Customer Lifetime Value and Why It Sets Your Ad Budget

How to calculate LTV, what a good ratio looks like, and how it connects to CAC and growth strategy.

February 25, 20262 min read283 words

one-line definition

LTV is a core operating metric that helps small teams make better product and growth decisions.

formula: LTV = Average revenue per customer ÷ Churn rate

tl;dr

LTV tells you how much revenue one customer generates before they churn. Compare it to CAC -- if LTV is not at least 3x CAC, your unit economics are broken.

Simple definition

LTV (Lifetime Value) is the total revenue you expect from a single customer over the entire time they stay subscribed. It connects two things: how much a customer pays you each month and how long they stick around. A high LTV means customers are either paying more, staying longer, or both.

For solo founders, LTV is the ceiling on what you can spend to acquire a customer. If your LTV is $300, spending $200 on ads per customer means you only have $100 left for everything else -- hosting, support, your salary. That math matters fast.

How to calculate it

LTV = Average revenue per customer per month / Monthly churn rate

Say your average customer pays $39/month and your monthly churn rate is 5% (0.05):

LTV = $39 / 0.05 = $780

That means a typical customer generates $780 in total revenue before leaving. If your churn drops to 3%, LTV jumps to $1,300. Small improvements in retention have an outsized effect on LTV.

Example

You run a $29/month email tool. Your churn is 8% monthly. LTV = $29 / 0.08 = $362.50. You're spending $120 on Google Ads per signup, so your LTV:CAC ratio is about 3:1 -- right at the threshold. You ship a better onboarding flow that drops churn to 6%. Now LTV = $29 / 0.06 = $483. Same acquisition cost, but each customer is worth $120 more. That extra margin lets you reinvest in content marketing or hire a part-time support person.

Related terms

  • MRR
  • CAC
  • LTV

FAQ

Why does LTV matter?+

It gives a fast signal about whether your product and distribution system is improving or regressing.

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