LTV:CAC Ratio
The ratio of Customer Lifetime Value to Customer Acquisition Cost. A healthy SaaS business targets a 3:1 ratio or higher. Affiliate marketing typically improves this ratio because commissions are performance-based.
The Critical LTV:CAC Ratio
The LTV:CAC ratio compares customer lifetime value (total profit from customer over relationship) to customer acquisition cost (all sales and marketing expenses to acquire customer). This ratio directly indicates marketing efficiency and business sustainability. A 3:1 LTV:CAC ratio means each acquired customer generates three dollars of profit for every dollar spent acquiring them. This ratio predicts whether a SaaS company can scale profitably. Higher ratios indicate strong unit economics; lower ratios suggest unsustainable customer acquisition.
Calculating LTV and CAC
LTV = ARPU × Gross Margin × Customer Lifespan. Example: $100 monthly ARPU × 80% gross margin × 36 months average customer lifetime = $2,880 LTV. CAC = Total Sales + Marketing Costs / Number of New Customers. Example: $10,000 monthly marketing spend + $15,000 sales salary allocated to new customer acquisition / 20 new customers = $1,250 CAC per customer. LTV:CAC = $2,880 / $1,250 = 2.3:1. Benchmark metrics: healthy SaaS maintains 3:1 to 5:1 LTV:CAC ratio. Below 3:1 indicates customer acquisition is expensive relative to customer value. Above 10:1 suggests potential underinvestment in growth.
Improving Ratio Through Affiliate Programs
Affiliates typically reduce CAC relative to paid advertising because commissions are performance-based. Affiliate-sourced customers cost 30-50% less to acquire than paid advertising cohorts. Improve LTV:CAC by recruiting affiliates targeting high-LTV customer segments. Measure LTV by acquisition source—affiliate-sourced customers may have higher LTV due to better product fit. Recruit affiliates whose audiences have demonstrated high customer quality. Focus affiliate recruitment on partners with highly engaged audiences—quality followers drive higher conversion and lower churn. Monitor LTV:CAC ratio by acquisition channel quarterly. If affiliate channel achieves 4:1 while paid advertising achieves 2:1, allocate more budget to affiliate growth. Calculate cohort payback periods: how long before CAC investment returns revenue? Affiliate cohorts with sub-12-month payback periods are highly valuable for reinvestment.
