Customer Churn Rate Calculator
Calculate your customer churn rate and estimate how many customers you lost over a given period.
Overview
Use this Customer Churn Rate Calculator to measure how many customers you lost over a selected period based on your starting customers, ending customers, new customers, and period length. It is a simple way to track retention performance and compare trends over time.
How it works
The calculator first estimates how many of your starting customers were retained by subtracting new customers from the ending customer count. It then compares retained customers with starting customers to estimate how many were lost. Churn rate is calculated as customers lost divided by starting customers, expressed as a percentage. Retention rate is the retained share of your starting customer base.
How to use this calculator
- 1Enter the number of customers you had at the start of the period.
- 2Enter the number of customers you had at the end of the period.
- 3Add the number of new customers gained during the same period.
- 4Enter the length of the period in months.
- 5Review the churn rate, retention rate, and average monthly customer loss.
Example Calculation
Customers at Start of Period
1000
Customers at End of Period
920
New Customers Added During Period
50
Period Length
1
Customer Churn Rate
13.00%
If you started with 1,000 customers, ended with 920, and added 50 new customers during the month, the calculator estimates 130 customers lost, a churn rate of 13.00%, and a retention rate of 87.00%.
Frequently asked questions
What does this customer churn rate calculator estimate?
It estimates the percentage of customers lost during a period, along with the number of customers lost and your retention rate.
Why do I need to enter new customers?
New customers are removed from the ending total so the calculator can better estimate how many of your original customers were retained.
What is a good churn rate?
A good churn rate depends on your industry, pricing model, and customer lifecycle. Lower churn is generally better because it means you are keeping more customers.
Can I use this for monthly or yearly churn?
Yes. You can use any period as long as your starting, ending, and new customer figures all cover the same time window.
Does this calculator measure revenue churn?
No. This calculator measures customer count churn, not lost revenue. Revenue churn requires customer value or recurring revenue data.
What is the difference between churn rate and retention rate?
Churn rate shows the share of customers lost, while retention rate shows the share of starting customers that remained active.
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Assumptions and warnings
Assumptions
- New customers entered during the period are separate from customers retained from the start.
- The calculation uses customer counts rather than revenue or contract value.
- Results are estimates and depend on accurate start, end, and acquisition figures.
- The selected period is treated as a consistent measurement window.