall are still guessing. Still "feeling" their way through budget decisions. Still surprised when campaigns don't work.
Which machine are you building?
โ Back to Insights