SaaS Churn Rate: How to Calculate It Right (Monthly vs Annual)

Churn rate is the share of customers — or revenue — you lose over a period: churn = lost ÷ starting base. To convert monthly churn to annual, use annual = 1 − (1 − monthly)^12, never monthly × 12, because churn compounds on a shrinking base.

That second sentence is where most SaaS dashboards quietly go wrong. Multiply a 3% monthly churn rate by 12 and you get 36% annual churn. The real number is 30.6%. That five-point gap flows straight into your LTV, your retention forecasts, and every board slide built on top of them. This guide covers the formula, the monthly-vs-annual conversion done right, customer vs revenue churn, cohort traps, and where your number should sit against 2026 benchmarks.

The churn rate formula (both flavors)

Customer churn (logo churn)

Customer churn is the count-based version:

Customer churn rate = customers lost during period ÷ customers at start of period

Start January with 400 customers, lose 12 during the month: 12 ÷ 400 = 3% monthly customer churn. The denominator is the starting count. Customers who signed up mid-month don't belong in it — more on that in the cohort section.

Revenue churn (MRR churn)

Revenue churn weights each loss by what the customer paid:

Gross revenue churn rate = MRR lost to cancellations and downgrades ÷ MRR at start of period

Note the word gross. Expansion revenue from surviving customers does not offset churned MRR in this metric — netting them out is what Net Revenue Retention is for. Churn should always be reported gross, so you can see the leak before the patch.

Monthly vs annual: the compounding mistake

Churn compounds because each month you lose a percentage of a base that last month's churn already shrank. Lose 3% of 400 customers in January and you're losing 3% of 388 in February, not 3% of 400 again. Simple multiplication assumes the base never shrinks — which is exactly the thing churn does.

The correct conversions:

• Monthly → annual: annual churn = 1 − (1 − monthly churn)^12
• Annual → monthly: monthly churn = 1 − (1 − annual churn)^(1/12)

Worked example: 3% monthly churn

Start with 1,000 customers and 3% monthly customer churn.

1. Monthly retention = 1 − 0.03 = 0.97
2. Twelve months of compounding: 0.97¹² = 0.694 — you keep 69.4% of the cohort
3. Annual churn = 1 − 0.694 = 30.6%

So after a year you have 694 of those 1,000 customers left — not the 640 the naive "36% annual churn" math implies. The gap widens as churn rises: 5% monthly is 46.0% annual, not 60%.

The error cuts the other way too. A team told to hit "20% annual churn" that divides by 12 sets a monthly target of 1.67%. The correct monthly equivalent is 1 − 0.80^1/12 = 1.84%. Naive division just handed the retention team a target roughly 10% harsher than the one leadership actually set.

And it contaminates downstream metrics. LTV divides margin-adjusted ARPA by churn — plug in 36% when the truth is 30.6% and you've understated customer lifetime value by about 15%, which quietly distorts every LTV:CAC decision you make. The churn rate calculator does the compounding conversion in both directions so nobody on your team has to remember which exponent goes where.

Customer churn vs revenue churn: two different stories

The two rates diverge whenever your customers aren't all the same size — which is every SaaS with more than one pricing tier.

Take that 400-customer company at $60,000 MRR. It loses 12 customers in a month, all on the $49 starter plan: customer churn is 3%, but revenue churn is $588 ÷ $60,000 = under 1%. Healthy business shedding low-fit small accounts.

Now flip it. The same company loses just 3 customers — 0.75% logo churn, apparently excellent — but one of them is a $5,000/month enterprise account. Revenue churn: $5,098 ÷ $60,000 = 8.5%. Same "low churn" headline, existential problem underneath.

The operating rule: track both, never blend them. Customer churn tells you how well the product retains users; revenue churn tells you how well the business retains money. Investors will look at revenue churn first, then at gross revenue retention — its mirror image — to see your retention floor before expansion dresses it up.

What good looks like in 2026

For monthly gross revenue churn: under 1% is excellent, under 2% is healthy, 2–3.5% is around the B2B SaaS median, and above 3.5% is a fire to fight before you spend another dollar on acquisition. SMB-heavy books naturally run hotter than enterprise. Stage-level medians, with the annualized equivalents computed correctly:

Stage	Monthly revenue churn (median)	Annualized equivalent	Read
Bootstrapped	~3.0%	~30.6%	Around median
Seed	~3.5%	~34.8%	Around median — watch it
Series A	~2.5%	~26.2%	Around median
Series B+	~1.5%	~16.6%	Healthy

Directional 2026 medians synthesized from public SaaS benchmark reports (SaaS Capital, Benchmarkit/KeyBanc, Bessemer). Sources vary by segment, ACV, and survey methodology — treat these as orientation, not gospel. The full set of retention and efficiency bands lives on the benchmarks page.

Notice the table's annualized column uses the compounding formula. If it had used ×12, Seed-stage churn would read 42% instead of 34.8% — a completely different narrative from the same underlying number.

Cohort pitfalls: when the blended rate lies to you

Fast growth masks bad retention

Churn is highest in a customer's first few months. If you're adding customers quickly, most of your base is young — too new to have churned yet — and your blended churn rate looks great even while every individual cohort bleeds out on schedule. The blended number improves because you're pouring new customers into the top, not because retention got better. Cut churn by cohort (customers grouped by signup month) and read retention at month 1, 3, 6, and 12. If each cohort's curve looks the same as the last one's, your retention hasn't improved — your mix has.

Annual contracts create a churn mirage

A customer on a 12-month contract cannot churn in months 1–11, no matter how much they hate the product. Monthly churn on an annual-heavy book looks fantastic right up until the renewal cliff. Measure churn against the renewable base — only the contracts actually up for renewal in the period — or you're computing the churn rate of customers who had no exit door.

Denominator pollution

Adding mid-period signups to the denominator dilutes the rate: lose 12 of 400 starting customers but count the 40 who joined mid-month, and 3% churn becomes 2.7% by arithmetic sleight of hand. Fix the denominator at the period start, every period, and never change the definition between reports.

Common mistakes, ranked by damage

1. Multiplying monthly churn by 12 (or dividing annual by 12). The compounding error this whole guide exists to kill. Overstates annual churn, understates LTV, misprices your unit economics.
2. Averaging monthly rates across a year. Twelve monthly rates averaged arithmetically ignore compounding too. Compound the retention rates, then subtract from 1.
3. Netting expansion against churn. That produces net churn — a fine metric, but it's NRR wearing a churn costume. Report gross churn so the leak is visible.
4. Ignoring involuntary churn. Failed cards and expired payment methods routinely account for 20–40% of gross churn. It's the cheapest churn to fix (dunning, card updaters) and most teams don't even segment it.
5. Counting trials and free users in the base. A free user who leaves didn't churn — they never converted. Paid base only.
6. Blending customer and revenue churn in one KPI. They answer different questions; a blended number answers neither.
7. Redefining the denominator when it flatters you. Pick start-of-period, write it down, never revisit it in a good month.

Run your numbers

The math isn't hard — it's just unforgiving of shortcuts. Compute customer and revenue churn separately from a fixed starting base, convert between monthly and annual with the compounding formula, and check cohorts before you trust the blended rate. Then benchmark: if your monthly revenue churn is above 2%, retention work will likely return more than another dollar of acquisition spend.

The free churn rate calculator handles both churn types and both conversion directions, and scores your result against the same stage benchmarks in the table above — no signup, runs in your browser.