Customer Acquisition Cost (CAC)
The total cost of acquiring a new customer, including all sales and marketing expenses, used by buyers to evaluate the efficiency of a company's growth engine and the sustainability of its unit economics.
What is Customer Acquisition Cost?
Customer Acquisition Cost (CAC) measures the total expense required to acquire a single new customer. It encompasses all sales and marketing costs -- advertising spend, sales team compensation, marketing tools, content production, and any other direct costs associated with converting prospects into paying customers.
Formula:
CAC = Total Sales and Marketing Costs / Number of New Customers Acquired
A company that spends $500,000 on sales and marketing in a quarter and acquires 200 new customers has a CAC of $2,500.
The CAC/LTV Ratio
CAC is most meaningful when paired with Customer Lifetime Value (CLV or LTV). The ratio between the two is one of the most scrutinized metrics in any acquisition:
- LTV:CAC of 3:1 or higher -- Healthy unit economics. The business earns at least three times what it spends to acquire each customer.
- LTV:CAC of 1:1 to 2:1 -- Marginal. Growth may not be self-funding.
- LTV:CAC below 1:1 -- The company loses money on every customer it acquires.
Buyers also examine CAC payback period -- how many months of revenue it takes to recover the acquisition cost. A payback period under 12 months is generally considered strong for SaaS and subscription businesses.
What Buyers Look For
During due diligence, buyers evaluate CAC from multiple angles:
- Trend over time -- Is CAC increasing or decreasing? Rising CAC suggests market saturation or declining marketing efficiency.
- By channel -- Which acquisition channels deliver the lowest CAC? Heavy dependence on a single expensive channel is a risk.
- Blended vs. fully loaded -- Does the reported CAC include all relevant costs, or are overhead and personnel costs excluded?
- Organic vs. paid -- What percentage of new customers come through organic channels (referrals, SEO, word of mouth) versus paid acquisition? Businesses with a strong organic mix have more sustainable CAC.
How CAC Affects Valuation
Low and declining CAC directly supports higher valuation multiples because it indicates:
- Efficient growth -- The business can scale without proportionally increasing spend.
- Strong brand or product-market fit -- Customers come through organic or low-cost channels.
- Higher free cash flow -- Less spending on acquisition means more cash available for distribution or reinvestment.
Conversely, high or rising CAC signals that growth is expensive and may not be sustainable, which compresses multiples.
Advice for Sellers
Track CAC by channel and cohort for at least 12 months before a sale process. Invest in reducing CAC through organic channels -- content marketing, referral programs, SEO, and partnerships. Present CAC data alongside LTV and payback period to give buyers a complete picture of your unit economics. The stronger the ratio, the stronger your negotiating position.