A measurement that allows you to assess the cost of scaling up your business.
It can be calculated by dividing the time and money spent on customer acquisition for a specific period of time by the number of new customers gained.
(Money + Time Spent)/Number of New Customers
For example, if you spend $500,000 on Sales and Marketing in a given month and added 50 customers that same month, then your CAC was $10,000 that month.