Benchmarks
LTV to CAC ratio for ecommerce: what ratio actually works
Founders love a clean ratio. Investors love a clean ratio. Your bank account loves payback.
LTV:CAC is useful when the inputs are honest. It is dangerous when LTV is revenue cosplay and CAC ignores half the spend.
Answer first
For most €1M to €10M ecommerce brands:
- Use contribution LTV (not pure revenue) over a window you can believe (often 12 months, plus a 90-day early read)
- Use blended CAC that includes media, and the variable creative or affiliate costs you treat like media
- Target a ratio that still leaves room for overhead and profit after payback
- Never scale on ratio alone: payback period must fit your cash cycle
A common rule of thumb is around 3:1 LTV:CAC on contribution. Treat it as a starting band, not a trophy.
The formulas
CAC (blended): sales and marketing spend to acquire new customers in a period, divided by new customers. Be consistent about what you include.
LTV (contribution): average contribution per customer over the window (after COGS, shipping you eat, returns, variable discounts).
Ratio: LTV / CAC.
Payback: months until cumulative contribution from a cohort covers CAC.
If you cannot compute payback, you are not ready to brag about ratio.
Decision rules
| Situation | Move |
|---|---|
| Ratio looks great, payback is 14+ months, cash is tight | Do not scale. Fix offer, margin or mix first. |
| Ratio weak, payback short, contribution strong early | You may have a long-tail LTV problem or a measurement window problem. Diagnose before cutting all spend. |
| Channel ROAS strong, blended CAC weak | Organic and brand are carrying paid. Price that honestly. |
| Ratio falling for three cohorts | Pause "scale" narratives. Find whether CAC rose, LTV fell, or both. |
Worksheet
| Cohort | New customers | Spend in CAC def. | CAC | 90-day contrib LTV | 12-month contrib LTV | Ratio (12m) | Payback months |
|---|---|---|---|---|---|---|---|
Fill this for the last six cohorts before you change budget.
How LTV and CAC usually break
CAC up: auction pressure, creative fatigue, broader targeting, weak landing conversion, attribution fantasy.
LTV down: discount addiction, worse mix, weaker product-market fit in new segments, retention ops slipping.
Rising CAC with flat LTV is how brands get stuck near €1M. See rising CAC and stuck at €1M.
Category humility
Supplements with true repurchase behave differently from one-time furniture. Do not import a SaaS 3:1 myth or a viral brand's screenshot. On a UK subscription supplements engagement, LTV rising about 2.5x changed affordable CAC. Your category physics still win.
What to do Monday
- Lock definitions on one page signed by whoever owns the P&L.
- Build the cohort table above.
- Set a kill rule: if payback exceeds X months, spend cannot rise.
- Put effort into the weaker side of the ratio (LTV or CAC), not into prettier dashboards.
LTV:CAC is a flashlight. Payback and contribution are the ground you walk on.
Questions founders ask
Is 3:1 the right LTV:CAC target?
It is a common rule of thumb, not a law. If LTV is contribution over 12 months and payback is short, 3:1 can be healthy. If LTV is inflated revenue and payback is 18 months, 3:1 can still bankrupt you. Pair ratio with payback and cash.
Should I use blended CAC or channel CAC?
Use blended CAC for company decisions. Use channel CAC for allocation. Optimizing one channel while brand and organic carry the rest will fool you.
How often should I recalculate?
Monthly for directional management, weekly if you are scaling spend hard. Always read recent cohorts, not only lifetime blends.
Next step
Bring your P&L, CAC and LTV. We will tear down what is actually broken, then decide if a deeper engagement makes sense.