Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate customer churn rate over a period.
5.00%
Churn rate measures the percentage of customers lost during a period -- a core retention/health metric, especially for subscription businesses.
Enter customers at the start of the period and customers lost during it. Churn rate appears instantly.
Churn Rate % = (Customers Lost / Customers at Start) × 100
Suppose a hypothetical software subscription starts the month with 500 customers and loses 25 of them during that month. Dividing 25 by 500 gives 0.05, which the tool displays as 5.00 percent. Those are the defaults loaded in the calculator. If you lost 10 customers instead, the churn rate would be 2.00 percent, a very different picture of the same business.
25 / 500 x 100 = 5.00 percent churn for the period
The result is only meaningful relative to the period you chose. A 5 percent monthly churn is not the same as 5 percent annual churn. If you want to compare monthly churn to an annual figure, be careful: simply multiplying by 12 is a rough shortcut that overstates the yearly loss, because customers lost in month two come from a base that has already shrunk. For an approximate yearly view, many analysts compound the retention instead: 95 percent monthly retention over twelve months leaves roughly 54 percent of the original group, meaning about 46 percent annual churn. Use the same period for every calculation so trends are comparable.
The tool requires a starting count above zero, since dividing by zero is undefined, and it will ask you for a valid figure otherwise. Lost customers can be zero, which returns 0.00 percent.
Churn compounds. Even a modest-looking monthly rate has a large long-term effect on customer lifespan. A common approximation is that average customer lifespan is 1 divided by the churn rate for the period, so 5 percent monthly churn implies about 20 months, while 2 percent implies about 50 months. This is a simplification that assumes churn stays constant over a customer's life, which real data often contradicts, since early-life customers usually leave at higher rates than long-tenured ones.
This calculator measures customer count churn. It does not measure revenue churn. If your lost customers were small accounts and your remaining customers upgraded, your revenue could grow even with a noticeable customer churn rate. Conversely, losing a few large accounts may hurt far more than the percentage suggests. If your pricing varies widely, track revenue-based churn in a spreadsheet alongside this count-based figure.
Small reductions in churn can be worth more than a similar percentage gain in new sales, because retained customers keep generating revenue without any additional acquisition cost.
They're related but not simply complementary once new customers are added mid-period -- see the Customer Retention Rate Calculator for the fuller formula.
Customers lost during the period divided by customers at the start of the period, times 100. Losing 20 of 400 customers is a churn rate of 5%.
No. Use only the customers you had at the beginning of the period. Customers who joined and left within the same period are not part of this simple formula.
Only when you measure them on the same starting customers. The Customer Retention Rate Calculator on this site uses the end-of-period customer count and subtracts new customers, which reaches the same figure for the same cohort.
Use the same period every time, usually a month or a year. A 5% monthly churn is not the same as a 5% annual churn; it compounds to roughly 46% of customers lost over a year.
Reference: Google Search Central