How many customers — and how much revenue — you are losing each period. Customer churn and retention for a month, quarter or year, the annualised equivalent, the average customer lifetime that churn implies, and gross and net revenue churn from MRR. Everything updates live in your browser; the defaults are the worked example.
The maths: churn rate = customers lost ÷ customers at start × 100. Retention is the mirror: 100 − churn. Average customer lifetime = 1 ÷ churn rate (as a fraction), in periods.
Annualised churn compounds the period rate: 1 − (1 − monthly rate)12. It is what a steady period rate adds up to over a year — not simply the rate × 12.
The maths: gross revenue churn = (churned + contraction) ÷ starting MRR × 100. Net revenue churn subtracts expansion first: (churned + contraction − expansion) ÷ starting MRR × 100.
Revenue churn can differ sharply from customer churn: losing a few large accounts hurts revenue more than losing many small ones, which is why both rates are worth tracking side by side.
Customer churn and retention by period with an annualised equivalent and implied lifetime, plus gross and net revenue churn from MRR.
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Calculate customer churn rate and retention for a month, quarter or year, see the annualised equivalent and the average customer lifetime that churn implies, then work out gross and net revenue churn from starting MRR, churned and contracted MRR, and expansion.
A SaaS starts the month with 1,200 customers and loses 48: churn is 48 ÷ 1,200 = 4.0%, retention is 96%, and the implied average customer lifetime is 1 ÷ 0.04 = 25 months. Compounded over a year, 4% monthly churn becomes 1 − 0.96^12 = 38.73% annualised. On the revenue side it starts at $95,000 MRR, loses $3,800 to churn and $1,200 to contraction — gross revenue churn of $5,000 ÷ $95,000 = 5.26% — but expansion adds $7,000, so net revenue churn is ($5,000 − $7,000) ÷ $95,000 = −2.11%: net negative churn, a net revenue retention of 102.11%.
Customer churn rate = customers lost in the period ÷ customers at the start of the period × 100; customers gained during the period are excluded, so a fast-growing company cannot hide churn behind new sales. Retention rate = 100 − churn rate. The annualised equivalent compounds the period rate — 1 − (1 − rate)^12 for monthly, ^4 for quarterly — because each period’s losses shrink the base the next period’s rate applies to. Implied average lifetime = 1 ÷ churn rate as a fraction, in periods. Gross revenue churn = (churned MRR + contraction MRR) ÷ starting MRR × 100; net revenue churn subtracts expansion MRR from the losses first, and net revenue retention = 100 − net revenue churn. A zero starting base shows a dash instead of dividing by zero.
It depends on who you sell to: consumer subscriptions often churn several percent a month, small-business SaaS commonly runs 3–7% monthly, and enterprise SaaS can be under 1% monthly because contracts are annual. Judge your rate against your segment and your own trend — and watch revenue churn alongside it, since keeping large accounts matters more than the raw count.
It is what happens when expansion revenue from existing customers — upgrades, extra seats, add-ons — exceeds everything lost to cancellations and downgrades, so net revenue churn drops below zero. The existing base grows revenue on its own, giving net revenue retention above 100%, the pattern behind the fastest-compounding SaaS companies.
They are two sides of the same period: retention is the share of starting customers (or revenue) still there at the end, and churn is the share that left, so the two always add to 100%. Report whichever your audience expects, but never mix a customer retention figure with a revenue churn figure in the same comparison.
Because churn compounds on a shrinking base. Losing 4% of 1,200 customers leaves 1,152; the next month’s 4% applies to 1,152, not 1,200. Over twelve months that gives 1 − 0.96^12 ≈ 38.73%, noticeably less than the naive 48% — and the gap grows with the rate.
No. Churn is measured only against the customers you started the period with. Netting new sign-ups against losses produces a net growth figure, not a churn rate, and it can disguise a serious retention problem behind strong sales.
Average lifetime is 1 ÷ churn rate, so at 0% churn it would be infinite — the calculator shows a dash instead. The same applies when the starting customer count or starting MRR is zero: the rate has no base, so a dash is shown rather than a division by zero.
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