# Calculating subscriber churn rate in Billing

## Subscriber Churn Rate
The churn rate is measured by the sum of churned subscribers in the past 30 days divided by the number of active subscribers as of 30 days ago, plus any new subscribers in those 30 days.
## What Qualifies as Churn
Subscriber churn occurs when a subscriber goes from non-zero [Monthly Recurring Revenue​ (MRR)](/questions/understanding-monthly-recurring-revenue-%28mrr%29) to zero MRR. This means that if a customer has two paid subscriptions and cancels one of them, this will not count as subscriber churn, but if the customer cancels both subscriptions, this will count as a subscriber churn.
A customer that previously ended all active subscriptions and has now restarted will be counted as a reactivated subscriber, and if that customer ends all active subscriptions again, it will be counted as a second churn.
If a new subscriber both activates and churns during that 30 day period, we will include that churned subscriber in both the numerator and denominator.
## Trials and Canceled Subscriptions
If a subscription transitions from trialing to active, the subscription will then count towards your MRR even if the first invoice is unpaid.
Eventually, if the subscription is canceled or marked unpaid due to the unpaid invoice, the subscription will no longer count towards your MRR and will count toward your churn.
## Churned Revenue
The churned revenue for a given period is a sum of lost Monthly Recurring Revenue ("MRR”) from churned subscribers.