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Founder Churn Calculator

The Founder Churn Calculator measures customer churn and revenue churn over a selected period. It compares customers and recurring revenue lost during the period with the corresponding opening balances, allowing founders to see whether account losses and dollar losses tell the same story.

The tool is useful for monthly or quarterly retention reviews, especially when larger and smaller customers behave differently. Use one consistent period for every input. New customers and new revenue acquired during the period are not part of gross churn; expansion and reactivation are also excluded from the gross churn rates shown here.

Churn period inputs

USD
USD
Result
—
Customer churn rate
Gross revenue churn—
Customer retention—
Gross MRR retention—

1. Choose a reporting period
Use a consistent month, quarter, or other interval for every value.

2. Enter opening customers and MRR
Use the active customer count and recurring revenue at the start of the period.

3. Enter losses during the period
Count customers that fully churned and the recurring revenue removed by churn or contraction.

4. Compare customer and revenue churn
A higher revenue churn rate may indicate that larger accounts are leaving.

5. Review retention
The detail rows show the percentage of customers and MRR retained before expansion.

Customer churn rate = Lost customers ÷ Customers at period start × 100. Gross revenue churn = Lost MRR ÷ MRR at period start × 100.

What the result means

Customer churn shows the share of opening customers that left, while revenue churn shows the share of opening recurring revenue that was lost.

Use the same reporting period for all inputs and exclude customers added after the period began from the opening base.

Given: 220 starting customers, 11 customers lost, $19,000 starting MRR, and $1,350 lost MRR.

Calculation: Customer churn = 11 ÷ 220 × 100 = 5.00%. Revenue churn = $1,350 ÷ $19,000 × 100 = 7.11%.

Result: Customer churn is 5.00%, while gross revenue churn is 7.11%, suggesting lost accounts were above average in revenue.

Should downgraded customers count as churned customers?

A downgrade usually does not count as full customer churn, but the lost recurring amount can be included in gross revenue churn if contraction is part of your definition.

Can I include customers acquired during the period?

Do not add them to the starting denominator. Cohort and opening-base calculations are clearer when the denominator is fixed at the period start.

What if lost customers exceed starting customers?

That indicates inconsistent period definitions or data. The calculator rejects losses greater than the opening customer count.

How is churn different from retention?

For a simple gross calculation, retention equals 100% minus churn. Net revenue retention can exceed 100% because it includes expansion.

Should I use monthly or annual churn?

Use the period that matches your business cadence. Do not multiply a monthly churn rate by twelve when precise annual retention matters; compounding produces a different result.