What LTV is and why it matters more than ARPU
Lifetime Value is the total gross margin a customer generates over their entire life as a subscriber — not their ARPU, not their first payment, not the signed contract: what actually remains after subtracting cloud, support, and the rest of variable cost. High ARPU with high churn destroys value; modest ARPU with low churn builds a capitalizable machine. Series B funds in 2025 no longer buy isolated ARR — they buy a sustained LTV:CAC ratio with healthy NRR.
LTV formula (gross-margin adjusted version)
LTV = (Monthly ARPU × Gross margin %) ÷ Monthly churn rate
The version without gross margin that appears in old blogs (ARPU ÷ churn) inflates LTV 30-60% depending on the model — useful as a vanity metric, useless for decisions.
Example — Cairngorm SaaS, a field-service platform. Monthly ARPU 420 USD, gross margin 76% (includes hosting, L1 support, and integration maintenance), monthly churn 3.2% (logo churn). LTV = (420 × 0.76) ÷ 0.032 = 319.2 ÷ 0.032 = 9,975 USD. With a current CAC of 2,850 USD, the LTV:CAC ratio is 3.5x — right on the floor Bessemer requires to open a Series B conversation. CAC payback: 2,850 ÷ 319.2 = 8.9 months.
Logo churn vs revenue churn: the distinction that changes the story
- Logo churn. Percentage of customers that cancel in the period, whether they count for little or a lot.
- Gross revenue churn. Percentage of MRR lost to cancellations and downgrades, without counting expansion.
- Net revenue churn (equivalent to 100% − NRR). Percentage of MRR lost after subtracting expansion and upsell.
A SaaS can have 4.5% monthly logo churn and 1.8% revenue churn because the customers cancelling are the smallest — the big ones stay and expand. Measuring only logo churn in a business with long-tail ACV distribution hides the real story: the revenue is safe, the count is not. For LTV, use revenue churn when there are cohorts with expansion; use logo churn only if the ACV is homogeneous.
NRR: the metric that turned SaaS into a growth investment
Net Revenue Retention measures how much a cohort's MRR grows the following year without new customers. 110% NRR means a cohort came in at 1M USD MRR and, the following year, after net cancellations and expansions, stood at 1.1M. Series C SaaS companies with NRR above 130% (Snowflake, Datadog, MongoDB in their day) can tolerate very high CAC because the cohort pays for itself through expansion — the initial customer matters less than their 36-month trajectory.
Baseline 2025 table (Bessemer, OpenView, G Squared CFO Benchmarks):
| Stage | Median NRR | Top-quartile NRR | World-class NRR |
|---|---|---|---|
| Seed SMB | 95% | 105% | 115% |
| Series A mid-market | 102% | 115% | 125% |
| Series B enterprise | 108% | 120% | 135%+ |
| Post-IPO enterprise | 112% | 125% | 140%+ |
The 120% NRR threshold is the implicit filter for growth funds in 2025: below it, the business has to buy all its growth; above it, the installed base pays for it.
Cohorts: the angle the average hides
Aggregate LTV is a lying average. A Q1 cohort signed with dedicated onboarding can have 1.8% monthly churn and an 18,000 USD LTV; the Q3 cohort, signed during an aggressive outbound push, can have 5.4% churn and a 6,200 USD LTV. Blended LTV looks like 11,000 and describes neither reality. Analyzing cohorts month by month (or quarter by quarter) catches the channel or campaign poisoning the curve before the board sees it as an aggregate Q4 drop.
Causal vs voluntary churn: two different problems
- Voluntary churn. The customer decides not to renew: they didn't get value, found an alternative, changed their stack. Reduced with product, customer success, and pricing.
- Involuntary churn. Expired card, failed payment, credit limit. In SMB SaaS it accounts for 20-40% of total churn. Reduced with automated dunning (Stripe Billing, Recurly), smart retry policies, and pre-renewal reminders. It's the highest-ROI lever almost nobody optimizes.
Recovering 25% of involuntary churn in a SaaS with 4% monthly churn moves effective churn to 3.2%, which raises LTV by 25%. One week of product work that moves more than six months of growth campaigns.
Contrarian: cutting churn 1 point weighs more than doubling traffic
The typical founder's intuition is that growing requires more traffic, more ads, more SDRs. The arithmetic says otherwise. A SaaS with 5% monthly churn and 6,000 USD LTV that cuts churn to 4% gets to a 7,500 USD LTV — 25% more value per customer without touching acquisition. To achieve the same effect via CAC, you'd have to cut acquisition cost 25%, which in saturated 2025 paid-ad markets is nearly impossible. Investing in customer success, onboarding, and retention-focused product returns more per dollar than almost any growth channel beyond a certain maturity threshold. Practical post-product-market-fit rule: if monthly churn exceeds 3.5% in SMB or 1.5% in mid-market, prioritize retention over acquisition.
Mistakes that silently destroy LTV
- Calculating LTV on gross ARPU. Without adjusting for gross margin, LTV inflates 30-50%. The correct formula multiplies by gross margin before dividing by churn.
- Using annualized churn instead of monthly. 30% annual is not 2.5% monthly: it is ~2.9% monthly compounded. The error compounds in 24-36 month forecasts.
- Mixing logo churn with revenue churn in the same dashboard. They are different metrics with different decisions. Segment them.
- Ignoring involuntary churn. Expired cards and failed payments are churn that requires no commercial work to recover — it is pure product.
- Comparing LTV without adjusting for cohort or segment. Blended LTV hides that the self-serve segment pays, enterprise expands, and SMB bleeds.
When to use this simulator and when not
Use it when you have at least 6 months of audited churn history and stable ARPU. Use it monthly for unit-economics dashboarding and before every major pricing decision. Don't use it in the first 60 days post-launch (early-cohort churn predicts nothing), nor in businesses with fewer than 100 active customers (variance beats signal). It doesn't replace a retained cohort analysis — this simulator gives the photo, cohort analysis gives the film.
Cross-link: the full unit-economics view
Pair it with [Churn rate by industry](/simulador/saas/churn-rate) to see where your number sits against the market; [CAC Payback and Magic Number](/simulador/marketing/cac-payback) to close the efficiency equation; [CAC vs LTV](/simulador/saas/cac-vs-ltv) for the aggregate ratio; [MRR Projection](/simulador/saas/mrr-proyeccion) for the 12-24 month forecast; and [Subscription Pricing](/simulador/saas/pricing-suscripcion) when LTV is fixed via packaging, not retention.
LTV:CAC ratio interpretation
The ratio is not a single threshold — it reads differently depending on the stage and growth posture of the business:
- Below 2x: The company destroys value on every new acquisition. Either CAC is too high, churn is too severe, or ARPU is insufficient for the cost structure. Fundraising at this ratio in 2026 requires exceptional growth velocity as compensation.
- 2x-3x: Survival zone. Viable but fragile. One quarter of elevated churn or inflated S&M pushes it below break-even.
- 3x-5x (healthy): The standard Series B target per Bessemer, Battery Ventures, and OpenView. The company is investing efficiently and has room to increase S&M spend.
- Above 5x (growth-starved): You are leaving revenue on the table. The unit economics justify higher S&M investment. Common in bootstrapped or capital-constrained businesses that grew without aggressive demand generation.
- Above 8x: Often signals under-investment. Snowflake and Datadog operated above 8x pre-IPO but with deliberate capital efficiency strategies; for most SaaS, an 8x+ ratio is a prompt to accelerate, not to celebrate.
When to fix churn vs when to reduce CAC
The diagnostic rule: if LTV:CAC is below 3x because LTV is low (churn is the dominant variable), fix retention first — reducing monthly churn 1pp grows LTV faster than cutting CAC 20%. If LTV:CAC is below 3x because CAC is high (LTV looks adequate but acquisition is expensive), optimize channel mix before touching the product. Calculate: LTV ÷ (3 × target LTV:CAC) = maximum sustainable CAC. If your current CAC exceeds that ceiling, the channel reallocation is not optional.