Ghost(Pro) plans are determined using two metrics: staff users and members. Find all of the current plans on the pricing page.
Staff Users
Staff users are the total number of users invited to your team in Ghost Admin. Note that users with the role of "Contributor" or have a status of "Suspended" do not count towards plan limits. Pending invites to the publication do count towards plan limits.
If you exceed the number of total staff users for your plan, we will inform you by email to let you know that it's time to upgrade, or change the role of users from the Staff section within Ghost admin.
Members
Members are any visitors who have signed up to access the content on your site using the Members features in Ghost. This includes members who have free access to your content, as well as those who have an active subscription via the Stripe integration.
Each individual member account and its associated email address is counted as 1 member.