What is a good LTV to CAC ratio?

In a subscription business, two numbers decide whether growth makes you richer or poorer: how much a customer is worth over their lifetime (LTV), and how much it costs to win them (CAC). Founders, investors and marketing teams usually look at the ratio between the two before anything else.

This article covers how to calculate both numbers, what ratio is usually considered healthy, and what moves it. You can follow along with your own figures in the SaaS metrics calculator.

What LTV and CAC mean

Customer lifetime value (LTV) is the gross profit you expect from an average customer before they cancel. Hosting, support, payment fees and the other costs of delivering the product come out first, so LTV is smaller than the revenue a customer brings in.

Customer acquisition cost (CAC) is what you spend on sales and marketing to win one new customer: total sales and marketing spend in a period divided by the new customers gained in that period.

LTV:CAC divides the first by the second. At 3:1, each customer brings in three dollars of gross profit for every dollar spent to acquire them.

How to calculate LTV

The simplest version works for most early-stage products and needs three inputs. ARPU is average revenue per user per month (MRR ÷ paying customers). Gross margin is the share of revenue left after the direct costs of serving customers. Monthly churn is the share of customers who cancel each month.

LTV = ARPU × gross margin ÷ monthly churn rate

The division by churn comes from the average customer lifetime. If 4 % of customers cancel every month, the average customer stays about 1 ÷ 0.04 = 25 months.

A worked example

A product has $10,000 in MRR from 200 customers, a gross margin of 80 % and monthly churn of 3 %. It spends $400 on average to acquire a customer.

• ARPU: $10,000 ÷ 200 = $50 per month
• Gross profit per customer per month: $50 × 0.8 = $40
• Average lifetime: 1 ÷ 0.03 ≈ 33 months
• LTV: $40 ÷ 0.03 ≈ $1,333
• LTV:CAC: $1,333 ÷ $400 ≈ 3.3 : 1

So what ratio is good?

The figure you will hear most often is 3:1. It is a rule of thumb, and the reasoning behind it holds up. Acquisition cost is paid up front while the profit arrives over months or years, some customers leave earlier than average, and the business has costs LTV does not cover, like product development and administration. A ratio around 3:1 leaves room for all of that and still produces a profit.

A rough way to read your number:

• Below 1:1, you lose money on every customer you acquire, and growing faster makes the problem bigger.
• Between 1:1 and 3:1, each customer pays back their acquisition cost, but there may not be enough left to cover the rest of the business. This usually means working on retention, pricing or acquisition efficiency before scaling spend.
• Around 3:1 to 5:1 is generally treated as healthy.
• Well above 5:1, the unit economics are good, but you may be under-investing in growth. If each customer is that profitable, more marketing spend might bring in more total profit even as the ratio falls.

The right target also depends on how fast you get your money back.

CAC payback

Two companies can both sit at 3:1 and be in very different situations if one recovers its acquisition cost in 6 months and the other in 30. The second needs far more cash to grow and carries more risk if customers churn earlier than expected.

CAC payback (months) = CAC ÷ (ARPU × gross margin)

In the example above, $400 ÷ $40 = 10 months. With a shorter payback, the money spent on acquisition comes back sooner and can be reinvested. Read LTV:CAC and payback together.

Common mistakes when calculating the ratio

The most common one is using revenue instead of gross profit. Leaving out gross margin makes LTV look bigger than it is: at a 70 % margin, revenue-based LTV overstates the real value by more than 40 %.

The second is leaving costs out of CAC. It should include everything you spend to acquire customers, including ad spend, sales salaries and commissions, marketing tools, agency fees and content production. Counting only ads makes acquisition look cheaper than it is.

Mixing periods causes large errors. If you use monthly churn, use monthly ARPU; annual revenue with monthly churn inflates LTV by a factor of 12.

Churn from a very young product is another trap. With only a few months of data the numbers are noisy and often too optimistic, and early adopters tend to behave differently from later customers. Treat early LTV estimates as rough and update them as cohorts age. If nobody has cancelled yet, the formula divides by zero and gives infinite LTV, so use a conservative assumption until you have real data.

Finally, a single average can hide a lot. If you sell both small self-serve plans and large annual contracts, calculate the ratio per segment or per channel.

How to improve a low LTV to CAC ratio

You can make customers more valuable, make them cheaper to acquire, or both.

Increase LTV

Churn sits in the denominator, so reducing it has an outsized effect. In the example above, cutting monthly churn from 3 % to 2 % raises LTV from $1,333 to $2,000 with nothing else changed. Better onboarding, fixing the reasons people cancel and offering annual plans are common places to start.

Many young products are underpriced. Add-ons, usage-based tiers and upgrades for heavy users can raise revenue per customer. Gross margin is the third lever: lower hosting costs, reduce support load with better documentation, and negotiate payment fees as you grow.

Reduce CAC

Calculate CAC per channel rather than blended. Once they are running, referral programs, content and search traffic often cost less per customer than paid ads. A better landing page or trial experience lowers CAC across every channel at once, because the same spend produces more customers. Customers who fit the product well also tend to convert more easily and stay longer, which helps both sides of the ratio.

When the ratio is very high

A ratio far above 5:1 is still worth questioning. You may be growing more slowly than you could. If the market is large and payback is short, more marketing spend may bring in more total profit, even though the ratio will drop as you move into more expensive channels.

It can also mean the numbers are wrong. Check that CAC includes all acquisition costs and that churn is measured over a long enough period.

You can try different scenarios in the SaaS metrics calculator. Change churn by one percentage point and watch what happens to LTV.