Customer Acquisition Cost (CAC)

Customer Acquisition Cost (CAC) is the total cost of converting a prospect into a paying customer. The formula is: CAC = Total Acquisition Costs / Number of New Customers Acquired. For e-commerce brands, this includes paid advertising (Meta, Google, TikTok), creative production, agency fees, influencer costs, affiliate commissions, promotional discounts offered to first-time buyers, and the allocated cost of team members working on acquisition.

The most common CAC mistake is including only ad spend. A brand spending $50,000/month on Meta Ads with a $5,000/month agency fee, $3,000 in creative production, and $10,000 in first-purchase discounts that acquires 1,000 customers has a true CAC of $68, not $50. Under-counting CAC leads to over-estimating profitability and scaling unprofitable acquisition channels.

CAC should always be evaluated relative to customer lifetime value (LTV). The standard benchmark is a minimum 3:1 LTV:CAC ratio — every $1 spent on acquisition should generate $3 in lifetime value. Below 2:1, the business is likely unprofitable after fixed costs. Above 5:1, the brand may be under-investing in growth.

Blended CAC (total spend / total new customers) is useful as an overview but hides channel-level economics. Calculate CAC by channel (Meta, Google, TikTok, organic, referral) and by campaign to understand which acquisition paths are truly profitable. Some channels with high CAC may bring customers with significantly higher LTV — making them more valuable despite the higher upfront cost.

Payback period — the time it takes for a customer's cumulative contribution margin to exceed their CAC — is often more actionable than the LTV:CAC ratio alone. A 3:1 ratio with a 3-month payback is far healthier than 3:1 with a 12-month payback, because shorter payback means faster cash recycling into new acquisition.