How to Calculate Customer Retention Rate (Formula + Examples)

Customer retention rate is the percentage of customers a business keeps over a defined period. It is the single most reliable indicator of product-market fit, customer success effectiveness, and long-term enterprise value. Yet most teams calculate it incorrectly — either using the wrong formula, the wrong period, or comparing numbers that aren't actually comparable.

This guide gives you the exact formula, three worked examples across SaaS, ecommerce and agencies, and the mistakes that quietly distort the number on most dashboards. If you're trying to set a benchmark target, our companion piece on client retention strategies covers benchmarks by industry.

How to calculate customer retention rate: the formula

The standard customer retention rate formula is:

CRR = ((E − N) / S) × 100

Where S is the number of customers at the start of the period, E is the number of customers at the end of the period, and N is the number of new customers acquired during the period. Subtracting N is the critical step — without it, you're measuring net growth, not retention.

The output is a percentage. A CRR of 92% means 92% of the customers you started the period with were still customers at the end. The inverse (100% − CRR) is your churn rate.

Retention rate calculation: a worked example

Suppose a B2B SaaS company starts Q1 with 500 customers. During the quarter, it acquires 80 new customers. At the end of Q1, it has 540 customers. The retention rate is:

((540 − 80) / 500) × 100 = (460 / 500) × 100 = 92%

Net customer count grew by 40 (a healthy headline), but 40 customers churned during the quarter — 8% of the starting base. Both numbers matter, and conflating them is the most common reporting error we see.

How to calculate retention rate for ecommerce (repeat purchase rate)

Ecommerce doesn't have a clean 'customer count' at any point in time — buyers are defined by behaviour, not status. The ecommerce equivalent is repeat purchase rate: the percentage of customers in a given cohort who place a second order within a defined window.

Repeat purchase rate = (Customers with 2+ orders in window / Total customers acquired in window) × 100

For a DTC brand that acquired 1,000 first-time buyers in January, if 280 of them placed a second order within 90 days, the 90-day repeat purchase rate is 28%. Top-quartile DTC brands hit 35–50%; below 25% usually signals a product, post-purchase or merchandising problem.

How to calculate retention rate for SaaS: logo vs revenue retention

SaaS reports two retention numbers, and you need both:

Logo retention (also called customer retention) uses the formula above and counts customers as units. Net revenue retention (NRR) weights by contract value and includes expansion: ((Starting MRR + Expansion MRR − Churned MRR − Contraction MRR) / Starting MRR) × 100.

A SaaS business can have 88% logo retention and 115% NRR simultaneously — meaning small customers churn but large ones expand. Public SaaS leaders typically report NRR above 120% and gross logo retention above 90%.

Calculate retention rate the right way: common mistakes

Mistake 1 — Mixing periods. Comparing this quarter's monthly retention rate to last quarter's annual retention rate produces meaningless numbers. Pick a period and stick with it.

Mistake 2 — Forgetting to subtract new customers. Without subtracting N from E, you're measuring net growth, which can mask catastrophic churn during a high-acquisition month.

Mistake 3 — Counting paused or downgraded customers as retained. A customer who downgraded from a $5,000/month contract to $200/month is technically retained but represents 96% revenue churn on that account. Track both logo and revenue retention to catch this.

Mistake 4 — Using rolling averages without cohort analysis. A 90% blended retention rate can hide a 70% retention rate on a specific acquisition channel that's pulling the whole business down. Cohort analysis exposes which segments are actually healthy.

Retention rate definition: what it measures, what it doesn't

Retention rate measures whether customers stay. It does not measure whether they're happy, whether they're profitable, or whether they'll refer others. A high retention rate on an unprofitable customer base is still bad business — it just means your churn isn't being driven by overt dissatisfaction.

Pair retention with net revenue retention, NPS or CSAT, and gross margin per customer to get a complete picture. If you're rebuilding your measurement stack, our guide on client retention strategies walks through the operating model that drives these numbers.

Frequently asked questions

What is the customer retention rate formula? The standard formula is ((E − N) / S) × 100, where S is customers at the start of the period, E is customers at the end, and N is new customers acquired during the period. The result is the percentage of starting customers who remained.

What is a good customer retention rate? It depends on business model. SaaS targets 90%+ annual logo retention and 110%+ net revenue retention; ecommerce DTC brands target 28–35% annual repeat purchase rate; agencies target 80–90% annual account retention. Below those bands usually signals a fixable operational problem.

How do I calculate retention rate in Excel? In a single cell: =((E − N) / S) × 100, where E, N and S are the cells holding your end-of-period customers, new customers acquired, and start-of-period customers. For cohort analysis, use a pivot table that groups customers by acquisition month and counts who remained in subsequent months.

What's the difference between retention rate and churn rate? They're mathematical inverses. If your annual retention rate is 88%, your annual churn rate is 12%. Retention rate is the more useful framing for goal-setting (you want it to go up); churn rate is more useful for diagnosing problems (you want to know which segments are leaving).

Should I measure monthly or annual retention? Both. Monthly retention catches problems early and is the right cadence for SaaS and subscription businesses. Annual retention smooths seasonality and is the right cadence for board reporting and benchmarking against industry peers.

For a deeper look at industry benchmarks, formulas, and the strategic levers that move the client retention rate metric across SaaS, ecommerce, healthcare, and professional services, see our pillar guide on what client retention rate is and how to improve it.