Customer Acquisition Cost (CAC)

Customer acquisition cost (CAC) is the single most important metric for understanding whether your growth is actually profitable. Growing fast while ignoring CAC creates a trap: ad spend scales up while margins silently erode. The LTV/CAC ratio tells you what CAC alone cannot — is the lifetime value of a customer actually paying back what it costs to acquire them? ProfitWell research shows that average CAC for B2B SaaS companies rose 60% between 2019 and 2023, making LTV/CAC tracking essential rather than optional (ProfitWell, 2023). The benchmark: an LTV/CAC ratio of 3x or above is considered healthy; below 1.5x means the business is overspending relative to customer value and the model should be re-examined. Bain & Company's research demonstrates that retaining an existing customer costs 5–7× less than acquiring a new one — meaning that improving retention and LTV often produces faster ratio improvements than cutting acquisition spend (Bain & Company, Customer Retention Research).

1. 1

   Calculate CAC by channel (Google Ads, Meta, organic, referral) — see the true efficiency of each channel separately

2. 2

   Design upsell, cross-sell and loyalty programmes to increase LTV — doubling LTV automatically improves the ratio

3. 3

   If LTV/CAC < 1.5x, prioritise a churn reduction plan; retaining an existing customer costs 5–7x less than acquiring a new one

4. 4

   Track CAC quarterly rather than monthly — short-term fluctuations can be misleading