How To Calculate Customer Acquisition Cost (CAC) And LTV:CAC
Dominic Tarn
Head of Content
10.13.2026
Customer acquisition cost (CAC) is the total sales and marketing spend needed to win one new customer. The basic formula is CAC = total sales and marketing costs in a period ÷ number of new customers acquired in that period. To judge whether that cost is healthy, compare it to customer lifetime value (LTV), the gross profit a customer generates over their relationship with you. A widely used rule of thumb is an LTV:CAC ratio of about 3:1, with the cost recovered within roughly 12 months.
CAC and LTV are two of the most important numbers in any growing business, and two of the most often miscalculated. This guide shows the formulas, walks through a worked example, explains which costs to include and covers the common mistakes that make CAC look better than it really is.
Use the same time period for costs and customers, usually a month or a quarter. If your sales cycle is long, consider lagging the customer count, for example by comparing one quarter’s spend with the next quarter’s new customers, so the costs line up with the customers they produced.
There are two versions worth tracking:
Metric
Formula
Use It For
Blended CAC
All sales and marketing costs ÷ all new customers (including organic and referrals)
Overall efficiency and investor reporting
Paid or channel CAC
Spend on one channel ÷ customers from that channel
Deciding where to put the next dollar
Blended CAC usually looks better because organic customers lower the average. Paid CAC tells you whether a specific channel can scale profitably.
Which Costs Should You Include In CAC?
Include
Usually Exclude
Advertising spend across all channels
Customer success and support for existing customers
Salaries, commissions and benefits for sales and marketing staff
Product development
Agency, freelancer and contractor fees
Account management focused on retention
Marketing and sales software (CRM, automation, analytics)
General company overhead unrelated to acquisition
Content, events, sponsorships and PR
Free trials or onboarding costs directly tied to winning customers
Leaving out salaries and tools is the most common way companies understate CAC. A “fully loaded” CAC that includes people and software is the honest number.
How Do You Calculate Customer Lifetime Value?
For subscription businesses, a simple and widely used formula is:
LTV = (Average revenue per customer per month × Gross margin %) ÷ Monthly churn rate
For non-subscription businesses:
LTV = Average order value × Purchases per year × Average customer lifespan in years × Gross margin %
Use gross margin, not revenue. A customer paying $100 a month at a 70% gross margin contributes $70 a month toward covering acquisition and overhead.
What Is A Good LTV:CAC Ratio?
LTV:CAC Ratio
What It Usually Signals
Below 1:1
You lose money on each customer. Fix pricing, retention or acquisition before scaling.
1:1 to 3:1
Marginal. Growth may be possible but is capital-intensive.
About 3:1
The widely cited healthy benchmark for scaling.
Well above 5:1
Efficient, but possibly under-investing in growth. Test spending more.
The 3:1 benchmark is a rule of thumb from venture-backed SaaS, not a law. Businesses with very high retention or low capital costs can operate profitably at different ratios. Track the trend over time as closely as the absolute number.
Payback tells you how long cash is tied up in each new customer. Shorter is better because it lets you reinvest in growth sooner. Many SaaS investors look for payback under about 12 months for small business customers, accepting longer periods for enterprise deals with higher retention.
Worked Example
A software company spends the following in one quarter:
Cost
Amount
Paid ads
$60,000
Sales and marketing salaries
$90,000
Agency and freelancer fees
$20,000
Software and tools
$10,000
Total
$180,000
It wins 120 new customers in the quarter.
CAC = $180,000 ÷ 120 = $1,500
Customers pay $200 a month at an 80% gross margin, so each contributes $160 a month.
Monthly churn is 2%, so LTV = $160 ÷ 0.02 = $8,000
LTV:CAC = $8,000 ÷ $1,500 = 5.3:1
Payback = $1,500 ÷ $160 = about 9.4 months
If the company had counted only ad spend, CAC would appear to be $500 and the ratio 16:1, which would badly overstate how efficiently it acquires customers.
Common CAC Mistakes
Counting only ad spend. People and tools are often the largest part of acquisition cost.
Mismatched time periods. Long sales cycles mean this month’s customers came from last quarter’s spend.
Using revenue instead of gross margin in LTV. This inflates LTV and makes the ratio look healthier.
Optimistic churn assumptions. New businesses often lack enough history; use conservative estimates and update them.
Only tracking blended CAC. A strong organic channel can hide a paid channel that loses money.
Ignoring segments. Enterprise and small business customers often have very different CAC and LTV. Calculate them separately.
How Do You Lower CAC Or Raise LTV?
To lower CAC:
Improve conversion rates on landing pages, trials and demos before buying more traffic.
Shift budget toward channels with proven payback and cut channels that never reach it.
Invest in compounding channels such as SEO, content, partnerships and referrals.
Tighten targeting so sales time goes to prospects who match your best customers.
Earn mentions in the listicles, reviews and comparison pages that buyers and AI assistants consult when shortlisting vendors.
To raise LTV:
Reduce churn with better onboarding and proactive customer success.
Add expansion revenue through upgrades, add-ons and usage-based pricing.
Review pricing; many businesses undercharge relative to the value they deliver.
There is no universal number. A CAC is “good” when it is comfortably below the gross profit a customer generates over their lifetime, ideally with an LTV:CAC ratio around 3:1 or better and payback within about a year.
Should CAC include salaries?
Yes, for fully loaded CAC. Include the salaries, commissions and benefits of people whose work is focused on acquiring new customers.
How often should I calculate CAC?
Monthly for channel decisions and quarterly for board and investor reporting, using consistent definitions each time.
What is the difference between CAC and cost per lead?
Cost per lead measures the cost of generating a prospect. CAC measures the cost of winning a paying customer, which includes the cost of all the leads that did not convert.
The Short Version
Calculate CAC by dividing all sales and marketing costs, including people and tools, by new customers in the same period. Calculate LTV using gross margin and realistic churn. Aim for an LTV:CAC ratio around 3:1 and payback within about 12 months, track paid and blended CAC separately, and improve the numbers by fixing conversion and retention before buying more traffic.
