How fast your customersleak away.
Churn is the most expensive number most businesses don't watch. A point of monthly churn quietly caps your list, your revenue, and the lifetime value everything is priced on. Enter your customers and how many left to get your churn rate, retention rate, and the lifespan that implies.
Your numbers
Active customers at the start of the period.
How many cancelled or lapsed during the period.
The verdict
Churn rate
5.0%
Retention rate
95.0%
Avg lifespan
20
Periods (months) a customer stays.
Cohort half-life
14
Periods to lose half.
Stayed vs left this period
Scenario · churn sets the lifespan
What each churn rate means for how long customers stay
Avg lifespan
20
months
Half-life
14
months to halve
Lifespan is roughly one divided by churn, so the relationship is brutal: at 5.0% monthly churn the average customer stays about 20.0 months. Halving churn roughly doubles lifespan — and LTV with it.
Sensitivity · the cost of churn
Lifespan & half-life by churn rate
| Monthly churn | Avg lifespan | Half-life |
|---|---|---|
| 1% | 100.0 mo | 69.0 mo |
| 2% | 50.0 mo | 34.3 mo |
| 3% | 33.3 mo | 22.8 mo |
| 5% | 20.0 mo | 13.5 mo |
| 7% | 14.3 mo | 9.6 mo |
| 10% | 10.0 mo | 6.6 mo |
Notice how non-linear it is: going from 10% to 5% churn does far more than going from 5% to 4%. The lowest churn rates buy disproportionately long customer lifespans.
Your move
Cut churn in half and you've doubled LTV. Let's find the leak.
5.0% churn, 95.0% retention — about 20.0-month average lifespan.
Most churn is decided in the first month, long before the cancel. Send me your funnel and onboarding and I'll show you where customers slip away — and the cheapest fix. Free, on a 30-minute call.
Plain English
The leak that sets your ceiling.
Churn rate is the share of customers who leave in a period — cancellations and lapses divided by the customers you started with. Retention is simply its mirror: everyone who stayed. They sound like soft, after-the-fact metrics, but they quietly govern the hardest numbers in the business, because a customer who churns takes all their future revenue with them.
The reason churn matters more than it looks is that it compounds. At a fixed acquisition rate, churn sets a hard ceiling your customer base converges toward — and it dictates average customer lifespan, which is one divided by your churn rate. Five percent monthly churn implies a 20-month average lifespan; ten percent halves it to ten. That lifespan is the multiplier under your entire LTV.
This calculator gives you the churn rate, the retention rate, the implied average lifespan, and the half-life — how long until a cohort shrinks to half its size. Together they turn 'we lose some customers' into a number you can actually manage against.
The formula
Churn rate = Customers lost ÷ Customers at start · Avg lifespan = 1 ÷ churn rate
Start with 1,000 customers, lose 50 in the month → 5% monthly churn, 95% retention. Average lifespan ≈ 1 ÷ 0.05 = 20 months, and a cohort halves in about 14 months.
Typical monthly churn by segment
What counts as 'high' churn depends heavily on your model — enterprise contracts churn an order of magnitude slower than consumer subscriptions. Rough monthly customer-churn benchmarks:
| Segment | Typical monthly churn |
|---|---|
| SaaS — SMB | 3–5% |
| SaaS — enterprise | 0.5–1% |
| B2C subscription | 5–9% |
| Media / streaming | 4–6% |
| E-commerce membership | 6–10% |
Source: Recurly / ChartMogul subscription churn benchmarks · 2025
Read your churn
Churn above your segment benchmark.
The leak is bigger than your peers'. Look at onboarding and the first 30–90 days — that's where most avoidable churn is decided, long before the cancel button.
Churn fine, growth still slow.
Acquisition, not retention, is the constraint. But protect the low churn — it's the cheaper of the two to keep than to win back.
Lifespan too short for your CAC.
If customers leave before they've repaid acquisition, the economics are upside down. Lift retention or cut CAC before scaling spend.
Churn spikes in a single month.
Usually a billing event, a price change, or a cohort issue — not a trend. Segment by cohort before reacting.
Plug the leak
01Nail the first 30 days
Most churn is decided in onboarding. A strong start — quick first value — is the highest-leverage retention work there is.
02Find the 'aha' fast
Get customers to the moment the product clicks before they lose interest; activation predicts retention.
03Watch for warning signs
Declining usage or logins flag churn weeks early. Reach out before the cancel, not after.
04Make leaving cost something
Accumulated value — data, history, integrations — raises switching cost and lowers churn honestly.
05Win back deliberately
A timed, specific win-back offer recovers a meaningful share of recent churners cheaply.
06Fix involuntary churn
Failed payments cause a surprising amount of churn. Dunning and card-update flows recover it quietly.
The vocabulary
- Churn rate
- Share of customers lost in a period — lost ÷ starting customers.
- Retention rate
- Share of customers who stayed — 100% minus churn rate.
- Customer lifespan
- Average time a customer stays — roughly 1 ÷ churn rate.
- Cohort half-life
- How long until a group of customers shrinks to half its original size.
- Involuntary churn
- Customers lost to failed payments, not a decision to leave.
Churn & retention questions
Divide the number of customers lost in a period by the number you had at the start, then multiply by 100. Losing 50 of 1,000 customers in a month is a 5% monthly churn rate.
Keep going
A calculator tells you what. A call tells you what to do about it.
Send me the account behind these numbers. I'll tell you straight where the money's leaking and what I'd fix first — free, and you keep it whether you hire me or not.