LTV:CAC ratio: formula, calculator and benchmarks

LTV:CAC calculator with payback period

The calculator builds LTV from order value, purchase frequency, lifespan and contribution margin. It then compares LTV with your acquisition cost and shows how many months a new customer needs to pay back what you spent to win them.

LTV:CAC formula with a worked example

LTV (lifetime value) is the contribution margin a customer brings over the whole relationship. CAC (customer acquisition cost) is what you spend on average to win one new customer.

The example is healthy. The store could spend $20 more per new customer and still sit at the 3 to 1 benchmark.

What is a good LTV to CAC ratio?

The 3 to 1 benchmark comes from David Skok's guide "SaaS Metrics 2.0". He writes that the best SaaS businesses run an LTV to CAC ratio above 3, some as high as 7 or 8. He adds a second test: the best recover CAC in 5 to 7 months, and profitability turns anemic once recovery takes longer than 12 months. For online stores the rule works as a starting point, as long as you calculate LTV on contribution margin.

A high ratio is not a goal in itself. At 8 to 1 you are probably winning too few customers. More budget lowers the ratio, and total profit can still rise.

CAC payback period: when a new customer pays off

The ratio tells you whether a customer pays off. The payback period tells you when. For cash flow, the second number matters more: until payback, you finance every new customer out of your own pocket.

Every row uses $240 LTV and $6.67 in contribution margin per month. At $120 CAC you wait a year and a half for your money, and every customer who drops out before then widens the gap.

Stores that sell consumables such as coffee, pet food or supplements can hit 12 months, because customers reorder several times a year. For furniture or electronics bought once every few years, the first order has to carry most of the CAC by itself.

LTV:CAC in e-commerce vs SaaS

Most guides on the ratio come from SaaS. There, LTV comes from monthly revenue per account and the monthly churn rate. Online stores have no subscriptions to cancel. Customers stop ordering at some point.

The cost block makes the biggest difference. A store pays for product, shipping and returns on every order, software pays almost nothing. Calculate LTV on revenue and a retailer overstates it far more than a SaaS company would. In the example above, by a factor of 2.5.

Blended CAC or paid CAC: which one belongs in the ratio

You can calculate CAC two ways. Blended CAC divides all marketing costs by all new customers, including those who came through referrals or organic search. Paid CAC divides ad spend by the new customers who came through ads.

Use blended CAC to judge whether the business model holds. Use paid CAC for budget decisions inside the ad account. If many customers arrive organically, blended CAC flatters your ads. The store-wide counterpart on the revenue side is the marketing efficiency ratio: all revenue divided by all marketing spend.

Four common calculation mistakes

1. LTV on revenue. $600 in revenue ÷ $60 CAC gives 10 to 1. On contribution margin it is 4 to 1.
2. Ad spend only in CAC. New customer discounts, agency fees and creator costs belong in it too. Leave them out and CAC looks cheaper than it is.
3. All customers in the CAC denominator. Divide by new customers only. Returning customers who click an ad would push CAC down artificially.
4. Lifespan too long. Assume five years in a store that is three years old and you count purchases nobody has made. Use what your cohorts show.

How to improve your LTV:CAC ratio

You have two sides to work on: lower CAC or raise LTV. You work on CAC in the ad accounts, on LTV through assortment, pricing and retention.

• Lower CAC: pull budget from campaigns that only collect existing customers or brand searches. The ROAS formula page shows the point where a campaign starts losing money.
• Read campaigns correctly: what a ROAS number in the ad account tells you and what it hides is covered under ROAS meaning.
• Raise LTV: more orders per customer through email, WhatsApp and winback flows. Those purchases cost no ad budget. The cost of customer retention and how the setup works are on our retention page.
• Raise contribution margin: fewer discounts, fewer returns, bundles instead of single items. Every point of margin lifts LTV and the ratio together.

Run the numbers on the first order: an $80 order at $60 CAC is a ROAS of 1.33 on revenue you keep. That order brings $32 in contribution margin, so the new customer starts $28 in the red. Repeat orders make them profitable.

Harucon works both sides at once: cut budget that does nothing and bring existing customers back through retention. What that delivered is in our results.