# Customer Retention Rate Calculator

URL: https://speedycalculator.com/calculators/finance/customer-retention-rate/
Last updated: 2026-10-25

> The customer retention rate calculator works out the percentage of existing customers you kept over a period, excluding new customers won during it, and the matching churn (attrition) rate.

## Inputs

- Customers at the start
- New customers during the period
- Customers at the end

## Results

- Customer retention rate
- Attrition (churn) rate
- Customers lost

## Formula

```
Retention rate = (customers at end − new customers) ÷ customers at start × 100
Churn rate = 100% − retention rate
```

## Explanation

Customer retention rate isolates loyalty: new customers are removed so that strong acquisition cannot hide poor retention. Increasing retention by a few percentage points can raise profit sharply because existing customers cost less to serve.

### How to use the Customer Retention Rate Calculator

- **Customers at the start**
- **New customers during the period**
- **Customers at the end**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the number of customers at the start of the period, at the end, and the new customers gained during it.

### Tips

- Use figures for the same period (a month, a quarter or a year) for every input so ratios compare like with like.
- Track the metric over time – the trend usually tells you more than a single value.
- Compare your result with industry benchmarks, which vary a lot between sectors.
- Treat the result as a starting point for a decision, then check the assumptions behind each input.

### Common mistakes to avoid

- Mixing monthly and yearly numbers in the same calculation.
- Using revenue where the formula needs profit (or the other way round).
- Forgetting hidden costs such as taxes, fees, overheads or your own time.

### Inputs explained

FieldWhat to enterCustomers at the startA numberNew customers during the periodA numberCustomers at the endA number

### What each result means

- **Customer retention rate** = ([Customers at the end] - [New customers during the period])÷[Customers at the start]×100
- **Attrition (churn) rate** = 100 - [Customer retention rate]
- **Customers lost** = [Customers at the start] - ([Customers at the end] - [New customers during the period])

### Example values

How the main result changes when **Customers at the start** changes and everything else stays at the example values above:

Customers at the startCustomer retention rate (%)250184375122.675009262573.675061.331,00046

## Worked example

Inputs — Customers at the start: 500; New customers during the period: 80; Customers at the end: 540.

Results — **Customer retention rate = 92 %**; Attrition (churn) rate = 8 %; Customers lost = 40.

## FAQ

**What is a good customer retention rate?**
It varies: around 80% or more is strong in many B2B markets.

**Why subtract new customers?**
So you measure how many existing customers stayed, not how many you added.

**How can I improve retention?**
Better onboarding, service, loyalty rewards and listening to feedback.

**What formula does the Customer Retention Rate Calculator use?**
Retention rate = (customers at end − new customers) ÷ customers at start × 100.