Customer Churn Rate Formula: Exact SaaS Calculation Rules

Strict customer churn is a logo-loss rate, not a revenue-loss rate.

• CustomersAtStartOfPeriod: paying customers active at the start of the period.
• CustomersLostDuringPeriod: customers that truly churn during the period under the active churn policy.

• Do not count a failed payment as churn before grace period ends.
• Do not count a pause as churn unless policy explicitly treats pause as lost customer status.
• Reactivation next month does not erase churn recorded this month.

• Exclude trial users from the denominator unless the policy is a trial churn model.
• Exclude downgrades; they belong to contraction or revenue churn logic, not customer churn.
• Keep freemium transitions consistent: either churn from paid or move to another defined state.

• Zero starting customers: rate is undefined.
• Annual contracts: churn timing often concentrates at renewal.
• Billing recovery: involuntary churn must respect dunning completion.

Suppose a company starts the month with 800 paying customers and loses 24 after grace period logic completes.

Customer churn rate is a paying-customer logo loss rate built on a stable lost-customer policy. If grace periods are ignored or downgrades are counted as churn, the result is not strict customer churn rate.

Core metric pages:

• MRR
• MRR vs ARR
• ARR
• Net New MRR