FinToolSuite

SaaS Churn Rate Calculator

Updated April 17, 2026 · Financial Health · Educational use only ·

Customer churn metrics.

Calculate SaaS monthly and annualized churn rate, lost MRR, and average customer lifetime. Enter customers start of month and see the result instantly.

What this tool does

This tool calculates monthly churn rate, annualized churn, lost MRR, and average customer lifetime from starting customers, churned customers, and average MRR.


Enter Values

Formula Used
Customers churned
Customers at start

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Monthly churn is the percentage of customers who cancel each month. Divide cancellations by the month-start count. A 3% monthly churn sounds small but annualises to 31% - a third of the customer base gone every year. Below 1% monthly is excellent, 1-3% is healthy, 3-5% is stretched, above 5% a SaaS is usually in trouble.

Starting with 1,000 customers and losing 30 during the month = 3% churn. Annualised that's 30.6% customer loss. At 50 average MRR per customer, lost MRR is 1,500/month or 18k/year. Average customer lifetime is 1/churn = 33 months or 2.8 years.

Churn compounds fast. A SaaS adding 100 new customers/month with 5% churn on a 1,000 customer base nets only 50 new customers (100 gross - 50 churned). At 2% churn, the same 100 gross becomes 80 net. The churn rate change from 5% to 2% triples sustainable growth rate.

Run it with sensible defaults

Using customers start of month of 1,000, customers churned of 30, avg mrr per customer of 50, the calculation works out to 3.00%. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Customers Start of Month, Customers Churned, and Avg MRR per Customer — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

Monthly churn = churned ÷ start × 100. Annualized = 1 - (1 - monthly)^12. Lifetime = 1 ÷ monthly churn. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this as a check-in

Re-run this every three months. A single reading tells you where you stand; four readings tell you whether things are improving. The trend matters more than any individual snapshot.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.

Example Scenario

30 customers churned ÷ 1,000 starting = 3.00%.

Inputs

Customers Start of Month:1,000
Customers Churned:30
Avg MRR per Customer:50 £
Expected Result3.00%

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Monthly churn = churned ÷ start × 100. Annualized = 1 - (1 - monthly)^12. Lifetime = 1 ÷ monthly churn.

Frequently Asked Questions

What's a good monthly churn rate?
SMB SaaS: 3-7% is typical, under 3% is strong. Mid-market: 1-3% typical, under 1% is world-class. Enterprise: under 0.5% common, contracted multi-year deals often near zero logo churn.
Is revenue churn more important than logo churn?
Yes usually. Revenue churn accounts for size: losing 10 small customers hurts less than losing 1 large one. Best SaaS companies report 'net revenue retention' - if expansion in remaining customers exceeds churn, NRR is above 100% and the business grows even without new sales.
Why annualize differently?
Compound math: losing 3% monthly isn't losing 36% annually - it's losing 31% because each subsequent month applies to a smaller base. Some companies misleadingly quote monthly churn × 12 to look better; the compound formula is standard.
How do I reduce churn?
Onboarding is the biggest lever - customers who reach first-value in the first 30 days churn far less. Annual contracts reduce churn 30-50% vs monthly. Usage-based pricing aligned with customer value reduces churn because growing customers pay more willingly.

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