Customer Acquisition Cost (CAC) is the total cost of acquiring a single new customer. It includes every dollar spent on marketing, sales, and related overhead - divided by the number of new customers those dollars produced.
CAC is half of the most important equation in SaaS: LTV:CAC. Without knowing what it costs you to acquire a customer, you can't know whether that customer is worth what you paid to get them.
What Is CAC?
CAC is a fully-loaded measure of acquisition efficiency. The goal is to understand the true cost of adding a new paying customer - not just ad spend, but all associated costs.
A business with $100,000 in monthly sales and marketing spend that acquires 200 new customers has a CAC of $500. Whether that's good or bad depends entirely on the LTV of those customers.
🧒 Explained simply You spend your pocket money making 20 flyers and sticking them around the neighbourhood to get new lemonade customers. That costs you $5. If 2 kids show up because of your flyers, each new customer "cost" you $2.50 to get. That's CAC. The big question is: will those 2 kids spend more than $2.50 at your stand over time? If yes, the flyers were worth it.
How to Calculate CAC
Basic CAC Formula
CAC = Total Sales & Marketing Spend ÷ New Customers Acquired
Example: You spend $50,000 on marketing and sales in a quarter and acquire 100 new customers.
CAC = $50,000 ÷ 100 = $500
What to Include in "Sales & Marketing Spend"
The accuracy of your CAC depends on how fully-loaded your cost calculation is:
Include:
- Paid advertising (search, social, display)
- Content marketing production costs
- SEO tools and agency fees
- Sales team salaries and commissions
- Marketing team salaries
- CRM and sales tools
- Events and sponsorships
- Affiliate and referral payouts
Exclude:
- Customer success costs (these relate to retention, not acquisition)
- Product development (unless it's specifically acquisition-focused)
- General overhead not directly tied to acquiring customers
A common mistake is using only ad spend as the denominator and ignoring sales salaries, tools, and overhead. This produces an artificially low CAC that doesn't reflect the true cost of growth.
Blended vs Channel-Level CAC
Blended CAC is the average across all acquisition channels. It's useful for overall unit economics calculations.
Channel-level CAC breaks down cost per customer by acquisition source: paid search, content, referral, outbound, etc. This is far more actionable - it tells you which channels are producing customers efficiently and which are not.
| Channel | Spend | New Customers | CAC |
|---|---|---|---|
| Paid Search | $20,000 | 30 | $667 |
| Content/SEO | $8,000 | 40 | $200 |
| Outbound Sales | $15,000 | 15 | $1,000 |
| Referral | $5,000 | 20 | $250 |
| Total | $48,000 | 105 | $457 |
In this example, content and referral are the most efficient channels by CAC. But the story isn't complete without LTV - a $1,000 CAC from outbound might be fine if those customers have an LTV of $8,000.
CAC Payback Period
The CAC Payback Period tells you how many months it takes to recover your acquisition cost:
CAC Payback Period = CAC ÷ (ARPU × Gross Margin %)
Example: CAC of $500, ARPU of $80/month, gross margin of 75%:
CAC Payback Period = $500 ÷ ($80 × 0.75) = $500 ÷ $60 = 8.3 months
Benchmarks:
- Under 12 months: generally healthy
- Under 6 months: efficient
- Over 18 months: concerning - you're tying up significant capital in acquisition
A shorter payback period means your business is less dependent on external capital to fund growth. A payback under 12 months means each cohort of customers becomes self-funding within the year.
The LTV:CAC Ratio
The LTV:CAC ratio is the primary unit economics benchmark in SaaS:
LTV:CAC = LTV ÷ CAC
| Ratio | Interpretation |
|---|---|
| < 1:1 | Every customer destroys value |
| 1:1–3:1 | Marginal - acquisition costs too high relative to value |
| 3:1 | Healthy benchmark for SaaS |
| 5:1+ | Strong - consider accelerating growth investment |
Most SaaS investors look for 3:1 or better at scale. Early-stage companies often operate below this as they learn their best acquisition channels.
Why CAC Matters
It determines how much you can spend to grow. Your LTV sets the ceiling; CAC tells you whether you're under or over it. If LTV is $3,000 and CAC is $1,500, you have a 2:1 ratio - tight but workable. If CAC creeps to $3,000, you're breaking even on every customer before accounting for infrastructure and support costs.
It reveals which channels are actually working. Blended CAC hides channel-level inefficiency. A business might appear to have a healthy $400 blended CAC while one channel runs at $1,500 CAC and is quietly consuming most of the budget.
It's directly tied to your payback period. The longer you wait to recover acquisition costs, the more capital you need to sustain growth. Reducing CAC shortens payback and reduces the cash required to scale.
It informs pricing decisions. If your current pricing produces LTV that barely justifies your CAC, a pricing increase - even a modest one - can dramatically improve unit economics without necessarily affecting acquisition volume.
How to Reduce CAC
Invest in channels with compounding returns
Paid acquisition has a linear cost structure - spend stops, growth stops. Content, SEO, and community build assets that generate customers at declining marginal cost over time. Shifting mix toward these channels reduces blended CAC as the content library and domain authority compound.
Improve conversion rates
If your CAC is high because your conversion rate is low, improving the funnel is often more efficient than spending more. A/B testing landing pages, improving trial-to-paid conversion, and optimizing the sales process can all reduce effective CAC without cutting spend.
Build a referral motion
Referral customers cost a fraction of paid acquisition. Building a structured referral program - with incentives for both referrer and referred - can become a meaningful low-CAC acquisition channel at scale.
Target the segments with the best LTV:CAC
Not all customer segments have the same CAC. Focusing acquisition on segments that convert efficiently and retain well improves both sides of the ratio.
How to Track CAC
Chartsy calculates CAC and payback period from your Stripe or Paddle revenue data. You can ask:
- "What is my average customer acquisition cost this quarter?"
- "Show CAC payback period by plan"
- "What is my LTV:CAC ratio?"
- "How has CAC changed over the last 12 months?"
Connect Stripe and track your CAC →
Frequently Asked Questions About CAC
What is a good customer acquisition cost for SaaS? There's no universal answer - CAC is only meaningful relative to LTV. A CAC of $1,000 is excellent if LTV is $6,000 (6:1 ratio) and poor if LTV is $1,200 (1.2:1 ratio). The benchmark most investors use is a 3:1 LTV:CAC ratio, with a CAC payback period under 12 months.
What should be included in CAC calculation? A common mistake is only counting ad spend. Fully-loaded CAC includes all sales and marketing salaries, commissions, advertising spend, tools and software, agency fees, events, and affiliate costs - divided by new customers acquired in the same period. Excluding team costs significantly understates the true cost of acquiring a customer.
What is the difference between CAC and CPA? CPA (Cost Per Acquisition) typically refers to a single conversion event - a lead, a signup, or a click - and is used in advertising contexts. CAC refers to the cost of acquiring a paying customer and includes all sales and marketing costs. CPA is a channel-level metric; CAC is a business-level unit economics metric.
What is a good CAC payback period? Under 12 months is the widely cited benchmark for healthy SaaS unit economics. Under 6 months is excellent. Over 18 months means you're tying up significant capital in acquisition and are more dependent on external funding to sustain growth. In practice, faster payback means each cohort of customers becomes self-funding sooner.
How can I reduce customer acquisition cost? The highest-leverage approaches are: investing in content and SEO (compounding channels with declining marginal CAC over time), improving trial-to-paid conversion (more paying customers from the same traffic spend), building a referral program (customers acquired at near-zero incremental cost), and refining your ICP to target segments that convert faster and stay longer.
Related: What Is LTV? · What Is MRR? · What Is Churn Rate?
Written by
Chartsy TeamThe Chartsy Team writes guides, product updates, and resources to help SaaS and eCommerce founders make sense of their metrics, without SQL or spreadsheets.
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