Free calculator
Churn rate calculator and the retention rate formula
Work out customer churn, revenue churn and your retention rate, turn a monthly rate into an annual one without the usual mistake, and see how long customers stay.
Your numbers
Only customers who were there at the start.
Period
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Monthly churn
5.0%
50 of 1,000 customers left. Retention: 95.0%.
- Retention rate
- 95.0%
- Per quarter
- 14.3%
- Per year
- 46.0%
- Average lifetime
- 20 months
- Half of them gone in
- 13.5 months
- New customers needed a month
- 50
Share of today’s customers still with you
Quick answer
How do you calculate churn rate and retention rate?
Churn rate = customers lost in a period ÷ customers at its start. Retention rate = (customers at the end − new customers) ÷ customers at the start, which is 1 − churn. Start a month with 1,000 customers, add 80 and end with 1,030: you lost 50, so churn is 5% and retention 95%. Annualise by compounding: 1 − 0.95¹² = 46%, not 60%.
How to use the churn rate calculator
- Pick a mode
Customer churn counts accounts, revenue churn counts MRR, and Convert a rate turns a monthly, quarterly or annual rate into the others.
- Enter the period’s numbers
Use the customers or MRR you had on the first day of the period, and count only losses from that starting base. Pick month, quarter or year.
- Read the result
See churn and retention, the monthly and annual equivalents, average lifetime and how many new customers you need each month to stay flat.
- Share it
Copy the link to send the exact numbers to a cofounder or investor. Nothing is stored on our side.
How the calculator works
Churn rate is the share of a starting group that leaves during a period: customers lost divided by customers at the start. Retention rate is the share that stays. The classic retention formula, (customers at the end − new customers) ÷ customers at the start, gives the same number, because it strips out the customers you added.
Churn compounds. Each month’s churn applies to the customers who are left, so 5% a month leaves 0.95¹² = 54% of the starting group after a year: 46% annual churn. The calculator converts between months, quarters and years this way, in both directions.
Average lifetime is 1 ÷ monthly churn, so 5% a month means 20 months. Revenue churn works the same way on MRR: gross revenue churn counts cancellations and downgrades, net revenue churn subtracts the expansion you won from the customers who stayed.
Churn rate = customers lost ÷ customers at the start
Retention rate = (customers at the end − new customers) ÷ customers at the start = 1 − churn
Annual churn = 1 − (1 − monthly churn)^12
Monthly churn = 1 − (1 − annual churn)^(1/12)
Average lifetime (months) = 1 ÷ monthly churn
Gross revenue churn = (churned MRR + contraction MRR) ÷ starting MRR
Net revenue churn = (churned MRR + contraction MRR − expansion MRR) ÷ starting MRRWorked example
- Start of the month: 1,000 customers. 80 sign up and 1,030 are left at the end.
- Customers lost: 1,000 + 80 − 1,030 = 50.
- Churn: 50 ÷ 1,000 = 5.0%. Retention: (1,030 − 80) ÷ 1,000 = 95.0%.
- Annual churn: 1 − 0.95¹² = 1 − 0.540 = 46.0%, not 5% × 12 = 60%.
- Average lifetime: 1 ÷ 0.05 = 20 months. Staying at 1,000 takes 50 new customers a month.
Revenue churn benchmarks for B2B SaaS
Median gross revenue retention by annual contract value and contract length, from SaaS Capital’s 2025 survey of private B2B SaaS companies, with the revenue churn it implies.
| Annual contract value or contract | Median gross revenue retention | Annual revenue churn (100% − GRR) | Monthly equivalent |
|---|---|---|---|
| Under $12k | 90% | 10% | 0.87% |
| $12k to $25k | 91% | 9% | 0.78% |
| $25k to $50k | 91% | 9% | 0.78% |
| $50k to $100k | 90% | 10% | 0.87% |
| $100k to $250k | 91% | 9% | 0.78% |
| Over $250k | 95% | 5% | 0.43% |
| Month-to-month contracts | 89% | 11% | 0.97% |
| Annual contracts | 90% | 10% | 0.87% |
| Multi-year contracts | 94% | 6% | 0.51% |
| All companies | 91% | 9% | 0.78% |
Source: SaaS Capital, “2025 B2B SaaS Retention Benchmarks” (September 2025): more than 1,000 private B2B SaaS companies surveyed in Q1 2025, companies under $1M ARR excluded. Churn here is revenue churn, 100% − GRR, as SaaS Capital defines it; the monthly equivalent is our conversion with the formula above. Last verified October 27, 2026.
Why 5% monthly churn is 46% a year, not 60%
Churn compounds on a shrinking base. Month one takes 5% of 100 customers; month two takes 5% of the 95 who are left, not of the original 100. After twelve months 54% remain, so annual churn is 46%. Multiplying by 12 counts customers who already left, and the error grows with the rate.
| Monthly churn | Annual churn (compounded) | Monthly × 12 (wrong) | Average lifetime |
|---|---|---|---|
| 1% | 11.4% | 12% | 100 months |
| 2% | 21.5% | 24% | 50 months |
| 3% | 30.6% | 36% | 33.3 months |
| 5% | 46.0% | 60% | 20 months |
| 7% | 58.1% | 84% | 14.3 months |
| 10% | 71.8% | 120% | 10 months |
Customer churn vs revenue churn
Customer churn counts the accounts that leave; revenue churn counts the recurring revenue you lose, downgrades included. The two split apart when the customers who leave pay more or less than average. In David Skok’s example, losing 10 of 100 customers is 10% customer churn but only 3.4% revenue churn, because most of the lost accounts were small. Net revenue churn also subtracts expansion; below zero it is net negative churn, and revenue from your existing customers grows on its own.
Which customers to count
Divide by the customers you had on the first day of the period and count only the ones from that group who left. Customers who sign up and cancel inside the same month are real losses, but they were never in the starting base: report them separately or follow them in a cohort. For a quarter or a year, compound the monthly rate rather than dividing by a starting count that no longer reflects the business.
Churn rate questions
- What is the retention rate formula?
- Retention rate = (customers at the end of the period − new customers acquired in it) ÷ customers at the start × 100. Start with 200, add 30 and end with 210: (210 − 30) ÷ 200 = 90% retention, so churn is 10%.
- How do you calculate churn rate?
- Divide the customers you lost during a period by the customers you had at its start. 25 cancellations from 500 starting customers is 25 ÷ 500 = 5% churn for that period.
- How do you convert monthly churn to annual churn?
- Compound it: annual churn = 1 − (1 − monthly churn)¹². 3% a month is 1 − 0.97¹² = 30.6% a year. To go the other way, monthly churn = 1 − (1 − annual churn)^(1/12).
- Why can’t I multiply monthly churn by 12?
- Because each month’s churn applies to the customers who are left, not to the original group. Multiplying by 12 counts customers who already left. At 5% a month it says 60% a year; the real figure is 46%.
- What is a good churn rate for SaaS?
- SaaS Capital’s 2025 survey of private B2B SaaS companies found median gross revenue retention of 91%: about 9% annual revenue churn, under 1% a month. David Skok treats net revenue churn above 2% a month as a sign that something is wrong.
- What is the difference between customer churn and revenue churn?
- Customer churn counts accounts that leave; revenue churn counts the recurring revenue lost, including downgrades. If small customers leave, revenue churn is lower than customer churn; if your largest accounts leave, it is higher.
- What is net negative churn?
- Net revenue churn below zero: expansion from the customers who stay is larger than the revenue lost to cancellations and downgrades. Revenue from your existing customers then grows with no new sales, which is net revenue retention above 100%.
- How do you calculate customer lifetime from churn?
- Average lifetime in months = 1 ÷ monthly churn. At 4% monthly churn the average customer stays 1 ÷ 0.04 = 25 months. Halve churn and you double the lifetime, and with it lifetime value.
- Is my data stored?
- No. The calculator runs in your browser and sends nothing to SaaSCity. The share link puts your numbers in the URL, so only people you send it to see them.
Cite this tool
Free to link and quote. Use this reference:
SaaSCity, "Churn Rate Calculator", October 27, 2026. https://saascity.io/free-tools/churn-rate-calculator