How to Calculate Your LTV

• Step 1: Calculate Average Revenue per Account (ARPA)
  • When to segment ARPA
• Step 2: Calculate Gross Margin
  • The customer success allocation question
• Step 3: Calculate Monthly Churn Rate
  • Customer churn vs revenue churn
• Step 4: Plug Into the LTV Formula
  • Verifying the LTV math
• Step 5: Adjust for Expansion (Net Revenue Retention)
  • Caveat: expansion outpacing churn
• Step 6: Use LTV in Real Decisions
• Common LTV Mistakes
• When to Recalculate LTV
• LTV by Cohort
• The LTV Decision Framework
• Next Steps

Customer Lifetime Value (LTV) is the total gross profit a customer generates from acquisition until they churn. It is the denominator of the LTV:CAC ratio, the multiplier in every valuation model, and the single number that justifies how much you can afford to spend on acquisition. Getting LTV wrong leads to either underspending on growth (when LTV is overestimated and CAC looks too high) or burning through cash on acquisition (when LTV is underestimated and you over-invest).

The short answer:

LTV = ARPA × Gross Margin / Monthly Churn Rate

A customer paying $200/month at 80% gross margin and 2% monthly churn has an LTV of $8,000. This guide walks through the calculation step by step, plus three variations for different business models, then covers the most common mistakes and when to recalculate.

Step 1: Calculate Average Revenue per Account (ARPA)

ARPA is your monthly subscription revenue divided by your customer count. Use only recurring revenue — exclude one-time fees, setup charges, and professional services.

Monthly ARPA = MRR / Total active customers

Example:

• Total MRR: $480,000
• Active customers: 1,200
• ARPA: $400/month

For SaaS with annual contracts, divide annual contract value by 12 to get monthly ARPA. A $4,800/year contract is $400/month ARPA.

When to segment ARPA

For mixed customer bases (SMB + mid-market + enterprise), calculate ARPA by segment. A blended ARPA hides important detail. SMB might be $80/month, enterprise might be $2,500/month — averaging them produces a number that describes no actual customer. The blended ARPA can shift dramatically as your customer mix shifts, even if individual segment ARPA is stable, leading to misleading LTV trends.

If you serve two or more distinct segments, calculate and track LTV separately for each. This is more work but produces more useful answers than a single blended number.

Step 2: Calculate Gross Margin

Gross margin is the percentage of revenue left after direct costs of serving customers:

Gross Margin = (Revenue − COGS) / Revenue

For SaaS, COGS typically includes:

• Hosting and infrastructure (AWS, GCP, etc.)
• Payment processing fees (Stripe ~2.9%)
• Third-party API costs that scale per customer
• Customer support team costs

It does not include sales, marketing, R&D, or G&A.

Example:

• Revenue: $480,000
• Hosting: $48,000
• Payment processing: $14,000
• Support team: $22,000
• COGS: $84,000
• Gross profit: $396,000
• Gross margin: 82.5%

Healthy SaaS gross margins run 75-85%. Below 70% often signals services-heavy or infrastructure-heavy economics that limit valuation. Above 85% is achievable for self-serve SMB SaaS with minimal support burden.

The customer success allocation question

Customer success (CS) costs are an edge case. Strict GAAP would put CS team costs into operating expense, not COGS. But operationally, many CS hours go into retention work — keeping customers from churning — which directly affects LTV. Different SaaS finance teams handle this differently. A common middle ground: include the "tier 1 reactive support" portion of CS in COGS, but exclude the "strategic CS / account management" portion. Document whichever choice you make and apply it consistently.

Step 3: Calculate Monthly Churn Rate

Monthly customer churn is the percentage of customers lost each month:

Monthly Churn = Customers Lost / Customers at Start of Month

Example: 1,200 customers at start of month, 24 churned during month:

• Monthly churn = 24 / 1,200 = 2.0%

Customer churn vs revenue churn

You can churn customers slowly but revenue quickly if the customers leaving are high-ARPA ones. Always calculate both:

• Customer churn: for SMB-focused SaaS where ARPA is roughly uniform
• Revenue churn: for enterprise-heavy SaaS where losing one big customer dwarfs many small ones

Use the Churn Rate Calculator to compute both and stress-test against benchmark ranges.

For most SaaS, use revenue churn for LTV math when ARPA varies meaningfully across customers. The formula stays the same; you just replace customer counts with revenue dollars in the churn calculation.

Step 4: Plug Into the LTV Formula

With ARPA, gross margin, and monthly churn in hand:

LTV = ARPA × Gross Margin / Monthly Churn

Using our example numbers:

• LTV = $400 × 0.825 / 0.02
• LTV = $330 / 0.02
• LTV = $16,500

This number tells you that each customer, on average, is worth $16,500 in gross profit over their lifetime with you.

Verifying the LTV math

A useful gut-check: the formula above implies an average customer lifetime of 1 / monthly churn months. At 2% monthly churn, that's 50 months (just over 4 years). Multiplied by monthly gross profit per customer ($400 × 82.5% = $330), you get $330 × 50 = $16,500. The formula is a closed-form solution to the same arithmetic.

If your churn data suggests average customer lifetime is wildly different from 1 / monthly churn, your churn calculation is probably off. The formula assumes constant churn rate — if churn is higher in early months and lower in later months (which is typical), the true lifetime can be longer than the formula suggests.

Step 5: Adjust for Expansion (Net Revenue Retention)

The basic LTV formula assumes flat revenue per customer over time. For SaaS with meaningful expansion (upgrades, additional seats, usage growth), this understates LTV. Adjusted formula:

LTV (with expansion) = ARPA × Gross Margin / (Monthly Churn − Monthly Expansion Rate)

Where monthly expansion rate is your monthly NRR uplift on existing customers.

Example with expansion:

• Monthly churn: 2%
• Monthly expansion: 1% (from upgrades and added seats)
• Net retention rate: −1% (net loss of 1% per month after expansion)
• LTV = $400 × 0.825 / 0.01 = $33,000

That single percentage point of monthly expansion doubled LTV. This is why investors obsess over Net Revenue Retention and why expansion playbooks are the highest-leverage retention investment.

A 1% improvement in monthly expansion typically has more impact on LTV than a 1% reduction in churn — because expansion compounds across your entire customer base, not just the lost cohort.

Caveat: expansion outpacing churn

If your monthly expansion exceeds monthly churn (net negative churn), the formula above produces a negative or undefined LTV — mathematically infinite. This is unrealistic in practice; expansion eventually plateaus as customers reach their natural usage ceiling. Many sophisticated SaaS finance teams cap the implied lifetime at 60 months (5 years) for net-negative-churn cohorts to produce a realistic LTV.

Step 6: Use LTV in Real Decisions

LTV by itself is informational. Paired with CAC, it becomes actionable:

Use the LTV:CAC Ratio Calculator to model how your LTV connects to acquisition decisions.

Common LTV Mistakes

Five errors that consistently produce broken numbers:

1. Using annual churn instead of monthly. The math doesn't translate directly because churn compounds. Convert: monthly churn = 1 − (1 − annual churn)^(1/12).
2. Forgetting gross margin. Multiplying revenue by retention without applying gross margin overstates LTV by 15-25%.
3. Using stale churn data. Cohort churn from 12+ months ago doesn't reflect current product or pricing.
4. Confusing one-off revenue with recurring. Setup fees and services don't recur. Exclude them from ARPA.
5. Reporting LTV "for paying customers only" excluding trials. This isn't wrong, but be explicit. Trial-to-paid conversion belongs in the CAC numerator, not the LTV adjustment.

When to Recalculate LTV

LTV is a slow-moving number, but the inputs shift:

• After every pricing change (recalculate within 90 days)
• After major product changes that affect churn
• At the start of every annual budget cycle
• Before every fundraise or strategic transaction
• Quarterly as a hygiene check

If your LTV has not been recalculated in 6+ months, the number you're using is probably wrong. Most material LTV shifts come from churn changes (pricing changes that increase price-driven churn, product changes that affect retention) rather than ARPA or gross margin shifts.

LTV by Cohort

Blended LTV can mask important detail. Cohort-level LTV — calculated separately for customers acquired in each quarter — reveals whether unit economics are improving or deteriorating over time.

A healthy SaaS company shows:

• Newer cohorts with similar or higher LTV than older cohorts
• Stable or improving cohort gross margins
• Declining cohort churn rates (as onboarding and product mature)

A declining cohort LTV trend is a leading indicator that your business model is breaking down. Catching it early (cohort analysis quarterly) lets you respond before the headline blended LTV deteriorates 6-9 months later.

The LTV Decision Framework

Once you have LTV calculated, three operational uses:

1. Maximum acceptable CAC: LTV / 3 is the rough ceiling for paid acquisition spend.
2. Channel investment decisions: Channels producing customers with high LTV deserve disproportionate investment, even at higher CAC.
3. Segment focus: Segments with materially higher LTV should be prioritized in product roadmap and marketing positioning.

These three uses turn a static LTV number into recurring operational impact. Without them, LTV is just a metric on a quarterly report.

Next Steps

Pull your ARPA, gross margin, and monthly churn numbers today and run the math.

• Use the LTV Calculator for a fast LTV estimate plus scenario analysis.
• Verify your churn rate with the Churn Rate Calculator — both customer and revenue churn.
• Combine LTV with CAC using the LTV:CAC Ratio Calculator to translate the number into a real acquisition spending decision.