Customer Churn: Definition, Formula and How to Track It
By Alva Chew · Updated
Definition Customer churn is the percentage of customers you had at the start of a period who have stopped buying by the end of it. The formula is customers lost divided by customers at the start, times 100. A shop that starts the quarter with 400 customers and loses 120 has a 30% churn rate.
What is customer churn?
Customer churn is the loss of customers over a set period. It is usually quoted per month, quarter or year, as a percentage of the customers you started with. The term comes from subscription businesses, where a customer churns on the day they cancel.
A café, restaurant or shop has no cancellation date. A regular simply stops coming, and nothing in your till tells you when. That makes churn a number you have to define yourself before you can measure it.
How do you calculate churn rate?
Formula: customers lost during the period ÷ customers at the start of the period × 100.
| Item | Illustrative number |
|---|---|
| Active customers at the start of the quarter | 400 |
| Of those, still buying at the end | 280 |
| Customers lost | 400 - 280 = 120 |
| Churn rate | 120 ÷ 400 × 100 = 30% |
| Retention rate | 100% - 30% = 70% |
These numbers are made up to show the arithmetic. Count only the customers who were active at the start. New customers gained during the quarter do not change the churn rate, because they were not in the starting group. The same figure seen from the other side is the customer retention rate.
When has a customer churned if they never cancel?
You need a rule for “lapsed”. Two rules fit most small businesses:
- No purchase in 90 days. Suits cafés and lunch spots where regulars come every week.
- No purchase in 180 days. Suits bakeries, restaurants and shops where a good customer may visit monthly or less.
Pick the window that matches how often your regulars really come, then keep it fixed. A customer who passes the window is counted as churned, even though they may return later. If they do, count them as won back and track that separately.
Why does churn matter to a small shop?
Replacing a lost customer costs money, and the customer acquisition cost is what you pay to replace each customer you lose. Bain & Company states the stakes in one sentence, quoted below.
| Claim | Who says it | Scope |
|---|---|---|
| “By increasing retention by as little as 5 per cent, profits can be boosted by as much as 95 per cent” | Bain & Company, 2006, which calls it the “Bain & Company theory” | A consultancy’s own theory, no method or sample given on the page |
Source: Bain & Company, “Retaining customers is the real challenge”, 20 January 2006, opened 5 November 2026.
Treat that as an upper bound from a theory, not a forecast for your shop. The page gives no method, so it says nothing about how much profit a café would gain. Your own numbers will tell you more. If you lose 30 customers a month and each spends US$8 a visit twice a month, that is about US$480 a month of repeat sales that has to be replaced before you grow.
What is a good churn rate?
There is no single good number, and a benchmark from a subscription business says little about a shop. Measure your own rate for three or four periods first. Then judge changes against that baseline. Churn from 30% down to 25% after a change you made is more useful than any figure from another industry.
How can a loyalty program help you track churn?
A till records sales, not people. If customers pay with cash or a different card each time, you cannot tell who has stopped coming. A loyalty program gives each member an account, so each visit is tied to a person and you can list who bought in each window.
The figure covers members only, so it describes your most engaged customers and not everyone who walks in. Say so when you report it.
A points-based loyalty program also gives members a balance that grows with each purchase, which is a reason to come back. To test whether it lowers churn, compare the churn rate of members who joined before and after launch. Then check whether members with a balance lapse less often than members with none. For customers who have already lapsed, see how to win back lapsed customers. Add the repeat purchase rate alongside, since it shows how many customers buy more than once.
Tracking churn with Gimify
Gimify keeps one points balance per member across every outlet, so a member who moves between branches stays one person in your records. Members join by scanning a QR code and the card lives in Google Wallet, with no app download. The free plan covers one outlet with unlimited members.
Questions owners ask
What is customer churn?
Customer churn is the loss of customers over a period. It is usually quoted as a percentage: customers who stopped buying divided by the customers you had at the start.
How do I calculate churn rate for a café or shop?
Count the customers who were active at the start of the period, count how many of them did not buy again in a window you set, divide the second number by the first and multiply by 100. 120 lost out of 400 is 30%.
When has a customer churned if they never cancel?
A shop has no cancellation, so you choose a rule. A common one is no purchase in the last 90 days for a café, or 180 days for a bakery or restaurant. Write the rule down and keep it fixed.
What is the difference between churn and retention?
They are two sides of one number. Churn rate plus customer retention rate equals 100% when both are measured on the same starting group.
Does a loyalty program reduce churn?
It can give customers a reason to return and it lets you see who stopped. Whether it lowers your churn is something to test by comparing members before and after launch, not to assume.
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