Customer Lifetime Value Analysis SOP

A customer lifetime value analysis tells you how much gross profit an average customer brings in before they leave, and how much you can afford to spend to win the next one. Plan for a week of data work, then a one-hour refresh every month. Most early LTV figures are fiction: they use revenue instead of margin, an average churn from one good month and a lifetime that runs for decades. This SOP builds an LTV figure you can defend in front of an investor and use to set acquisition budgets.

What is customer lifetime value analysis and when should you use it?

Customer lifetime value (LTV, sometimes CLV) is the total gross margin a customer generates over their relationship with you. For subscriptions the standard formula is average monthly revenue per account × gross margin % ÷ monthly churn rate, the version David Skok uses in his SaaS metrics guide. For repeat-purchase businesses it is average order value × orders per year × years retained × gross margin %.

Use this SOP:

• Once you have 3 or more months of payment data, so churn comes from behaviour instead of hope.
• Before you set a ceiling on acquisition cost, since LTV decides how much a customer is worth winning.
• When you sell to more than one segment or plan, because a blended LTV hides your best and worst customers.
• Before fundraising, where LTV:CAC is one of the first ratios investors check.

Retention curves are the input here. Building and reading them is the job of the customer retention analysis SOP; this page turns them into money.

What do you need before you start?

• A payment export from Stripe, Shopify or your billing tool with customer ID, date and amount for every charge.
• Your gross margin %, from the unit economics validation SOP.
• A segment label per customer: plan, customer type, channel or country.
• CAC per segment or channel, from your acquisition tests.
• ChartMogul or Baremetrics if you want cohort charts without building them by hand.

How do you run it, step by step?

1. Pick the formula that matches how customers pay

Subscriptions use the churn formula. Repeat-purchase businesses use the order formula. Usage-based models use average monthly gross margin per customer and the same churn logic. Write the formula at the top of your sheet, so everyone reading it knows what the number means.

2. Build monthly cohorts

Group customers by the month they first paid and track revenue from each group in every following month. A cohort table shows whether newer customers stay longer or shorter than early ones. If newer cohorts churn faster than your early adopters, a blended average flatters the future and your LTV has to follow the newer curve.

3. Calculate churn from the cohorts

Use the average monthly churn across cohorts that are at least 3 months old, excluding month 1 if trial cancellations spike there and treating that month separately. Track revenue churn too: upgrades and expansion can offset lost customers, which makes net revenue retention a second lens.

4. Use gross margin, not revenue

Multiply monthly revenue per customer by your gross margin percentage. LTV built on revenue overstates value by the full cost of serving the customer, and a 60% margin business that quotes revenue LTV inflates it by two thirds.

5. Cap the lifetime

The churn formula assumes customers can stay forever. Cap the horizon at 36 months while your company is young, using expected months in 36 = (1 − (1 − churn)^36) ÷ churn. Data older than your company does not exist, so claiming a 7-year lifetime from 8 months of history is a guess.

6. Split by segment

Calculate LTV for each plan, customer type and acquisition channel with at least 30 customers. Segments with 3 times the LTV of others change who you target. Segments below 30 customers get reported with a warning label.

7. Compare with CAC and set budgets

Divide each segment's capped LTV by its CAC. Skok's widely quoted benchmark is LTV at least 3 times CAC. Set the maximum CAC you accept per segment at one third of its capped LTV and use that number in every acquisition test.

Template you can copy

LTV ANALYSIS SHEET (one block per segment)

Segment: ______________   Customers in segment: ____
Formula used: subscription / repeat purchase / usage

Average monthly revenue per account (ARPA)  $____
Gross margin %                              ____%
Monthly gross margin per customer           = ARPA x gross margin %       $____
Monthly churn (cohorts 3+ months old)       ____%
Uncapped lifetime (months)                  = 1 / churn                   ____
Uncapped LTV                                = monthly margin / churn      $____
Expected months within 36                   = (1 - (1 - churn)^36) / churn ____
Capped LTV (36 months)                      = monthly margin x expected months $____
CAC for this segment                        $____
LTV:CAC (capped)                            ____
Maximum CAC to accept                       = capped LTV / 3              $____

COHORT TABLE
First-pay month | Customers | Revenue M1 | M2 | M3 | M4 | M5 | M6 | ... | % retained M6

Worked example: a scheduling tool for clinics and salons

This is an illustrative case with invented numbers. A founder sells appointment software to two segments, both at an 80% gross margin.

On the uncapped numbers clinics look like the star at 4.8 times CAC, and the founder planned to hire a salesperson for them. The capped figure drops clinics just below the 3:1 line, because their low churn only pays off in years four and beyond, which she has no data for. Salons look smaller per customer and win on the ratio, thanks to a cheap Instagram channel. She keeps clinics on a lower-cost demo process and puts the new budget into salons, with a maximum CAC of $139 per salon.

What should you measure, and when do you stop?

The first analysis stops when every segment with 30 or more customers has a capped LTV and a CAC ceiling. After that, refresh monthly and stop trusting the figure if newer cohorts churn noticeably faster than the ones you based it on.

Which mistakes should you avoid?

• Using revenue instead of gross margin. Your LTV then includes money you pay to suppliers and servers.
• Taking churn from your best month. Use the average across mature cohorts.
• Running the lifetime to infinity. Cap it at 36 months until you have the history to justify more.
• Blending all customers into one number. Segments with different churn need different acquisition budgets.
• Calculating LTV from 4 weeks of data. Below 3 months, label the figure an assumption.

How can AI speed this up?

Upload a payment export to an AI assistant and ask it to build the cohort table, calculate churn per cohort and fill in the template for each segment. It can also spot customers who downgraded before cancelling, a pattern that points to fixable churn. Check one cohort by hand before you trust the rest, since AI tools sometimes count refunds or failed payments as active revenue.

The F/MS AI co-founder walks through these calculations with you and checks whether the assumptions hold together.

Where does this SOP fit in your validation plan?

LTV analysis comes after you have retention data and before you scale acquisition.

1. Build the retention curves first with the customer retention analysis SOP.
2. Pair each segment's LTV with real acquisition costs from the customer acquisition cost validation SOP.
3. Check margin per unit in the unit economics validation SOP.
4. Raise ARPA through the pricing sensitivity testing SOP if LTV falls short.
5. Use capped LTV in your financial model validation.

See all Business Model Validation SOPs. When it is time to show the numbers to investors, the F/MS pitch deck tool has a slide structure for LTV, CAC and payback.

FAQ

How do you calculate customer lifetime value?

For subscriptions: average monthly revenue per account × gross margin % ÷ monthly churn rate. Cap the result at 36 months for a young company.

What is a good LTV to CAC ratio?

3:1 or higher is the widely quoted benchmark from David Skok. Far above 5:1 can mean you underinvest in growth.

How much data do I need to calculate LTV?

At least 3 months of payments and 30 customers per segment. Below that, treat LTV as an assumption and update it monthly.

Should LTV use revenue or profit?

Gross margin. Revenue-based LTV ignores what it costs to serve the customer and overstates what you can spend on acquisition.