Blog · Finance metrics and formulas · SaaS
Customer lifetime value is the gross profit a customer brings over the whole relationship. This page gives the standard LTV formula, where each input comes from, a worked example on three segments with LTV against CAC, a discounted version, a method for B2B businesses without subscriptions, and the check that proves the segment figures.
The standard LTV calculation is average revenue per account per period, times gross margin percentage, divided by the churn rate for the same period. A customer paying $900 a month at a 75% gross margin, with 1.5% of customers leaving each month, has a lifetime value of 900 × 0.75 / 0.015 = $45,000. Customer lifetime value is gross profit, not revenue, and it is only useful next to what the customer cost to win.
LTV = ARPA × Gross margin % / Churn rate
Expected lifetime = 1 / Churn rate
ARPA is average revenue per account. All three inputs must be for the same period: monthly ARPA with monthly churn, or annual with annual. Dividing by churn is the same as multiplying the period's gross profit by the expected lifetime, so the formula reads as "gross profit per period × number of periods the customer stays."
David Skok's LTV and CAC formulas give the same structure, with the lifetime example "If the Monthly customer churn rate is 3%, then the Customer Lifetime will be 1/0.03 which is 33 months." In Excel, with ARPA in B2, gross margin in C2 and churn in D2:
=B2*C2/D2
Expected lifetime is =1/D2.
| Input | Source | How |
|---|---|---|
| ARPA | Billing export | Recurring revenue for the period / active accounts at the start of it |
| Gross margin % | P&L | (Revenue − cost of revenue) / revenue: hosting, support, onboarding, payment fees |
| Churn rate | Customer counts | Accounts lost in the period / accounts at the start of it |
Use customer churn, not revenue churn, in this form: it counts how many accounts leave, which is what sets the expected lifetime. The difference between churn, renewal and retention rates is set out in renewal rate, retention rate and churn rate, and churn has the one-line definition.
Monthly figures, in USD, for one SaaS company with 440 active accounts. LTV in G2 is =B2*C2/D2; lifetime in E2 is =1/D2.
| Segment | Accounts | ARPA (USD) | Gross margin | Monthly churn | Lifetime (months) | Gross profit per month (USD) | LTV (USD) |
|---|---|---|---|---|---|---|---|
| SMB | 300 | 400 | 70% | 3.0% | 33.3 | 280 | 9,333 |
| Mid-market | 120 | 900 | 75% | 1.5% | 66.7 | 675 | 45,000 |
| Enterprise | 20 | 3,500 | 80% | 0.8% | 125.0 | 2,800 | 350,000 |
Mid-market, step by step: 900 × 0.75 = 675 of gross profit a month. Divided by churn, 675 / 0.015 = 45,000. Expected lifetime is 1 / 0.015 = 66.7 months, and 675 × 66.7 = 45,000 again.
The enterprise lifetime of 125 months is more than ten years, longer than most contracts have existed. See the cap under "Where it goes wrong."
LTV means little until it is set against customer acquisition cost. With a CAC of 15,000 for a mid-market account and 4,000 for an SMB account:
| Segment | LTV (USD) | CAC (USD) | LTV : CAC |
|---|---|---|---|
| Mid-market | 45,000 | 15,000 | 3.0 |
| SMB | 9,333 | 4,000 | 2.3 |
Mid-market returns three times its acquisition cost; SMB 2.3 times. Skok's SaaS Metrics 2.0 puts the best SaaS businesses at "a LTV to CAC ratio that is higher than 3". That is a rule of thumb, and his definitions add that it assumes LTV without a gross margin adjustment and a gross margin of 80% or higher. On gross-profit LTV, as here, 3.0 is a stricter bar.
The simple formula treats a dollar in year five like a dollar today. The discounted form from Gupta and Lehmann's "Customers as assets" (Journal of Interactive Marketing, 2003) is:
Discounted LTV = Margin per period × Retention rate / (1 + Discount rate − Retention rate)
It assumes margin arrives at the end of each period, and only from customers still retained at that point. Use annual figures. For the mid-market segment:
| Input | Value |
|---|---|
| Annual margin (900 × 12 × 0.75, USD) | 8,100 |
| Annual retention | 85% |
| Discount rate | 10% |
| Multiple: 0.85 / (1.10 − 0.85) | 3.4 |
| Discounted LTV (USD) | 27,540 |
8,100 × 3.4 = 27,540. With a discount rate of zero the same formula gives 8,100 × 0.85 / 0.15 = 45,900, close to the simple 45,000; discounting at 10% takes off 40%. Monthly churn of 1.5% compounds to 83.4% annual retention, so 85% is slightly generous. In Excel, with margin in B2, retention in C2 and the discount rate in D2: =B2*C2/(1+D2-C2).
Distributors and manufacturers rarely have a churn rate: customers do not cancel, they stop ordering. Measure from purchase history instead:
LTV = Average annual gross profit per customer × Expected relationship years
A distributor whose customers bring an average of $18,000 of gross profit a year and keep buying for 6.5 years on average has an LTV of 18,000 × 6.5 = $117,000. Both inputs come from the sales ledger: gross profit by customer by year, and the span from first to last order for customers who have stopped. Customer lifetime value from the ledger works the method in full, including how to decide when a customer has stopped.
Two checks prove the segment figures.
LTV × accounts is plausible against total gross profit. Each segment's LTV times its accounts is the gross profit the current base is expected to deliver:
| Segment | Accounts | LTV (USD) | Accounts × LTV (USD) | Gross profit per month (USD) |
|---|---|---|---|---|
| SMB | 300 | 9,333 | 2,800,000 | 84,000 |
| Mid-market | 120 | 45,000 | 5,400,000 | 81,000 |
| Enterprise | 20 | 350,000 | 7,000,000 | 56,000 |
| Total | 440 | 15,200,000 | 221,000 |
15,200,000 is 68.8 months of today's gross profit of 221,000 a month. If your accounts have never stayed anywhere near that long on average, the churn input is too low.
Segment LTVs weighted by accounts give the blended figure. 15,200,000 / 440 = 34,545. Computing one LTV from blended inputs gives a different answer: blended gross profit per account is 221,000 / 440 = 502 and blended churn is 10.96 lost accounts / 440 = 2.49%, so 502 / 0.0249 = 20,164. The weighted figure is the one that adds back to the segments; the blended-input figure is not an average of anything.
=B2*C2*(1-(1-D2)^60)/D2, is 133,843 rather than 350,000.Covirage computes churn, retention and gross profit per customer and cohort from the uploaded billing and ledger files, then LTV by segment, with every input shown beside the result. Its deterministic tools do the arithmetic and the external AI model only explains it. See Covirage for SaaS sales teams to compute LTV by segment from your own billing export. To compare LTV with what it cost to win the customer, see the LTV to CAC ratio, and for the per-customer view around both, see unit economics.
The common form is average revenue per customer per period multiplied by gross margin percentage, divided by the churn rate for the same period. Dividing by churn is the same as multiplying by the expected lifetime, 1 / churn.
A common rule of thumb in subscription businesses is 3:1 or better, meaning a customer returns three times what it cost to win. Much higher can mean under-investment in growth. It is a convention, not a standard, and depends on payback time.
Gross profit. Revenue-based LTV ignores the cost of delivering the product or service, so it overstates what a customer is worth and makes acquisition spend look safer than it is.
Use purchase history. From the ledger, take each customer's average annual gross profit and the average number of years customers keep buying, then multiply. This suits B2B businesses without subscriptions, where churn is a gap in orders rather than a cancellation.