An active user is any user that signs in at least once during your monthly (30 day) billing cycle. Once a user has logged in, they will not be counted again as an Active User during your 30-day billing cycle, regardless of how many times they log in.
When the next month of your billing cycle begins, the number of Active Users is reset.
Active User Limits (before overage charges begin):
Starter: 100 Active Users/Month
Advanced: 250 Active Users/Month
Premium: 500 Active Users/Month
Enterprise: 1000+ Active Users/Month