What Is Customer Acquisition Cost?
CAC is the total cost to acquire one new customer including marketing and sales. The LTV:CAC ratio determines whether your business model is viable.
Definition
Customer Acquisition Cost (CAC) is the total cost of sales and marketing divided by the number of new customers acquired in a period. If you spent $100,000 on sales and marketing in Q1 and acquired 50 customers, your CAC = $100,000 / 50 = $2,000.
CAC must be evaluated relative to Customer Lifetime Value (LTV). The LTV:CAC ratio is the fundamental unit economics test for a SaaS business. An LTV:CAC ratio of 3:1 or better is the baseline for a viable business; 5:1+ indicates a capital-efficient growth engine.
CAC Payback Period shows how many months of revenue are needed to recover the acquisition cost. A 12-month CAC payback is solid for SMB SaaS; 18-24 months is acceptable for enterprise SaaS with long-term contracts. Payback over 24 months is capital-intensive and risky.
Real-World Example
A SaaS company spends $60K on marketing and $40K on sales in a month, acquiring 20 new customers. CAC = $100K / 20 = $5,000. If customers pay $500/month (with 80% gross margin) and stay an average of 24 months, LTV = $500 × 0.80 × 24 = $9,600. LTV:CAC = $9,600/$5,000 = 1.9x — below the 3x threshold, meaning the business is burning money to grow.
Why It Matters
CAC is the investment side of the customer equation — without understanding your cost to acquire customers, you can't know whether growth is profitable or just expensive. Scaling with a bad LTV:CAC ratio accelerates losses.
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Frequently Asked Questions
What is a good LTV:CAC ratio?
3:1 is the minimum acceptable ratio — you earn $3 for every $1 spent acquiring a customer. 5:1 is strong. Above 5:1 may indicate under-investment in growth (you're leaving money on the table by not acquiring more customers). VCs typically want to see 3:1+ before funding growth.
How do I reduce CAC?
Improve conversion rates at each stage of the funnel (lower cost per lead → lead → trial → customer). Build organic channels (SEO, content, word-of-mouth) that have near-zero marginal CAC. Build self-serve products where customers can sign up without a sales rep. Improve targeting to focus spend on highest-converting segments.
Should sales salaries be included in CAC?
Yes — fully-loaded CAC includes all sales team salaries, commissions, marketing spend, tools, and overhead attributable to customer acquisition. Some companies use 'blended CAC' (all S&M costs) or 'paid CAC' (only paid media). Being consistent in your methodology matters for tracking trends.
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