Are you buying customersat a profit?
One ratio tells you whether your growth engine compounds money or quietly burns it. Get your LTV:CAC ratio and how many months it takes to earn an acquisition back, the two numbers investors and operators actually trust.
Your numbers
Margin adjusted lifetime value of a customer.
Cost to acquire one customer.
Profit a customer generates each month (for payback).
The verdict
LTV:CAC ratio
3.6 : 1
CAC payback
5.6
Months to earn it back.
Profit per customer
$650
Max CAC at 3:1
$300
Ceiling to stay healthy.
Value vs cost vs the 3:1 ceiling
Reverse-solve · hit a target ratio
What gets you to a healthy ratio?
Max CAC allowed
$300
Or LTV needed
$750
To hit 3.0 : 1 you either keep CAC under $300(you're at $250) or lift LTV to $750 (you're at $900). Raising LTV through retention is usually the more durable of the two.
Sensitivity · the cost of CAC creep
Ratio & payback as CAC moves
| CAC | LTV:CAC | Payback |
|---|---|---|
| $125 | 7.2 : 1 | 2.8 mo |
| $188 | 4.8 : 1 | 4.2 mo |
| $250 | 3.6 : 1 | 5.6 mo |
| $313 | 2.9 : 1 | 6.9 mo |
| $375 | 2.4 : 1 | 8.3 mo |
| $500 | 1.8 : 1 | 11.1 mo |
As CAC rises, the ratio and the payback both deteriorate — and payback is the one that quietly starves cash, because the money comes back too slowly to refuel the next cohort.
Your move
A healthy ratio is permission to scale. Let's earn it.
LTV:CAC 3.6 : 1 with a 5.6-month payback.
Whether your ratio says 'fix it' or 'pour fuel on it,' the next move depends on which lever pays fastest. Send me your numbers and I'll show you whether to grow LTV, cut CAC, or open the throttle.
Plain English
The ratio that decides if growth is real.
LTV:CAC compares what a customer is worth (lifetime value) to what it cost to win them (acquisition cost). It's the clearest single read on whether your marketing is an investment or an expense.
The rule of thumb is 3:1, every dollar of acquisition should return three of margin adjusted lifetime value. Below that, you're paying too much for too little. Far above it (5:1+) usually means you're being too cautious and leaving growth on the table.
But the ratio alone can hide a cash trap. A great 4:1 with a two year payback can still starve you, because the money comes back too slowly to refuel acquisition. That's why payback period sits right next to the ratio, one measures profitability, the other measures speed.
The formula
LTV:CAC = LTV ÷ CAC · Payback = CAC ÷ monthly gross profit
$900 LTV ÷ $250 CAC = 3.6:1, healthy. At $45 monthly gross profit per customer, payback = $250 ÷ $45 ≈ 5.6 months, fast enough to recycle into the next cohort.
What the ratio should be
LTV:CAC is one of the few metrics with a near universal benchmark. Where your ratio lands tells you whether to scale, hold, or fix the economics first:
| Zone | Ratio | What it means |
|---|---|---|
| Losing money | Under 1:1 | Each customer costs more than they're worth |
| Surviving | 1:1 to 3:1 | Acquisition too expensive for the value |
| Healthy | 3:1 to 5:1 | The zone to scale from |
| Under-investing | 5:1 and up | Likely room to spend more, grow faster |
Source: Klipfolio / HBS SaaS unit-economics guidance · 2025
Read your ratio
Ratio below 1:1.
You lose money on every customer. Stop scaling spend now, fix LTV or CAC before another dollar goes out the door.
Ratio 1 to 3:1.
Surviving, not thriving. Acquisition is too expensive relative to value. Lift retention and AOV, or cut CAC, to reach the 3:1 floor.
Ratio 3 to 5:1.
The healthy zone. Now press the advantage, scale spend while the ratio holds and watch payback so cash doesn't choke.
Ratio above 5:1.
Often a sign of under investment. You can likely spend more to grow faster without breaking unit economics. Test scaling acquisition.
Fix the ratio from both ends
01Raise LTV first
Retention and AOV lift the numerator without touching ad costs, the most durable fix.
02Cut CAC with conversion
A better funnel lowers acquisition cost across every channel at once.
03Shorten payback
Upfront offers and annual plans pull profit forward so cash recycles faster.
04Kill weak channels
Reallocate from high CAC channels to the ones with the best ratio.
05Engineer the second purchase
Repeat orders raise LTV dramatically and improve the ratio fast.
06Segment the ratio
Blended numbers hide losers. Compute LTV:CAC per channel and cut the unprofitable ones.
The vocabulary
- LTV:CAC
- Ratio of customer lifetime value to acquisition cost; 3:1+ is the healthy benchmark.
- CAC payback
- Months of gross profit needed to earn back the cost of acquiring a customer.
- Unit economics
- The profitability of a single customer, the foundation LTV:CAC measures.
- Margin adjusted LTV
- Lifetime value after product cost, the correct numerator for this ratio.
- Cohort
- A group of customers acquired in the same period, tracked over time.
LTV:CAC questions
3:1 is the widely accepted healthy benchmark, three dollars of lifetime value for every dollar of acquisition cost. Below 3 acquisition is too expensive; above 5 you may be under investing in growth.
Keep going
A calculator tells you what. A call tells you what to do about it.
Send me the account behind these numbers. I'll tell you straight where the money's leaking and what I'd fix first — free, and you keep it whether you hire me or not.