Customer retention: what it is, how to measure it and how to improve it
What customer retention is, how to calculate the retention rate and how it differs from churn and LTV. Plus three signs customers leave, and where to start.
Customer retention is the share of customers who stay with a company or buy again, instead of buying once and leaving. It is measured by the retention rate: customers who stayed at the end of the period, divided by customers at the start of the period, times 100. The opposite is churn, the share of customers who left; together they always add up to 100 %. To start improving it, measure how many customers bought more than once in the last 12 months, and take care of the first 30 days after the first purchase.
Ads bring visitors. Some of them buy. And then nothing. Next time they buy elsewhere, or not at all. And you pay again for a new customer, even though winning the previous one took so much work.
That is called a customer retention problem. Retention is a word marketing uses constantly, yet few people can say precisely what it means or how it is calculated. This article explains both: what customer retention is and how to measure it, then how to tell that your customers are leaving too early, and where to start fixing it.
What is customer retention: a simple definition
Customer retention is a company’s ability to keep a customer, so that they buy repeatedly or stay on, instead of buying once and leaving. It is not measured by the feeling that “customers come back to us”, but by the concrete share of customers who returned in a given period.
The word retention itself means holding on to or keeping something (from the Latin retentio). That is why it shows up in different fields with different meanings: in HR it means keeping employees, in medicine the body holding on to fluids. In marketing and business, retention means keeping customers.
What exactly counts as retention differs by business:
- E-commerce: a customer who buys a second time, and then again
- SaaS: a customer who renews their subscription when the billing cycle ends
- Services with recurring billing: a customer who does not cancel the contract
- Project-based services: a customer who comes back with another brief
Without that definition, retention cannot be managed. It just gets discussed in meetings and never shows up in the numbers.
Retention rate: the metric that turns retention into a number
Retention on its own is a state (the customer stayed, or left). To work with it, you need to relate it to the total number of customers at the start of the period. That gives you the retention rate:
customers at the end of the period who stayed ÷ customers at the start of the period × 100 = retention rate (%)
If a company started the quarter with 200 customers and 140 of them were still there at the end (not counting newly acquired ones), the retention rate is 70 %. Where exactly a “good” retention rate starts varies so much by industry that a rough benchmark would be misleading. What makes sense is tracking your own number over time, not comparing it with a different industry.
Churn, LTV, repeat purchase: the terms that get confused with retention
Churn rate: retention’s mirror image
Churn rate is the complement of the retention rate to 100 %. If the retention rate is 70 %, churn is 30 %. It is the same information seen from the opposite side. Companies still track both, because each one explains something different better: retention works for “how much we keep”, churn for “how much we are losing”.
Lifetime value (LTV): a customer’s worth across the whole relationship
Customer lifetime value (LTV for short) tells you how much money a customer brings the company in total, not just on the first purchase. Retention and LTV are directly linked: the longer a customer stays, the higher their LTV.
Repeat purchase: a single event, not a relationship metric
A repeat purchase is a one-off action (a second, third order). Retention is the state of the relationship over a longer period. A customer can make one repeat purchase and still leave in the next period. Retention tracks whether they stay, not just whether they bought again once.
Quick glossary
| Term | What it means | Example |
|---|---|---|
| Retention | Share of customers who stayed in a period | 70 % |
| Retention rate | Retention expressed as a percentage | 140 of 200 = 70 % |
| Churn rate | The complement of retention to 100 %: how many customers left | 30 % |
| LTV | Total value of a customer over the relationship | The sum of all their purchases |
| Repeat purchase | A single second-or-later purchase event | The second order |
| Cohort | A group of customers who share a first-purchase month | January’s customers |
What is retention marketing?
Retention marketing is everything a company does to bring back customers it has already won, instead of looking for new ones. Acquisition marketing pays for someone new to hear about the company; retention marketing works with people who have already bought and whose contact details the company already has.
Typical retention marketing tools:
- Post-purchase emails: a thank-you, how-to instructions, a reminder when a consumable is running out
- Loyalty programs and perks for regular customers: points, a discount on the next purchase, early access to new products
- Personalized offers: recommendations based on previous purchases
- Reactivation: reaching out to customers who have not bought in a while
The success of retention marketing is not measured by email open rates, but by what this article describes: the retention rate, the share of repeat purchases and how LTV develops across cohorts. A campaign customers enjoy reading but never buy again from does not increase retention.
Retention marketing also starts earlier than most companies think. A first purchase that went through without needless friction is the best starting point for the second one.
How to measure retention properly
1. Pick a period that matches your sales cycle. An e-commerce store with fast-moving goods measures monthly; a B2B service on annual contracts measures yearly. The wrong period distorts the picture: monthly retention on annual contracts will look artificially high.
2. Track cohorts, not just the overall number. A cohort is a group of customers who share a first-purchase month. The overall retention rate can look stable while it is actually improving for new customers and getting worse for older ones. Cohorts show that difference; the overall number hides it.
3. The data lives in your CRM, billing system or e-commerce platform. Look at how many customers from a given cohort bought (or renewed their subscription) in the following period. Which tool that is depends on the business: for SaaS it is usually the subscription status, for e-commerce the order history by email or account.
Why retention is cheaper than acquisition
Winning a new customer costs five to seven times more than keeping an existing one. Almost everyone knows that number, yet in practice companies give retention nowhere near the attention they give acquisition.
The reason is simple: acquisition is visible. You pay for ads, watch clicks, measure cost per conversion. The numbers are immediate and concrete. Retention, on the other hand, is invisible: a customer leaving shows up in the data quietly, with no alert and no clear cause. They simply stop buying, and you find out months later, if at all.
Yet it is one of the biggest financial levers you have. A customer who comes back three times is worth substantially more than three different customers: they buy without ad spend, convert more easily and recommend you to others.
How to tell that customers are leaving too early
A customer retention problem rarely announces itself. It hides behind a growing count of new customers, behind the familiar “traffic is up” or “this month was good”. Three signals worth paying attention to:
Purchases don’t repeat. Look at how many of last year’s customers bought again. If it is a clear minority, you have a retention problem, no matter how well your first orders are growing.
Revenue only grows when ad spend grows. Raise the budget and more customers arrive. Cut it and revenue falls straight back. A healthy business keeps part of its revenue even without continuous advertising, from returning customers. Without that component, you depend on ads.
Cohorts look like an hourglass. If you track how many people from the January cohort bought in February, March and April, and the numbers drop sharply right after the first purchase, the signal is clear. Customers leave before you have recovered the cost of winning them.
What kills retention most often
The customer doesn’t know how to come back. The first purchase goes fine. The customer is satisfied. But the company sends no follow-up, offers no reason to return, never gets back in touch. Time passes and the customer forgets you, not because they were unhappy, but because nobody reminded them of you. What to write to a customer at that moment, and how, is a copy question; we covered how to write copy that sells and keeps interest separately.
Onboarding ends at the first purchase. This is especially true for digital products and services: the customer has to feel the value early enough and strongly enough to come back. If their first experience wasn’t great, or came without any context, the barrier to a second purchase is too high. For SaaS this is decided during the trial already, see why free trial users don’t buy.
It isn’t clear why to come back to you in particular. If the customer sees your product as interchangeable with the competition, they have no reason to be loyal. They will buy wherever it is cheaper or wherever an ad reaches them first. Content marketing can help a lot here, but only if it is set up right. What to do so your blog actually brings returning customers is explained in our article on blog conversions.
What we found on a real project
We worked with a digital platform that had a steady inflow of new customers. Traffic was up, first conversions were up. The numbers looked good.
But when we looked at the cohorts, the picture changed. From each cohort, only a small share returned the following month. Most customers bought once and never showed up again. The platform was growing on paper only: acquisition costs were rising, customer lifetime value was stagnating.
The cause wasn’t the product. Customers who did return were satisfied. The problem was what happened, or rather didn’t happen, after the first purchase: no follow-up, no personalization, nothing that gave the customer a reason to come back.
How to increase customer retention: where to start
First, find out where you stand. Look in your data (e-commerce platform, CRM, billing system) and work out how many customers bought more than once in the last 12 months. If you don’t have that number, start there.
Ask the customers who came back. Not the ones who left, they won’t answer. But customers who bought a second time will tell you why. Their answers show what your retention rests on and what needs strengthening.
Take care of the first 30 days. If a customer doesn’t find value in the first month, the chance they return drops sharply. An email sequence, a follow-up after the first purchase, relevant content or a discount on the second purchase are basic tools that cost almost nothing. But it also matters how the first purchase went on the website: a customer who ran into needless obstacles comes back less willingly. We covered the five most common conversion barriers that spoil even the first purchase separately.
Measure customer cohorts, not just total revenue. Total revenue tells you how the company looks today. Cohorts tell you how it will look in six months.
What retention is not: two common mistakes
A high number of new customers isn’t retention. A company can win dozens of new customers a month and still have a retention problem if existing ones leave at the same rate. Growing revenue from acquisition hides a retention problem for a long time.
Satisfaction isn’t retention. A customer can rate the experience positively and still not come back, because nobody gave them a reason or an occasion to return. Retention is measured by behavior (did they come back or not), not by an opinion in a satisfaction survey.
Frequently asked questions about customer retention
What does customer retention mean?
Retention means a company keeps its customers, so they keep buying or stay on. It is measured as the share of customers who did not leave in a given period, not by gut feeling or satisfaction.
What does the word retention mean?
In general, retention means holding on to or keeping something (from the Latin retentio). In marketing and business it means keeping customers, in HR keeping employees, and in medicine the body holding on to fluids.
What is the difference between retention and churn?
They are complementary metrics. Retention tells you how many customers stayed (as a percentage), churn tells you how many left. The two always add up to 100 %.
How is the retention rate calculated?
The number of customers who were still with the company at the end of the period, divided by the number of customers at the start of that same period, times 100.
How do you increase customer retention?
First, measure how many customers bought more than once in the last 12 months. Then ask the ones who came back why they did. Finally, take care of the first 30 days after the first purchase: a follow-up, relevant content, a reason to come back.
What is retention marketing?
Retention marketing is everything a company does to bring back customers it has already won: post-purchase emails, loyalty programs, reminders and offers for existing customers. Unlike acquisition marketing, it does not target new people, and its success is measured by the retention rate and repeat purchases.
Why does retention matter for revenue?
A customer who stays longer has a higher lifetime value (LTV) and does not require repeated acquisition spend on ads. Raising retention is therefore usually a cheaper way to grow revenue than winning new customers.
The takeaway
Customer retention is a concrete, measurable share of customers who stay with a company, not a vague sense of loyalty. Before you start improving it, define what retention means in your business, pick the right period and start tracking cohorts instead of one overall number.
Retention starts with the first purchase going smoothly. If you want to know where exactly customers drop off on your website and in your funnel, that’s exactly what Kaen watches: he finds the step where people drop off, builds the variations and, once you approve, runs the A/B test.