Calculate your Customer Acquisition Cost, Lifetime Value, LTV:CAC ratio, and payback period. Understand your SaaS unit economics in seconds.
Customer Acquisition Cost (CAC) and Customer Lifetime Value (LTV) are the two most important unit economics metrics for any SaaS business. Together, they tell you whether your business model is sustainable and how efficiently you are growing.
CAC measures how much you spend to acquire each new customer. This includes all marketing expenses (paid ads, content marketing, SEO tools, events) and sales costs (salaries, commissions, CRM tools). To calculate CAC, simply divide your total marketing and sales spend by the number of new customers acquired in the same period.
LTV estimates the total revenue you can expect from a single customer over the entire relationship. The simplest formula uses three inputs: your average revenue per user (ARPU), gross margin percentage, and monthly churn rate. Higher ARPU and lower churn both increase LTV significantly.
The LTV:CAC ratio is the gold standard metric for evaluating unit economics. It tells you how much value you generate for every dollar spent on acquisition. A ratio below 1:1 means you are losing money on every customer. Between 1:1 and 3:1 indicates your economics need improvement. The widely accepted SaaS benchmark is 3:1 or higher, meaning you earn three dollars in lifetime value for every dollar spent acquiring a customer.
The payback period complements the LTV:CAC ratio by showing how quickly you recover acquisition costs. Most healthy SaaS businesses recover CAC within 12 months. A shorter payback period means faster cash flow recovery and less capital required for growth. If your payback period exceeds 18 months, you may need to improve pricing, reduce churn, or find more efficient acquisition channels.
If you spend $10,000 on marketing in a month and acquire 50 new customers, your CAC is $200.
If your ARPU is $49/month, gross margin is 80%, and monthly churn is 5%, your LTV is ($49 × 0.80) / 0.05 = $784.
Based on data from hundreds of SaaS companies, here are the key benchmarks for healthy unit economics:
Companies with an LTV:CAC ratio above 3x and a payback period under 12 months are generally considered investment-ready by VCs.See real unit economics from 800+ startups →
CAC is the total cost of acquiring a new customer, including all marketing and sales expenses divided by the number of new customers acquired in that period. It helps you understand how efficiently you are converting spend into paying customers.
LTV is the total revenue a business can expect from a single customer over the entire duration of their relationship. It factors in average revenue per user (ARPU), gross margin, and churn rate to estimate the long-term value of each customer.
A healthy SaaS business typically has an LTV:CAC ratio of 3:1 or higher. Below 1:1 means you are losing money on each customer. Between 1:1 and 3:1 needs improvement. Above 5:1 may indicate under-investment in growth and an opportunity to scale faster.
Payback period is calculated by dividing CAC by the monthly gross profit per customer (ARPU multiplied by gross margin). It tells you how many months it takes to recoup the cost of acquiring a customer. Under 12 months is considered healthy for SaaS.
You should recalculate CAC and LTV at least monthly. Track trends over time rather than focusing on a single snapshot. Seasonal variations in marketing spend or churn can significantly affect these metrics, so quarterly averages are also useful.
Include all marketing spend (ads, content, SEO, events), sales team salaries and commissions, marketing tools and software, and any other costs directly related to acquiring new customers. Do not include product development or general overhead.