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Free tool
Plug in monthly retention rates from your cohort data. See the curve, half-life, average lifespan, and LTV multiplier. Compare against SaaS, ecommerce, and consumer subscription benchmarks.
Retention curve and key metrics
Retention curve
| Metric | Value | Benchmark |
|---|
How it works
Curve, half-life, lifespan. The three numbers every SaaS investor wants to see.
m1 = 70% m3 = 48% m6 = 42% m12 = 38%
Pull from your CRM or analytics. Cohort by signup month for cleanest data. Don't blend cohorts.
Smile shape good. Linear decline bad. Where the curve flattens tells you whether the product reached habit.
SaaS cohort, Q1
Multiply ARPU × gross margin × lifespan to get LTV. That's the number that justifies CAC, fundraising, and growth math.
Concepts explained
The retention curve is the most overloaded chart in SaaS. These six concepts keep the analysis honest.
Retention curve shape
Healthy SaaS curves drop sharply in months 1-3 then flatten. Curves that keep dropping linearly mean the product never reaches habit. Curves that flatten quickly mean you have a sticky core.
Half-life
How many months it takes for retention to drop to 50%. SMB SaaS half-life is 3-6 months. Mid-market is 12-18 months. Enterprise is 24+ months. A simple but revealing number.
Average lifespan
Sum of monthly retention rates approximates how many months the average customer stays. 70%+45%+30%+25%+...+5% ≈ 18 months lifespan. Drives LTV math.
LTV multiplier
If each customer pays $X/month at Y% gross margin, LTV = X × Y × lifespan. The retention curve is what determines lifespan. Better retention compounds dramatically.
Cohort vs blended
Blended retention ('we kept 90% last month') hides cohort-specific signals. New customers churn fastest, old ones rarely. Always look at cohort retention, not blended.
Why curves flatten
Customers who survive past month 3-6 are the ones who built habits. The curve flattens because the most likely-to-churn users have already churned. Late-month retention is dramatically higher.
Best practices
Cohort by signup month, not blended
Blended retention hides cohort-specific effects. Old cohorts pull blended numbers up. New cohorts pull them down. Always cohort.
Look for the flattening point
Where the curve flattens is where you reached product-market fit for that cohort. If it never flattens, customers never built habits.
Compare cohorts side by side
Newer cohorts should have flatter curves than older ones if your retention work is paying off. If cohorts look identical month after month, you have not improved.
Beware the survivor bias trap
A 24-month cohort retention number only includes customers who could possibly be retained 24 months. Year-old cohorts can't tell you about your two-year-old churners yet.
Tie retention back to acquisition channel
Channels that produce cheap-to-acquire customers often produce poorly-retaining customers. CAC and retention need to be analyzed together, not separately.
Built by the team behind SourceLoop
Guide
The drop in months 1-3 (how aggressively customers churn early), the flattening point (where the curve levels off, which is where you reached PMF for that cohort), and the flat-floor level (how high the curve plateaus, which is the ceiling on long-term retention). A healthy SaaS curve drops fast in months 1-3, flattens around month 6, and holds 30 to 50 percent long-term. A struggling curve declines linearly past month 12 because customers never form habits.
half_life = month at which retention = 50%
(interpolate between input months)
avg_lifespan ≈ sum(monthly_retention) for 0..N
(good approximation for typical curves)
ltv_multiplier = avg_lifespan
ltv = arpu * gross_margin * avg_lifespan The lifespan approximation gets less accurate as time horizons extend (you need to extrapolate the tail), but for 24-month cohorts it's accurate to within 5 percent. Long-tail customers (the ones who stayed 5+ years) drive enormous LTV that 24-month cohorts can't measure yet.
Month 1 retention is the most diagnostic single number in a SaaS retention curve. It tells you whether the user activated. Month 1 below 50% means most signups never get to the value moment. Improvements in onboarding, activation, and time-to- first-value all show up first as month 1 retention lifts. Improvements anywhere else (support, expansion, upsell) compound on whatever month 1 number you have.
If your Q3 cohort has higher month-3 retention than your Q1 cohort, your retention work is paying off. If they're identical, nothing changed. If Q3 is worse, something regressed (a product change, a CAC mix shift, a quality of traffic decline). Cohort-on-cohort comparison is the closest thing to a real-time signal you can get for retention work, and it's why teams that take retention seriously plot every new cohort against the previous one.
Lifespan in the LTV formula is the sum of retention. So a 5 percentage point lift in month-12 retention (from 35% to 40%) doesn't just add 5% to LTV — it adds 5% retained forever, plus 5% more month-13 customers who can churn or renew, plus 5% more month-14 customers, etc. Small retention improvements compound into very large LTV improvements when the time horizon is long. This is why investors look at NRR/GRR before any other SaaS metric.
Your cohort retains 70% in month 1, 55% in month 2, 48% in month 3, 42% in month 6, 40% in month 9, 38% in month 12, 35% in month 18, 32% in month 24. Sum across these ~26. Half-life is approximately 2.5 months (interpolating between m2 at 55% and m3 at 48%). Lifespan ~26 months. With $200/month ARPU and 80% gross margin, LTV = $200 × 0.80 × 26 = $4,160. Healthy mid-market SMB territory. Improve month-1 retention from 70 to 80 percent without changing later months and lifespan jumps to ~28 months, LTV to $4,480. A 14 percent point one improvement turned into 8 percent more LTV. Compound improvements is what retention work pays.
FAQ
Enter the percentage of customers retained at each milestone month (month 1, 2, 3, 6, 9, 12, 18, 24). The tool plots the retention curve, calculates half-life (months until 50%), estimated average lifespan (sum of monthly retention), and an LTV multiplier. It compares your curve against typical SaaS, ecommerce subscription, and consumer app benchmarks.
The classic 'smile' shape: steep drop in months 1-3, then a flattening curve that approaches a stable floor. The flatter the floor, the better the product-market fit. A linear decline that keeps dropping after month 6 means customers never form habits, which is hard to fix without product changes. A curve that flattens at 30%+ is healthy SaaS territory.
Self-serve consumer SaaS: 2 to 4 months. SMB SaaS: 3 to 6 months. Mid-market: 12 to 18 months. Enterprise B2B: 24+ months. Half-life is a quick proxy for product stickiness, but cohort analysis is more nuanced than a single number. A short half-life with a high stable floor is often better than a long half-life with continuous decline.
It's an approximation. If you keep 70% in month 1, 50% in month 2, 40% in month 3, etc., the expected number of months a random customer stays is approximately 0.7 + 0.5 + 0.4 + ... For an exact calculation you'd need integration of the retention curve, but the sum approximation is accurate to within 5% for typical curves and easier to compute. Some textbooks use 1/(1-retention) instead, which is equivalent for exponential curves but breaks for non-exponential ones.
Churn rate is a snapshot ('we lost 5% of customers last month'). Retention curve is the full story ('we lose 30% in month 1, 20% in month 2, then 5%/mo after'). The same blended churn rate can correspond to very different curve shapes, with very different LTV implications. Looking at the curve catches things blended churn hides.
Both. By signup month surfaces seasonal effects and product changes (Q1 cohort retains differently than Q3 cohort). By acquisition channel surfaces channel-quality effects (customers from Channel X retain better than Channel Y). Most teams start with signup month, then add channel as a second dimension once that's working.
Yes. No signup, no email gate. We host it because the same teams trying to improve cohort retention also need real attribution to know which acquisition channels deliver the customers that actually stick around, which is what SourceLoop does.
Capture and send full attribution data from every signup, lead, booking, and sale to your CRM and ad platforms, so you know exactly what's driving revenue.
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