Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Monthly customer churn
3.45%
Annualised churn
34.4%
Gross revenue churn
2.84%
Net revenue retention
101.8%
Monthly retention
96.55%
Average lifespan (months)
29.0
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter customers at start of month.
- 2Enter customers lost.
- 3Enter starting mrr ($).
- 4Enter mrr churned ($).
- 5Enter expansion mrr ($).
- 6Read your monthly customer churn on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Logo churn counts customers; revenue churn counts dollars. When expansion revenue from existing accounts exceeds what churns, net revenue retention goes above 100% and the business grows without adding a single customer.
Worked example
Using the values the calculator loads with:
Inputs
- Customers at start of month: 840
- Customers lost: 29
- Starting MRR: 74000 $
- MRR churned: 2100 $
- Expansion MRR: 3400 $
Results
- Monthly customer churn: 3.45%
- Annualised churn: 34.4%
- Gross revenue churn: 2.84%
- Net revenue retention: 101.8%
- Monthly retention: 96.55%
- Average lifespan (months): 29
What each field means
Inputs
- Customers at start of month
- The customers at start of month used in the calculation. Starts at 840 so you have a working example on load.
- Customers lost
- The customers lost used in the calculation. Starts at 29 so you have a working example on load.
- Starting MRR ($)
- The starting mrr used in the calculation, measured in $. Starts at 74000 $ so you have a working example on load.
- MRR churned ($)
- The mrr churned used in the calculation, measured in $. Starts at 2100 $ so you have a working example on load.
- Expansion MRR ($)
- The expansion mrr used in the calculation, measured in $. Starts at 3400 $ so you have a working example on load.
Results
- Monthly customer churn
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annualised churn
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Gross revenue churn
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net revenue retention
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly retention
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Average lifespan (months)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the churn rate calculator work?
Logo churn counts customers; revenue churn counts dollars. When expansion revenue from existing accounts exceeds what churns, net revenue retention goes above 100% and the business grows without adding a single customer. The underlying maths is: Churn = Lost ÷ Starting count. NRR = (Start + Expansion − Churned) ÷ Start.
What do I need to enter?
5 values: customers at start of month, customers lost, starting mrr, mrr churned, and expansion mrr. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the monthly customer churn result mean?
It is returned as a percentage and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Churn Rate Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/churn-rate
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/churn-rate" target="_blank" rel="noopener">Churn Rate Calculator — RevenueLab</a> (2026).</p>
Source: [Churn Rate Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/churn-rate) (2026).