Customer acquisition cost calculator
Paid CAC per channel, blended CAC across the business, and what the ratio to LTV says.
Total spend ÷ total new customers. Add an organic row with zero spend to see the blended figure the business actually pays.
Runs entirely in your browser — nothing is uploaded, nothing is stored. Updated 2026-09-05.
Customer acquisition cost is what you spent to acquire a customer: acquisition spend ÷ new customers. $9,800 producing 140 new customers is a CAC of $70.
Two versions of that number circulate and they answer different questions. Paid CAC divides one channel's spend by the customers that channel produced, and it tells you whether that channel is worth funding. Blended CAC divides all acquisition spend by all new customers, organic ones included, and it tells you what the business actually pays to grow. Reporting the blended figure as if it were the paid one is the most common way CAC gets flattered. Both are below.
CAC = acquisition spend ÷ new customers acquired
What belongs in the numerator
Ad spend alone understates CAC, sometimes badly. A defensible acquisition cost includes the media, the salaries of the people running it, agency retainers and the tooling — everything you would stop paying if you stopped acquiring.
What does not belong: retention marketing, customer success, and anything spent on people who are already customers. Those costs are real, but they belong to a different question. Pick one boundary, write it down, and keep it stable — a CAC that improves because someone quietly moved a salary line is not an improvement.
CAC without a time boundary is not a number
Spend lands immediately; customers arrive over weeks. Divide this month's spend by this month's new customers during a period when spend is growing and you overstate CAC; do it while spend is shrinking and you understate it.
Either use a cohort — spend in a window against customers attributable to that window — or use a period long enough that the lag washes out. Most subscription businesses find that quarterly figures are stable where monthly ones swing by thirty per cent on nothing.
The ratio matters more than the level
A CAC of $700 is fine against a $6,000 lifetime value and fatal against a $900 one. The convention in subscription businesses is an LTV to CAC ratio of about 3:1, with the caveat that it should be computed on gross-margin LTV rather than lifetime revenue — using revenue inflates the ratio by your entire cost of goods.
The second number that matters is payback period: how many months of gross profit it takes to earn the acquisition cost back. A healthy ratio with a two-year payback is still a cash-flow problem.
Computing this from your own accounts
Every calculator on this page takes numbers you typed. The version that keeps working is the one that reads them from the accounts themselves — which is what TableBI is: connect Google Ads, Meta Ads, GA4 or Search Console once, and cpa() becomes a macro you can query from your terminal.
# connect once, then the metric is a standing query tablebi connect google_ads tablebi connect meta_ads # beta: your own or test ad accounts tablebi ask "WITH w AS (SELECT MAX(date) AS anchor FROM metrics) SELECT platform, cpa(SUM(cost), SUM(conversions)) AS cpa FROM metrics, w WHERE date > w.anchor - 30 GROUP BY platform ORDER BY cpa DESC" # pin the answer to a URL that refreshes itself tablebi pin --title "customer acquisition cost calculator by channel" → https://you.tablebi.com/d/dsh_…
The pinned answer is a live URL that refreshes on its own — here is one running now. No hosted model does the reasoning; your own Claude Code or Codex drives the CLI, which is why there is no inference bill attached to it.
Questions people ask about customer acquisition cost calculators
How do I calculate customer acquisition cost?
Divide total acquisition spend over a period by the number of new customers acquired in that period. $9,800 producing 140 new customers gives a CAC of $70.
What is the difference between CAC and CPA?
CPA is cost per acquisition of any defined conversion — a lead, a signup, a trial. CAC is specifically the cost of acquiring a paying customer. In a business where every conversion is a purchase the two coincide; where there is a funnel between signup and payment they differ, sometimes by a large multiple.
What is the difference between blended CAC and paid CAC?
Paid CAC divides one channel spend by the customers that channel produced. Blended CAC divides all acquisition spend by all new customers, including organic ones who cost nothing. Blended CAC is always the lower number, and quoting it as a paid channel result is the most common way the metric gets flattered.
What is a good LTV to CAC ratio?
Around 3:1 is the usual benchmark in subscription businesses, computed on gross-margin lifetime value rather than lifetime revenue. Below 1:1 you lose money on every customer; far above 3:1 usually means you are underspending on growth rather than running an unusually good business.
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