LTV Meaning and Formula | Check the LTV:CAC 3x Rule

In one line

LTV (Lifetime Value) is the total revenue a single customer generates before churning. The simplest version estimates it as average revenue (ARPU) × average lifespan.

Why it's always an estimate

LTV depends on the future, so it can't be measured with certainty — only estimated. Better retention means customers stick around longer, which raises LTV. Early cohorts are especially prone to over- or under-estimation, since there isn't much data yet.

Run the numbers

At $5 monthly ARPU and a 12-month average lifespan, LTV is $60. Against a $20 CAC, that is an LTV:CAC of 3:1.

But that $60 does not arrive at once. At $5 a month, recovering the $20 CAC takes four months. A ratio that looks healthy still means four months before that customer has paid back what you spent to acquire them — and you have to fund the next four months of spend in the meantime. That is why the ratio and the payback period have to be read together.

Where it's used

LTV pairs with CAC in the LTV:CAC ratio to judge whether it's worth continuing to spend on a channel. 3:1 is a commonly cited healthy benchmark, but the right threshold varies a lot by industry and margin structure.

Run the numbers

LTV means little on its own — it has to be read against CAC. The LTV:CAC calculator shows your ratio against the commonly used 3x line, plus the payback period.

Go deeper

How to calculate LTV:CAC and interpret it is covered in LTV:CAC Ratio.

Frequently asked questions

How do you calculate LTV?

The simplest form multiplies average revenue (ARPU) by average lifespan. At $5 monthly ARPU and a 12-month average lifespan, LTV is $60. Lifespan itself is estimated from the retention curve, which is why the result is always an estimate rather than a measurement.

Why is LTV:CAC of 3:1 used as the benchmark?

An LTV of $60 against a CAC of $20 gives 3:1, and that line is widely cited as healthy. It is a reference rather than a rule — thin margins or slow payback can make 3:1 insufficient, so the threshold has to be set against your own margin structure.

If LTV exceeds CAC, why is cash still tight?

Because LTV arrives over time. A $60 LTV spread across 12 months is $5 a month, so recovering a $20 CAC takes four months. That recovery window is the payback period, and a long one ties up cash no matter how healthy the ratio looks.