Customer attrition is simply the number of lost customers by a business. Most customers of a business will not remain active indefinitely regardless of whether they’re a one-time buyer or a loyal customer. However, it is important to understand reasons for losing customers and attempt to combat these.
Customer attrition is generally expressed as a percentage on a monthly or annual basis. To calculate your customer attrition rate simply divide the number of customers lost by the end of the period by the total number of customers at the beginning of the period.