# Customer Retention Rate Calculator

> Calculate customer retention rate from customers at the start and end of a period and new customers gained, with churn and customers lost.

Category: Commerce & retail · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/customer-retention-rate-calculator

Retention rate is the share of the customers you started with who are still customers at the end. New customers are subtracted first so growth does not hide losses.

Also called: CRR calculator, Retention rate calculator.

## Inputs
- Customers at the start (S) (default 1000)
- Customers at the end (E) (default 1100)
- New customers during the period (N) (default 250)

## Results
- Customer retention rate
- Churn rate
- Customers retained
- Customers lost
- Net customer growth

## Formula

```
Retention rate = (E − N) ÷ S × 100;  Churn = 100 − Retention
```

Where:
- S: customers at the start of the period
- E: customers at the end
- N: new customers acquired during the period

## Worked example
1. Retained = 1,100 − 250 = 850.
2. Retention = 850 ÷ 1,000 = 85%.
3. Churn = 100 − 85 = 15%, or 150 customers lost.

**Result:** The business kept 85% of its starting customers and lost 15%, even though the total grew by 10%.

## What the result means

Compare retention only over equal periods and with the same definition of an active customer. For non-subscription shops, define “customer” as someone who bought within a set window, such as the last 12 months.

## Assumptions and limits
- New customers acquired during the period are not counted as retained.
- It is a single-period figure; cohort analysis shows how retention changes with customer age.

## Questions

### Why subtract new customers?

Otherwise acquisition can mask losses. Subtracting them leaves only the customers you started with.

### What counts as a customer in a non-subscription shop?

Choose a rule, such as purchased in the last 12 months, and apply it to both the start and end counts.

## Related calculators
- [Subscription Churn Calculator](https://calculators.geekmidst.com/calculators/subscription-churn-calculator)
- [Customer Referral Reward Calculator](https://calculators.geekmidst.com/calculators/customer-referral-reward-calculator)
- [Percentage Calculator](https://calculators.geekmidst.com/calculators/percentage-calculator)
- [Employee Retention Rate Calculator](https://calculators.geekmidst.com/calculators/employee-retention-rate-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/customer-retention-rate-calculator