LTV to CAC Ratio: How to Calculate It and What Counts as Good
Learn what LTV and CAC mean, how to calculate the LTV to CAC ratio step by step, and why gross margin and blended averages can mislead you.
TL;DR. The LTV to CAC ratio compares the gross profit you expect from a customer over their lifetime with what it cost to acquire them. A ratio around 3:1 is often quoted as healthy, but treat it as a rule of thumb rather than a measured standard. Whether your ratio is good depends on how you calculate it, which segment you look at and how long you wait to recover the cost. Calculate LTV on gross margin rather than revenue, split the ratio by segment and channel, and read it alongside CAC payback.
What do LTV and CAC mean?
Customer lifetime value (LTV) is the gross profit you expect to earn from a customer over the whole time they stay with you. It is an estimate about the future, built from current revenue, margin and churn.
Customer acquisition cost (CAC) is what you spend in sales and marketing to win one new customer. It is a record of the past: costs over a period divided by the new customers acquired in that period.
The ratio divides one by the other:
LTV to CAC ratio = LTV ÷ CAC
A ratio of 3:1 means each customer is expected to return three units of gross profit for every unit spent to acquire them. For definitions of related terms, see the SaaS Metrics Glossary.
How do you calculate the LTV to CAC ratio?
Work through four steps. The numbers below are illustrative only and describe a hypothetical subscription business.
Step 1: Find average revenue per account. Suppose the average customer pays 500 per month.
Step 2: Apply gross margin. If gross margin is 80%, each customer contributes 400 per month in gross profit (500 × 0.80).
Step 3: Estimate customer lifetime. A common simplification is lifetime = 1 ÷ monthly churn rate. With 2.5% monthly customer churn, the expected lifetime is 40 months (1 ÷ 0.025).
LTV = 400 × 40 = 16,000
Step 4: Calculate CAC. Suppose you spent 300,000 on sales and marketing last quarter and won 60 new customers. CAC = 300,000 ÷ 60 = 5,000.
LTV to CAC = 16,000 ÷ 5,000 = 3.2:1
| Input | Illustrative value | How it is derived |
|---|---|---|
| Monthly revenue per account | 500 | Billing data, new and existing customers in the segment |
| Gross margin | 80% | Revenue minus cost of delivering the service |
| Monthly gross profit per account | 400 | 500 × 0.80 |
| Monthly customer churn | 2.5% | Customers lost ÷ customers at start of month |
| Expected lifetime (months) | 40 | 1 ÷ 0.025 |
| LTV | 16,000 | 400 × 40 |
| CAC | 5,000 | 300,000 ÷ 60 new customers |
| LTV to CAC | 3.2:1 | 16,000 ÷ 5,000 |
The formula for lifetime assumes churn stays constant. In practice it rarely does, so treat the result as a model, not a forecast. Calculate SaaS Cohort Retention shows how to check churn by the month customers joined.
What is a good LTV to CAC ratio?
The figure most often repeated is around 3:1. Treat it as a rule of thumb that people use for discussion, not as a measured industry standard.
A more useful way to read the ratio is directionally:
| Ratio range | Common reading | Question to ask |
|---|---|---|
| Below 1:1 | Each customer costs more to win than they return | Is this a deliberate early investment or a broken channel? |
| Around 1:1 to 3:1 | Thin returns once overheads are counted | Can you raise retention, margin or price, or cut acquisition cost? |
| Around 3:1 | Often described as balanced | Is the payback time acceptable for your cash position? |
| Well above 3:1 | Strong returns per customer | Are you underinvesting in growth you could profitably buy? |
A high ratio is not automatically good. It can mean you are spending too little on acquisition and leaving growth on the table. A low ratio can be acceptable for a short period while you test a new channel, provided you know why it is low and what would improve it.
Why does the ratio need a payback check?
The ratio says nothing about when you get the money back. A 3:1 ratio earned over seven years puts far more strain on cash than the same ratio earned over three.
Using the illustrative numbers above, CAC of 5,000 divided by 400 of monthly gross profit gives a payback of 12.5 months. How to Calculate SaaS CAC Payback Period covers that calculation in detail. Read the two together: the ratio tells you whether customers are worth acquiring, and payback tells you whether you can afford to keep acquiring them.
What are the common mistakes?
Using revenue instead of gross margin. If you calculate LTV on revenue, the illustrative example becomes 20,000 instead of 16,000 and the ratio jumps to 4:1. CAC is paid in real cash, so compare it with the profit customers generate, not their top-line spend. Include hosting, support and onboarding costs in cost of revenue.
Blending segments into one average. Suppose small accounts have a ratio of 1.5:1 and large accounts 5:1. A blended figure of around 3:1 looks healthy while one segment loses money on every deal. Calculate the ratio separately by segment, plan and acquisition channel. Prioritize B2B Customer Segments can help decide which splits matter.
Leaving costs out of CAC. Count salaries, commissions, tools, agency fees and paid media for sales and marketing, not only ad spend. Be consistent about whether you include the cost of acquiring expansion revenue.
Mismatching time periods. Spend in one quarter often produces customers in the next, particularly with long sales cycles. Lag the customer count to match how long deals take to close.
Trusting a lifetime estimate from young data. If your oldest customers joined recently, a low early churn rate can produce an implausibly long lifetime. Cap lifetime at a period you can defend, and say so when you report the number.
Ignoring expansion and contraction. Upgrades raise LTV and downgrades lower it. If expansion is significant, consider revenue retention alongside logo churn; see Net Revenue Retention Explained and Logo Churn vs Revenue Churn.
When does the LTV to CAC ratio not apply well?
The ratio is weakest when its inputs are guesses. Very early companies with few customers and little churn history should focus on retention evidence and payback rather than a lifetime estimate. Businesses with large one-off services fees or usage-based pricing need to decide what counts as recurring gross profit before the ratio means anything; How to Calculate SaaS ARR with Services and Usage Fees covers that separation. Product-led businesses with many self-serve sign-ups may also find CAC hard to attribute by channel, so state the method you used.
What should you check before reporting the ratio?
- LTV is based on gross profit, not revenue.
- Gross margin includes the real costs of delivering and supporting the service.
- CAC includes all sales and marketing costs for the period, with the method written down.
- The ratio is shown by segment and channel, not only as a blended total.
- The lifetime assumption is stated and capped if churn history is short.
- CAC payback is reported alongside the ratio.
- Any benchmark you mention is labeled as a rule of thumb.
What else should you know about LTV to CAC?
Frequently asked questions
What is a good LTV to CAC ratio?
Around 3:1 is a commonly quoted rule of thumb, not a measured standard. Judge your ratio by segment, alongside CAC payback and your cash position.
Should LTV use revenue or gross margin?
Gross margin. Acquisition costs are paid in cash, so compare them with the profit a customer generates after the cost of delivering the service.
Can an LTV to CAC ratio be too high?
Yes. A very high ratio can mean you are underinvesting in acquisition and could grow faster while remaining profitable per customer.
How often should you recalculate the ratio?
Recalculate it on a regular reporting cycle, such as quarterly, and whenever pricing, churn or acquisition spend changes noticeably.
Why does my blended ratio look healthy when some deals lose money?
Averages hide differences between segments. Strong economics in one group can offset losses in another, so calculate the ratio for each segment and channel.
If you want help applying this to your own team, talk to us.
Related reading
- How to Calculate SaaS CAC Payback Period — see how long it takes to recover acquisition cost.
- SaaS Metrics Glossary — definitions for the metrics used in this guide.
- Net Revenue Retention Explained — account for expansion and contraction in customer value.
- Calculate SaaS Cohort Retention — test the churn assumptions behind LTV.
- SaaS Quick Ratio Explained — another way to read growth efficiency.
Related reading
SaaS Quick Ratio: What It Tells You and What It Hides
Learn how to calculate the SaaS quick ratio, work through an illustrative example, and read it alongside net revenue retention and logo churn.
How to Calculate SaaS CAC Payback Period
Calculate SaaS CAC payback period with a worked example covering acquisition costs, gross margin, sales-cycle timing and customer segments.
How to Calculate ARR With Services and Usage Fees
Separate subscriptions, services and usage fees to calculate ARR, handle discounts and minimum commitments, and document uncertain usage revenue.
How to Calculate SaaS Cohort Retention
Calculate SaaS cohort retention with fixed denominators, clear retention rules and a worked example covering incomplete periods and reactivated customers.