CAC is what you spend to acquire one customer; LTV is the total gross profit that customer generates over their relationship with you. Both are needed to judge unit economics. A $500 CAC is fine if LTV is $1,500 (3:1), and disastrous if LTV is $400 (you lose money on every sale). Always evaluate them together, never CAC in isolation.

Payback period is the number of months it takes monthly gross profit per customer to recover CAC. With a $500 CAC and $50 in monthly gross profit per customer, payback is 10 months. Shorter payback frees cash for reinvestment; longer payback means you fund growth out of working capital or external capital. SaaS investors typically want under 12–18 months.

Include fully loaded sales and marketing costs for the period: paid media, content and SEO production, marketing and sales salaries plus benefits, agency fees, martech and sales tools, events, and sales commissions tied to new business. Exclude customer success, support, and renewal expense, which belong to retention economics, not acquisition.

The widely cited benchmark is 3:1 or higher. Below 1:1 the business loses money on every customer; 1:1–3:1 is marginal and leaves little room to invest in growth; 3:1–5:1 is healthy; above 5:1 may signal underinvestment in growth. Compare to your industry: financial services often targets 5:1+, while volume-driven consumer apps can run leaner.

Paid acquisition channels have become more crowded and expensive, iOS privacy changes (ATT) reduced ad targeting efficiency, and Google and Meta auction prices have risen year over year. Multiple SaaS benchmark reports show CAC up materially since 2013. The response is to diversify into owned channels like content, community, and referrals, and to lean harder on retention to protect LTV:CAC.

Rough industry ranges: B2B SaaS $200–$1,000+, financial services $100–$500, marketplaces $50–$200, ecommerce $30–$200, and mobile consumer apps $5–$50. Higher CAC is acceptable when LTV is correspondingly higher, which is why enterprise software tolerates four-figure CAC while a consumer game cannot.

Track both. Blended CAC divides total sales and marketing spend by all new customers, including organic ones, and reflects the true cost of running the growth engine. Paid CAC divides paid spend by customers attributed to paid channels and is useful for media budgeting. Investors typically focus on blended CAC because it cannot be gamed by reclassifying channels.