Churn Rate Calculator
Calculate customer churn rate and retention rate from customers lost and starting customers, with annualised churn for subscriptions.
Last reviewed by the Radiatus Cloud team
Calculate customer churn and retention rate for a subscription or SaaS business.
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Calculate churn and retention rate
Churn rate is the percentage of customers who stop using a product or cancel a subscription during a period. It is calculated by dividing the number of customers lost by the number of customers at the start of the period. A business that begins a month with one thousand customers and loses fifty has a monthly churn rate of five percent, and a retention rate of ninety-five percent. This calculator also annualises a monthly churn figure and estimates the average customer lifespan, which is the reciprocal of the churn rate.
Retention and churn always sum to one hundred percent, so improving one directly improves the other.
Why churn is critical
For subscription and software businesses, churn is one of the most important metrics because it determines how fast customers must be replaced just to stand still. Even a seemingly small monthly churn compounds dramatically over a year: five percent monthly churn means losing nearly half of customers annually. Reducing churn is often more valuable than acquiring new customers, since retained customers cost nothing extra to win and tend to spend more over time.
The average customer lifespan derived from churn feeds directly into customer lifetime value calculations. Track churn by cohort and reason to understand where and why customers leave. All calculation happens locally in your browser.
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Frequently Asked Questions
What is the churn rate formula?
Churn rate equals customers lost during a period divided by customers at the start of that period, expressed as a percentage.
How does churn relate to retention?
They are complements that sum to one hundred percent. A five percent churn rate means a ninety-five percent retention rate.
Why annualise monthly churn?
Monthly churn compounds, so annualising shows the true yearly impact. Five percent monthly churn loses nearly half of customers over a year.
How does churn affect lifetime value?
The average customer lifespan is the reciprocal of the churn rate, and that lifespan is a key input to customer lifetime value.
Why focus on reducing churn?
Retained customers cost nothing extra to acquire and tend to spend more over time, so cutting churn often boosts profit more than chasing new customers.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Enter customers at the start of the period and customers lost.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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