Customer Lifetime Value (CLTV) Calculator
Calculate the true lifetime value of your average customer from ARR, gross margin, and churn — then use that number to set a defensible ceiling on retention and expansion spend.
What's inside
- Core CLTV formula: ARR × Gross Margin % ÷ Churn Rate
- Multi-year discounted CLTV formula for long-contract businesses
- CAC:CLTV benchmark ratio table (1:1 danger zone to 8:1+ under-investing)
- CAC payback period formula with worked example
- Maximum justified retention-spend formula per at-risk account
- Segment-level CLTV comparison worksheet (fill-in)
- Churn-rate sensitivity table showing CLTV swing from 5% to 30% churn
- Guidance on turning the output into a retention-budget business case
The core formula
`` CLTV = (Average Annual Recurring Revenue per Customer × Gross Margin %) ÷ Annual Churn Rate ``
Where:
- ARR per customer = total recurring revenue ÷ number of active customers
- Gross Margin % = (Revenue − COGS) ÷ Revenue — use cost of hosting, support, and delivery, not blended company margin
- Annual Churn Rate = customers lost in the last 12 months ÷ customers at the start of the period, as a decimal (12% = 0.12)
Worked example
| Input | Value |
|---|---|
| Average ARR per customer | $24,000 |
| Gross margin | 78% |
| Annual churn rate | 15% |
`` CLTV = ($24,000 × 0.78) ÷ 0.15 CLTV = $18,720 ÷ 0.15 CLTV = $124,800 ``
This customer is worth $124,800 in gross-margin dollars over their full lifetime — not $24,000 (one year of ARR) and not infinite.
Step 2 — Discount it if you sell multi-year contracts
A dollar next year is worth less than a dollar today. Add a discount rate (use your cost of capital, or a standard 10%):
`` Discounted CLTV = CLTV ÷ (1 + discount rate) ^ average contract length in years ``
Example: same customer, 10% discount rate, 3-year average tenure: `` $124,800 ÷ (1.10)^3 = $124,800 ÷ 1.331 = $93,764 ``
Use the discounted number when comparing CLTV against a payback period or building a board-facing case — it's the more defensible figure.
Step 3 — Turn CLTV into a spending ceiling
`` Maximum justified CAC = CLTV ÷ target CLTV:CAC ratio Maximum justified retention/save spend per at-risk account = (CLTV × probability the spend prevents churn) − cost of the spend ``
Benchmark CLTV : CAC ratios
| Ratio | Read |
|---|---|
| Below 1:1 | You lose money on every customer you acquire. Stop growth spend, fix retention first. |
| 1:1 – 3:1 | Underwater or barely break-even once overhead is counted. |
| 3:1 | Minimum viable — the widely used SaaS floor. |
| 5:1 and above | Healthy. Likely room to spend MORE on acquisition or retention. |
| Above 8:1 | You may be under-investing — a sign to increase spend, not a badge of honor. |
Step 4 — Payback period
`` CAC Payback (months) = CAC ÷ (Average Monthly Recurring Revenue per customer × Gross Margin %) ``
Example: CAC of $6,000, MRR per customer of $2,000, 78% margin: `` $6,000 ÷ ($2,000 × 0.78) = $6,000 ÷ $1,560 = 3.8 months ``
Under 12 months is generally healthy for SMB/mid-market SaaS; under 18–24 months is acceptable for enterprise.
Fill-in worksheet — run per segment, not just company-wide
Blended CLTV hides the fact that your best segment may be worth 4x your worst.
| Segment | ARR/customer | Gross margin % | Annual churn % | CLTV | Max justified CAC (3:1) | Max justified CAC (5:1) |
|---|---|---|---|---|---|---|
| Enterprise | ||||||
| Mid-market | ||||||
| SMB | ||||||
| Self-serve | ||||||
| [Your segment] |
Churn-rate sensitivity table
CLTV is brutally sensitive to churn. Fixed inputs: $24,000 ARR, 78% margin.
| Annual churn rate | CLTV | Change vs. 15% baseline |
|---|---|---|
| 5% | $374,400 | +200% |
| 10% | $187,200 | +50% |
| 15% (baseline) | $124,800 | — |
| 20% | $93,600 | −25% |
| 25% | $74,880 | −40% |
| 30% | $62,400 | −50% |
How to read this: a program that cuts churn from 15% to 10% is worth an incremental $62,400 in lifetime gross margin per customer — multiply by customer count to get the total addressable value of a retention initiative, and use that ceiling to size the budget you're willing to approve for it.
How to use the output
- Calculate blended CLTV first for a baseline.
- Re-run by segment — this is where the real decision-quality lives.
- Compare CLTV:CAC by segment against the benchmark table to find where you're over- or under-investing in acquisition.
- Use the sensitivity table to put a dollar figure on "what would fixing churn by X points be worth" — that figure is your retention program's business case.
How to use it
Drop your own ARR, gross margin %, and annual churn rate into the formulas (or paste them into a spreadsheet), then use the resulting CLTV and CAC:CLTV ratio to size your retention budget and flag which segments deserve more — or less — investment.