📈 Metrics

Churn

The share of customers who leave in a period.

Formula

Churn % = Customers lost ÷ Customers at start of period

Churn is the opposite of retention. 5% monthly churn means you lose 1 in 20 customers every month.

High churn forces you to keep buying new customers just to stand still.

🧮 Example

Start the month with 1,000 subscribers, lose 40 → churn = 4%.

🎯 Interview tip

Ask ‘why do they leave?’ — price, product, competitor or onboarding? Each needs a different fix.

Used in

Learn next

Lifetime value (LTV)

The total profit a customer brings before they leave.

Retention & cohorts

Track groups who joined at the same time to see who sticks around.

ARPU

Average revenue per user.

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