The CAC ratio is calculated by dividing the total cost of acquiring new customers (CAC) by the average revenue per customer (ARPC). This ratio is a helpful way to measure how efficiently a company is spending its resources to acquire new customers and can be used to compare different companies or different periods of time for the same company. To calculate your company's CAC ratio, simply divide the total cost of acquiring new customers (CAC) by the average revenue per customer (ARPC). For example, if a company spends $100 to acquire each new customer, and the average revenue per customer is $200, then the company's CAC ratio would be 0.5.