Definition
CAC (Customer Acquisition Cost) is the cost to acquire a new paying customer. CAC is most useful when paired with payback or LTV and when the definition stays consistent over time.
Formula
CAC = acquisition spend / new customers acquired
Example
If you spent $120,000 on acquisition in a month and acquired 80 new paying customers, CAC = $120,000 / 80 = $1,500.
Common mistakes
- Using leads or trials as 'customers'.
- Mixing paid-only CAC and fully-loaded CAC without labeling.
- Ignoring churn and gross margin when judging CAC.
Measured as
CAC = acquisition spend / new customers acquired
Misused when
- Using leads or trials as 'customers'.
- Mixing paid-only CAC and fully-loaded CAC without labeling.
- Ignoring churn and gross margin when judging CAC.
Operator takeaway
- Keep CAC Meaning: Formula, Example, and What Counts in CAC consistent by cohort, segment, and period before you use it as a decision signal in planning or reporting.
- Interpret the metric alongside retention, margin, or payback so one ratio does not hide the real operating trade-off.
Next decision
- Quantify the impact with CAC Calculator if you need to turn the definition into an operating assumption.
- Read CAC guide: formula, payback, fully-loaded CAC, and LTV:CAC if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.
Where to use this on MetricKit
Calculators
- CAC Calculator: Calculate Customer Acquisition Cost (CAC) from total acquisition spend and new customers.
- Blended CAC Calculator: Compare paid-only CAC vs fully-loaded (blended) CAC, and estimate payback at a target margin.
- CAC Payback Period Calculator: Estimate how many months it takes to recover CAC (months to recover CAC) using gross profit.
- Fully-loaded CAC Calculator: Calculate fully-loaded CAC by including paid spend plus sales & marketing costs (salaries, tools, and other acquisition costs).
- LTV:CAC Calculator: Compute LTV:CAC ratio and CAC payback using ARPA, gross margin, churn, and CAC.
Guides
- CAC guide: formula, payback, fully-loaded CAC, and LTV:CAC: A practical CAC guide covering the formula, what to include, paid vs fully-loaded CAC, payback, LTV:CAC, and how to judge acquisition quality without fooling yourself.
- CAC vs CPA: definitions, formulas, and when to use each: CAC vs CPA explained: what each metric measures, how to calculate them, and how to translate CPA into CAC for planning.
- Blended CAC vs paid CAC: when each is the right metric: CAC depends on what you include. Learn paid-only CAC vs fully-loaded blended CAC, how to avoid mismatches, and how to connect CAC to payback.
- CAC Payback Period (Months to Recover CAC): definition, formula, benchmarks: Learn how to calculate CAC payback (months to recover CAC) using gross profit, plus benchmarks and levers to improve it.
- Fully-loaded CAC: formula, what to include, and how to use it: Learn how to calculate fully-loaded CAC, which sales and marketing costs belong in it, how it differs from paid CAC, and how to pair it with payback for planning.