What Is a Good LTV to CAC Ratio for Ecommerce?
What is a good LTV to CAC ratio for an ecommerce brand?
3:1 is the usual target, but it is a convention borrowed from SaaS, not an ecommerce standard: David Skok wrote that the best SaaS businesses run above 3. For a store, measure LTV on contribution margin, not revenue, over a window you have observed, such as 12 months. Below 1:1, the average customer costs more than they return.
Aim for a ratio comfortably above 1:1 on margin you have actually banked, and use 3:1 as a planning convention rather than a pass mark. The number only means something if both halves are honest: LTV built from contribution margin per customer, not revenue, and CAC built from paid spend over new customers that paid ads brought in. Get either half wrong and a healthy-looking 3:1 can hide a business that loses money on every cohort.
Where does the 3:1 LTV to CAC rule come from?
It comes from subscription software. In his guide SaaS Metrics 2.0, David Skok writes that the best SaaS businesses have an LTV to CAC ratio higher than 3, sometimes as high as 7 or 8. He pairs it with a second rule: the best recover their CAC in 5 to 7 months, and profitability becomes anemic when recovery takes more than 12.
Nobody has published an equivalent study for ecommerce that we could find, so 3:1 is a convention, not a measured benchmark for stores. It travels reasonably well because the logic is the same: the margin a customer returns has to pay for acquiring them, for the overhead that acquisition does not cover, and for the time the money is tied up. What travels badly is a predicted lifetime: a store’s repeat buying is usually less regular than a monthly subscription, so a lifetime projected from early months is riskier.
Andreessen Horowitz’s 16 Startup Metrics (Jordan, Hariharan, Chen and Kasireddy, 21 Aug 2015) gives the version that fits ecommerce: LTV is the net profit from a customer over the relationship, built from contribution margin, and the contribution-margin LTV to CAC ratio is the one to manage spend against.
How do you calculate LTV to CAC for an online store?
Use observed numbers for one acquisition cohort, for example every customer whose first order came in January:
- Count new customers: in Shopify, go to Analytics, then Reports, and open Customer cohort analysis, which groups customers by first order date (Shopify Help Center).
- Calculate paid CAC: divide ad spend for that month by the new customers paid ads brought in. a16z calls this paid CAC, as opposed to blended CAC over all channels.
- Read net sales per customer for the cohort over 12 months, using the report’s Metric menu.
- Convert net sales to contribution margin: subtract product cost, shipping, payment fees, packaging and returns. Use your own percentage, not a guess.
- Divide 12-month contribution margin per customer by paid CAC. That is your ratio.
A worked example with illustrative numbers, not a benchmark: a January cohort cost $12,000 in ads and brought 400 new customers, a paid CAC of $30. Over 12 months those customers spent $150 each in net sales. At a 40% contribution margin that is $60 per customer, so the ratio is $60 ÷ $30 = 2:1. On revenue the same cohort would read $150 ÷ $30 = 5:1, which is exactly the mistake a16z warns against: estimating LTV from revenue or gross margin instead of profit.
For the full cohort build, including churn, refunds and stop rules, see how do I calculate the real value of an acquired cohort?
What LTV to CAC ratio should an ecommerce brand aim for?
Read the ratio in bands, using contribution margin over an observed 12 months. The bands below are our working interpretation of the 3:1 convention, not a published standard.
| Ratio (12-month contribution LTV ÷ paid CAC) | What it means | What to do |
|---|---|---|
| Below 1:1 | The average customer returns less margin than they cost to acquire | Cut CAC or raise first-order margin before scaling spend |
| 1:1 to 2:1 | Acquisition pays for itself, with little left for overhead | Hold spend steady and work on repeat rate and average order value |
| 2:1 to 3:1 | Acquisition funds itself and contributes to fixed costs | Scale carefully and watch payback time and cash |
| Above 3:1 | Meets the SaaS convention on margin you have banked | Test more spend, since a high ratio can mean you are under-investing |
Two adjustments matter more than the band. If your customers rarely reorder, a 12-month window and a first-order window give almost the same answer, so judge the first order on its own. And if you only have 3 months of data, compare a 3-month ratio with your earlier cohorts at 3 months rather than extrapolating to 12.
Why can a 3:1 ratio still lose money?
Four errors inflate the ratio without changing the bank balance:
- Revenue instead of margin. A $150 customer at 40% contribution margin is a $60 customer. At a contribution margin between 33% and 50%, revenue-based LTV overstates the ratio 2 to 3 times.
- Blended CAC instead of paid CAC. Dividing ad spend by all new customers, including those from email, search and word of mouth, makes paid acquisition look cheaper than it is. Reconcile channels first: how do I calculate blended CAC across channels?
- Platform-attributed customers. Ads Manager counts conversions within its attribution setting, and other ad platforms may claim the same purchase. Count new customers from your store, not from the ad platform; can I trust my Facebook ROAS? covers what to check.
- Predicted lifetime. A model that projects 36 months of repeat buying from 6 months of data turns hope into LTV. Shopify’s predicted spend tier, for example, ranks customers by predicted value; it is a targeting aid, not banked margin.
The ratio also ignores time. A 3:1 ratio that takes 20 months to arrive can strain cash in a way a 2:1 ratio that arrives in 2 months does not. Whether a first-order loss is worth carrying is its own decision: when is it acceptable to lose money on the first order?
Is a higher LTV to CAC ratio always better?
No. Skok notes that the best SaaS businesses reach 7 or 8, but a very high ratio in a store can mean one of two things: you are spending too little to reach the customers who would still be profitable at a higher CAC, or your measurement is flattering the numerator. Before celebrating a 6:1, check that LTV is margin, that CAC is paid-only, and that the cohort is old enough to have earned what you are crediting it with. If all three hold, raise spend in steps and watch whether the next cohort’s ratio holds.
Can software help?
Bach.ai (by Wittelsbach) connects to a Meta ad account, audits it daily, finds revenue leaks with an estimated revenue impact, and proposes fixes. On every plan, it applies a change on Meta only after you approve it.
FAQ
What is a good LTV to CAC ratio for a new store?
Aim first for above 1:1 on the first order, because a new store has no repeat history to lean on. Once you have 6 to 12 months of cohorts, measure contribution-margin LTV over the window you have actually observed and move toward the 3:1 convention.
Should LTV use revenue or profit?
Profit. Use contribution margin per customer: net sales minus product cost, shipping, payment fees, packaging and returns. a16z calls estimating LTV from revenue or gross margin a common mistake, and at a 40% margin a revenue-based ratio reads 2.5 times higher than the real one.
How long a window should LTV cover?
Use a window you have already observed. a16z suggests measuring 12-month and 24-month LTV from historical data rather than predictions, and 12 months keeps the number close to cash. If your product is bought once, the first-order window is the honest one; a longer window adds little but noise.
Does Meta report LTV to CAC?
No. Ads Manager reports cost per purchase and purchase value within your attribution setting. It does not know your margins or which buyers are new to your store, so build the ratio from store data and your own cost figures.
Sources
Sources: David Skok, SaaS Metrics 2.0; Jeff Jordan, Anu Hariharan, Frank Chen and Preethi Kasireddy, 16 Startup Metrics, Andreessen Horowitz, 21 Aug 2015; Shopify Help Center, Customers reports (checked 2 Oct 2026).