MRR & Churn Simulator — BlackBox Society

Inputs

This is intentionally "dumb but useful": constant churn rate, constant average revenue per account, constant new customers per month.

Scenario preset

Pick a preset to auto-fill inputs, then tweak.

Starting customers

Customer count at month 0.

ARPA ($/month)

Average revenue per account, per month.

New customers / month

Assumes adds occur after churn within each month.

Monthly churn (%)

Example: 3 means 3% of customers churn each month.

Months to simulate

Keeps output small; export CSV if needed.

Gross margin (%) (optional)

Used for LTV (gross-profit basis). Set to 100 to ignore.

CAC ($) (optional)

If set, we show a rough payback period estimate.

Model

Revenue churn applies churn% to MRR directly; useful if accounts have expansion/contraction.

Tip: use “Copy share link” after tweaking inputs.

No network calls. All math is in your browser. Beware: projections are not predictions.

Month 0 MRR

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Final month MRR

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Final month customers

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Implied LTV (gross profit)

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CAC payback (months)

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Rules of thumb:

LTV here is approximated as (ARPA × grossMargin) / churn (monthly churn as a fraction).
If churn is 0, LTV is undefined (tool will show “∞”).

Month	Customers	Churned	New	MRR ($)