Churn Rate Calculator Formula

Understand the math behind the churn rate calculator. Each variable explained with a worked example.

Use the Churn Rate Calculator

Formulas Used

Churn Rate

churn_rate = customers_start > 0 ? (customers_lost / customers_start) * 100 : 0

Retention Rate

retention_rate = customers_start > 0 ? ((customers_start - customers_lost) / customers_start) * 100 : 0

Customers Remaining

customers_remaining = customers_start - customers_lost

Variables

VariableDescriptionDefault
customers_startCustomers at Start of Period1000
customers_lostCustomers Lost During Period50

How It Works

How to Calculate Churn Rate

Formula

Churn Rate = (Customers Lost / Customers at Start) x 100 Retention Rate = 100 - Churn Rate

Churn rate is the inverse of retention. It tells you what fraction of your customer base walks away during a given period (usually monthly or annually). Even small differences in churn compound dramatically: a company with 3% monthly churn loses roughly 31% of customers yearly, while 5% monthly churn means losing over 46% annually.

Worked Example

A subscription business starts the month with 1,000 customers and loses 50.

customers_start = 1000customers_lost = 50
  1. 01Churn Rate = (50 / 1,000) x 100 = 5%
  2. 02Retention Rate = 100 - 5 = 95%
  3. 03Customers Remaining = 1,000 - 50 = 950

Ready to run the numbers?

Open Churn Rate Calculator