CAC vs LTV

CAC vs LTV: The Most Important Ratio in Business

CAC (Customer Acquisition Cost) and LTV (Lifetime Value) are not opposites — they are two sides of the same coin. Together, the LTV:CAC ratio is the single most important health metric for any subscription, e-commerce, or recurring-revenue business. It determines whether your business model is fundamentally sustainable: are you spending less to acquire customers than those customers are worth over time? Improving either number — or the ratio between them — is the core job of a growth team.

What is CAC?

CAC (Customer Acquisition Cost) is the total spend required to acquire one new paying customer, including all marketing, sales, and overhead costs.

Full CAC definition

What is LTV?

LTV (Lifetime Value) is the total net revenue or profit a single customer generates over the entire duration of their relationship with your business.

Full LTV definition

CAC vs LTV: Key Differences

Aspect

CAC

LTV

What it measures

Cost to acquire one customer

Revenue/profit from one customer over time

Time horizon

Point-in-time acquisition cost

Cumulative value over customer lifespan

Influenced by

Ad spend, channel mix, conversion rate

AOV, purchase frequency, retention, churn rate

Goal direction

Minimize (lower is better)

Maximize (higher is better)

Healthy benchmark

LTV:CAC ratio ≥ 3:1

LTV ≥ 3× CAC

Payback period

How long until CAC is recovered by revenue

N/A — LTV is the total recovery

When to use CAC

Evaluating the efficiency of individual acquisition channels (paid search vs. social vs. organic)
Setting maximum bids or CPA targets in ad platforms
Diagnosing whether you can profitably scale a specific channel
Investor reporting on unit economics

When to use LTV

Determining how much you can afford to spend acquiring a customer
Segmenting customers to identify your highest-value cohorts
Improving retention strategy to increase the value of existing customers
Modeling business profitability at scale

Verdict

CAC and LTV must always be read together. A CAC of $200 sounds expensive until you learn the LTV is $1,200 (6:1 ratio — excellent). A CAC of $20 sounds cheap until you learn the LTV is $30 (1.5:1 ratio — unsustainable). The benchmark 3:1 LTV:CAC ratio means you recover acquisition costs 3× over the customer lifetime. Below 1:1, you are destroying value with every customer acquired.