Customer Retention Rate Calculator

Work out your customer retention rate for any period, using the standard start, end and new-customer formula.

Your numbers

Customers at the start of the period

Customers at the end of the period

New customers acquired during the period

Your result · updates as you type

Customer retention rate

87%

Of the 1,000 customers you started with, about 870 (87%) were still buying by the end of the period.

Retained customers: 870
Customer churn rate: 13%
Net customer growth: +80

This is the standard cohort retention formula. It treats anyone who didn't buy again as churned, even if they're still a happy customer who simply hasn't needed to reorder yet.

Breakdown

Customers at start (S): 1,000
Customers at end (E): 1,080
New customers acquired (N): 210
Retained (E − N): 870
Retention rate ((E − N) ÷ S): 87%

The standard retention formula

This is the standard cohort retention formula used across subscription and ecommerce analytics: it isolates how many of the customers you started with are still buying, separate from new customers you brought in during the same period.

Customer retention rate = (customers at end − new customers acquired) ÷ customers at start

Example: the default numbers

Customers at start (S): 1,000
Customers at end (E): 1,080
New customers acquired (N): 210

Retained customers are 1,080 − 210 = 870. Retention rate is 870 ÷ 1,000 = 87%. Customer churn rate is the other 13%.

Picking a period

Match the period to your natural reorder cycle. A monthly retention rate makes little sense for a product people buy twice a year.
"Still buying" is a strict test. A customer who's still a fan but hasn't needed to reorder yet counts as churned by this formula. That's intentional, but worth remembering when the number looks worse than expected.
For a subscription business specifically, the subscription churn calculator separates customer churn from revenue churn, which often move differently.

Questions people ask

What is customer retention rate?

The share of customers you had at the start of a period who were still buying by the end, excluding anyone who only became a customer during that period.

How is retention rate different from churn rate?

They're complements: retention rate + churn rate = 100%. A 87% retention rate is the same as a 13% churn rate over the same period.

Why does the formula subtract new customers?

Without subtracting them, a store that lost every existing customer but gained enough new ones would still show growth in the end-of-period count, hiding the churn problem entirely.

What's a good retention rate for an online store?

It varies too much by category to give one number. Track your own trend, and compare it against your customer acquisition cost: a low retention rate makes every new customer more expensive to have won.

Last reviewed 30 September 2026.