Two numbers, one division, and the answer to the most important question in a growing business: can I spend more to win customers, or am I digging my grave faster?
But this ratio has a blind spot, and it is what gets people who use it badly into trouble.
Definition
The LTV/CAC ratio divides a customer's LTV (customer lifetime value) by their CAC (customer acquisition cost). It expresses how many euros of value you get for each euro spent on acquisition.
| Ratio | Reading |
|---|---|
| Below 1 | Every new customer loses you money |
| Between 1 and 3 | Fragile: little room for fixed costs |
| Around 3 | The commonly cited healthy benchmark |
| Above 5 | Usually under-investment in acquisition |
The last row surprises people and deserves a pause. A very high ratio is not a performance, it is a sign you are leaving growth on the table: you could spend more and win more customers while staying profitable.
The blind spot: timing
The ratio says nothing about time. An LTV of €900 against a CAC of €300 gives a ratio of 3, which is good. But if those €900 arrive as thirty monthly payments of €30, you paid €300 today and will get it back in ten months.
In a month where you win thirty customers, that is €9,000 out for €900 in. This is how a company that is perfectly profitable on paper runs dry.
The cost is repaid well before departure: you can accelerate acquisition.
Both durations sit on the same scale, which is the whole point. A flattering LTV/CAC ratio says nothing if payback arrives after departure.
The demo above sets two durations against each other: the time needed to recover acquisition cost, and average customer lifetime derived from your Churn rate. When the first exceeds the second, you are paying to lose customers, whatever the headline ratio says.
The usual benchmark is payback within twelve months. For a Bootstrapping business, six months is more prudent, because nobody will plug the cash gap in the meantime.
How to move the ratio
Only two directions, and they do not cost the same effort:
- Raise LTV. Through Retention, Upsell or price. Durable effect, slow to implement.
- Lower CAC. Through Conversion rate or a better channel. Fast effect, often capped.
Starting with retention is nearly always the better choice, because every extra month of life improves both terms at once: LTV rises, and a loyal customer refers others, which lowers average CAC.
Frequently asked questions
Should LTV be calculated on margin or revenue?
On margin, always. A ratio built on revenue is systematically flattering, because it ignores the cost of serving the customer. It is the most common error with this ratio.
Does the benchmark of 3 apply to everyone?
No. It comes from funded software, where fixed costs are heavy. A solo business with €400 of monthly costs lives very well on a ratio of 2, provided payback is quick.
What if the ratio is below 1?
Stop acquisition spending immediately, before anything else. Every extra euro worsens it. The problem is then addressed through retention or price, never through more volume.
How often should I recalculate it?
Quarterly. Both terms move slowly, and reading it monthly at small volumes will have you reacting to noise.