Business & SaaS

LTV:CAC Ratio Calculator

What this does

Check whether customer lifetime value comfortably exceeds acquisition cost, benchmarked against the classic 3:1 rule of thumb.

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Calculator inputs

Using the ltv:cac ratio calculator

  1. 01

    Enter LTV

    Use the gross-profit version from the CLV calculator, not revenue.

  2. 02

    Enter CAC

    Fully loaded acquisition cost for the same period or channel.

  3. 03

    Read the verdict

    The interpretation row compares your ratio against the 3:1 benchmark and its upper bound.

Reading both directions of the ratio

Below 3:1, every growth dollar buys relationships that barely repay themselves; fix retention, pricing or targeting before scaling. Above roughly 5:1, the opposite problem looms: markets willing to pay far more than you spend suggest competitors will happily spend more to serve them. Healthy growth lives in the middle, then pushes outward deliberately.

Companion metrics

  • CAC payback months; how quickly each customer repays their cost.
  • Gross margin; inflates LTV and therefore the ratio; keep definitions consistent.
  • Retention/churn; the single biggest driver of LTV over time.

The math behind this calculator

Ratio = LTV / CAC (benchmark ≥ 3:1)

The ratio divides the gross profit an average customer generates by what it cost to acquire them. Below 1:1 you lose money on every sale immediately. The widely cited SaaS benchmark of 3:1 leaves room for overhead, churn surprises and capital cost, while ratios far above 5:1 often signal a company too conservative with growth spending.

Assumptions & limitations

  • LTV is measured in gross profit, not revenue.
  • CAC is fully loaded (salaries, tools, agencies) and matched to the same cohort.
  • Static snapshot; cohorts and ratios shift as pricing and channels mature.

Worked example

Customers worth $3,600 in lifetime gross profit who cost $1,200 to acquire yield a 3:1 ratio; right at the healthy benchmark.

Frequently asked questions

Is 3:1 a hard rule?
It is a heuristic, strongest for subscription businesses. Enterprise sales cycles tolerate longer paybacks; transactional e-commerce often needs higher ratios because repeat behavior is less certain.
My ratio is 8:1; should I celebrate?
Partly. It means excellent unit economics but possibly underinvestment: if demand holds, spending more on acquisition at even 4:1 returns compounds faster.
Can I compute this per channel?
Yes and you should; divide each channel’s attributed LTV by its fully loaded CAC. Blended ratios hide that one channel subsidizes another’s losses.

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