LTV is the single most over-claimed and under-measured number in small business. Optimistic LTV justifies overspending on acquisition; realistic LTV gives you a reliable budget. This guide covers the formulas by business model, the cohort approach that produces defensible numbers, and the levers that genuinely grow LTV.
The Formulas by Business Model
| Model | LTV formula | Inputs you need |
|---|---|---|
| Subscription / SaaS | (ARPU × Gross Margin) ÷ Monthly Churn | ARPU, gross margin, churn rate |
| Ecommerce (DTC, retail) | AOV × Gross Margin × Repeat Purchases | AOV, gross margin, lifetime orders |
| Marketplace | GMV × Take Rate × Margin × Purchase Frequency × Tenure | Track buyer and seller separately |
| Services / Agency | Avg engagement value × Gross Margin × Renewals | Engagement size, margin, renewal rate |
| Hardware / one-time | Order Gross Profit + Accessory + Service Attach | Initial profit + recurring attach |
Gross Profit, Not Revenue
Always compute LTV on contribution margin or gross profit. A customer paying $100/month at 30% gross margin contributes $30/month — and that's what should accumulate into LTV. Using revenue inflates the number by 3x in this case and leads to overspending on acquisition.
The Cohort Approach
The most reliable LTV comes from tracking actual cohorts over time. Group customers by their acquisition month, then track cumulative gross profit per customer for that cohort each subsequent month. After 12-24 months, the curve flattens and you have empirical LTV — no extrapolation required.
For young businesses without long-running cohorts, take the most mature cohort you have, fit a simple decay curve, and use the asymptote as your conservative LTV estimate. Anything more aggressive is wishful thinking.
The Levers That Move LTV
- Reduce churn. For subscriptions, a 1 percentage-point reduction in monthly churn (5% → 4%) raises LTV by ~25%. Often the highest-ROI work in the business.
- Raise ARPU. Pricing increases, premium tiers, value-add features. A 10% price increase with no churn impact is a 10% LTV increase, full stop.
- Cross-sell and upsell. Each additional product per customer multiplies LTV linearly with attach rate.
- Improve gross margin. Lower COGS, lower support cost per customer, lower processing. Every gross-margin point flows straight to LTV.
- Extend tenure. Lifecycle programs, loyalty tiers, customer success investment. Especially impactful in industries with annual or biennial renewal cycles.
LTV Mistakes to Avoid
- Using revenue instead of gross profit.
- Extrapolating from young cohorts that haven't yet seen real churn.
- Treating "lifetime" as forever rather than discounting to a finite horizon.
- Mixing customer segments with very different retention behaviour into a single LTV number.
- Not refreshing LTV when pricing, product, or onboarding changes.
Try It Yourself
Model contribution margin and payback with the BizKit profit-margin and ROI tools.
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