Definition
Last reviewed June 7, 2026
The LTV formula assumes a constant churn rate, which is rarely true in practice. Cohort analysis tells you the real picture: month-12 retention, month-24 retention, the shape of the retention curve. A back-loaded retention curve (where churn happens late) gives you a much higher real LTV than the formula suggests. A front-loaded curve (where churn happens early) gives you a lower one.
LTV-to-CAC is the headline ratio: greater than 3 to 1 is the standard benchmark for a healthy subscription business. Under 2 to 1 says you are spending too much to acquire the revenue you keep. Over 5 to 1 sometimes says you are under-investing in growth and could spend more to acquire more profitably. The ratio sits next to CAC payback as the two numbers any operator should track.
INSIDEA's pattern with customers is to compute LTV three ways: the simple formula for the board, the cohort-based real number for the operating team, and the segmented version (by ICP, by acquisition channel) for budget decisions. The board number tells the story. The cohort number tells the truth. The segmented number tells you where to put the next dollar of acquisition spend.
FAQs
The simplest formula is (average revenue per customer × gross margin %) ÷ customer churn rate. For example, $100 monthly average revenue × 80% gross margin ÷ 2% monthly churn = $4,000 LTV. The formula assumes constant churn, which is rarely true; cohort retention is more accurate.
Greater than 3 to 1 is the standard benchmark for a healthy subscription business. Under 2 to 1 says you are spending too much to acquire the revenue you keep. Over 5 to 1 sometimes says you are under-investing in growth and could spend more to acquire more profitably.
The standard formula assumes churn is constant, which is rarely true. Cohort retention shows the actual shape of the retention curve: month-12 retention, month-24, the steepness of the early drop. A back-loaded curve gives you higher real LTV than the formula. A front-loaded curve gives you lower. The shape matters.
Three ways. The simple formula for the board. Cohort retention for the operating team. Segmented LTV by ICP and acquisition channel for budget decisions. The board number tells the story. The cohort number tells the truth. The segmented number tells you where to put the next dollar of acquisition spend.
Related terms
Customer Acquisition Cost (CAC) is the total sales and marketing spend required to win a new customer, divided by the number of new customers acquired in the period. It is the cleanest single measure of acquisition efficiency: are you spending more or less than the next dollar of customer revenue is worth.
Annual Recurring Revenue (ARR) is the normalized annualized revenue a subscription business expects from its active contracts. It is calculated by taking MRR × 12 or by summing each subscription's annualized fee. ARR is the headline number SaaS investors and operators track because it represents the durable, predictable revenue base of the business stripped of one-off variability.
Monthly Recurring Revenue (MRR) is the predictable, normalised revenue a SaaS business expects each month from its subscription customers. It is calculated by summing each active subscription's monthly fee, with annual contracts divided by 12. MRR is the single most important metric in subscription-software finance because it predicts ARR, growth rate, and runway without requiring the volatility of one-off bookings to interpret.
Net Revenue Retention (NRR) measures how much revenue a SaaS business retains from a cohort of customers over a period, including expansion, contraction, and churn. NRR is calculated as: (Starting ARR + Expansion - Contraction - Churn) ÷ Starting ARR. NRR over 100% means the cohort grew without new logos. Public SaaS leaders run 110-130% NRR and it is one of the strongest predictors of long-term value.
Churn Rate is the percentage of customers (or revenue) lost over a period, expressed monthly or annually. Logo Churn measures customers lost. Revenue Churn measures ARR lost. Both matter, and they often tell different stories: a business can have low logo churn but high revenue churn if it loses one big customer, or the opposite if it loses many small ones.
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