What the Churn Revenue Impact Calculator does
This calculator measures churn four ways - logo churn, gross revenue churn, net revenue churn, and the matching gross and net revenue retention (GRR and NRR) - then projects how much recurring revenue that churn costs over the coming months and how much a lower churn rate would save.
Monthly, quarterly and annual figures are converted by compounding rather than by multiplying or dividing, and all the arithmetic happens in your browser.
How to use it
- Choose the period your numbers cover: a month, a quarter or a year.
- Enter the customers you had at the start and how many of those left. Do not include customers won during the period.
- Enter MRR at the start and, from those same customers, the MRR lost to cancellations, the MRR lost to downgrades and the MRR gained from upgrades.
- Set a scenario churn rate and a projection length to see the revenue an improvement would protect.
- Download the month-by-month projection as CSV if you need it for a plan or a board paper.
Reading the results
Logo churn counts customers; revenue churn counts money. When revenue churn is lower than logo churn you are mostly losing small accounts; when it is higher, the accounts leaving are your larger ones.
Net revenue churn subtracts expansion. When it is negative (NRR above 100%), your existing customers grow on their own and every new sale adds to growth instead of replacing losses.
The projection follows only today's customers. It answers "what does churn cost us", not "what will MRR be", which also depends on new sales.
Worked example: a month where expansion outruns churn
A company starts the month with 400 customers and 100,000 of MRR. Twelve customers cancel (3% logo churn), taking 2,500 of MRR; downgrades remove another 500 and upgrades add 4,000.
Gross revenue churn is (2,500 + 500) / 100,000 = 3%, so GRR is 97%. Net revenue churn is (3,000 - 4,000) / 100,000 = -1%, so NRR is 101%. Annualised by compounding, NRR is 1.01^12 = 112.7% and GRR 0.97^12 = 69.4%.
Projected over 12 months at those rates, the existing base grows to about 112,683. With the same 4% monthly expansion and nothing lost it would reach about 160,103; summed month by month, the gap is roughly 281,751 of recurring revenue - the cost of churn and downgrades against that benchmark. Because the benchmark compounds expansion, treat it as an upper bound.
Formulas and scoring rules
- Logo churn
customers lost / customers at start- Gross revenue churn
(churned MRR + contraction MRR) / MRR at start- Net revenue churn
(churned + contraction - expansion) / MRR at startNegative values mean net expansion.- GRR and NRR
GRR = 1 - gross revenue churn; NRR = 1 - net revenue churn- Period conversion
monthly = 1 - (1 - r)^(1/months); annual = 1 - (1 - monthly)^12; NRR annual = NRR monthly^12- Projection
MRR_t = MRR_0 x (1 - gross + expansion)^t; lost_t = MRR_0 x (1 + expansion)^t - MRR_tRates are monthly. Percentages shown to 2 decimals, money to whole units.
Limitations: what the result does not prove
- Compounding assumes churn is spread evenly through the period. Annual renewals concentrate churn into renewal months, so monthly figures derived from annual ones are averages.
- The projection holds today's rates constant; in practice churn usually falls as surviving customers mature.
- It does not distinguish voluntary cancellations from failed payments. Involuntary churn is often cheaper to fix and worth measuring separately.
- Definitions vary between companies (for example whether downgrades to a free plan count as churn). Use the same definitions each period so trends are comparable.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
Frequently asked questions
How do I calculate customer churn rate?
Divide the customers lost during the period by the customers you had at the start of it. Exclude customers acquired during the period from both numbers, or new sign-ups will make churn look lower than it is.
What is the difference between GRR and NRR?
Gross revenue retention counts only losses, so it can never exceed 100%. Net revenue retention adds back expansion from the same customers and can exceed 100%. GRR shows how leaky the product is; NRR shows whether upsell covers the leak.
Can I multiply monthly churn by 12 to get annual churn?
No. Churn compounds on a shrinking base, so 3% a month is 1 - 0.97^12, about 30.6% a year, not 36%. The calculator converts every period by compounding and says so.
What does negative churn mean?
Negative net revenue churn means expansion revenue from existing customers exceeds what cancellations and downgrades take away. The customer base grows in value even with no new sales.
Should failed payments count as churn?
They cost you the same revenue, so most teams include them, but it helps to track them separately. Card updates and retry logic can recover much involuntary churn without any change to the product.
How much revenue does a one-point drop in churn save?
Enter the lower rate in the scenario box. The calculator re-runs the projection with your measured expansion and shows the difference in revenue lost over the months you choose.
Last reviewed by the A2Z.Tools team against the sources listed above.
