Unsubscribe rate is a term which is usually defined in the context of internet marketing and specifically email marketing. It is as the name suggests a measure of the number of people who actually click on the unsubscribe button and opt-out of your newsletter or receiving daily updates about your products and services. These users no longer have access to your email announcements and can thus no longer contribute towards your website’s engagement or SEO. It is calculated on the basis of per email campaign sent.