CAC (Customer Acquisition Cost)

What Is CAC?

Customer Acquisition Cost measures the all-in cost of getting one new customer. Unlike CPA, which typically looks at a single campaign or channel, CAC accounts for every dollar you spend on marketing:

CAC = Total Marketing & Sales Costs / Number of New Customers

If you spend $10,000 total on ads, email tools, design, agency fees, and attribution software in a month, and you acquire 200 new customers, your CAC is $50.

CAC vs CPA: The Key Difference

The distinction matters more than most merchants realize:

	CPA	CAC
Scope	Single campaign or channel	All marketing and sales
Includes	Ad spend only	Ad spend + tools + salaries + overhead
Use case	Optimize individual campaigns	Evaluate overall business health
Example	”$18 per customer from Meta Ads"	"$42 per new customer, all channels”

Your Meta CPA might look great at $18, but if you are also paying for Google Ads, Klaviyo, an agency, a designer, and various SaaS tools, your real CAC is likely 2-3x higher.

How to Calculate CAC for a Shopify Store

Include all of these costs in your calculation:

1. Paid advertising: Meta, Google, TikTok, Pinterest, Snapchat
2. Marketing software: Email platform, SMS tools, attribution tools, analytics
3. Creative costs: Designers, video editors, photographers
4. Agency or consultant fees: If you outsource any marketing
5. Content creation: Blog writing, social media management
6. Team costs: Salary portion of anyone doing marketing work

Divide the total by the number of new customers only. Repeat purchases from existing customers should not count, because you already acquired those customers.

What Is a Good CAC?

The benchmark that matters most is the ratio of LTV to CAC:

• LTV:CAC of 3:1 or higher: Healthy and sustainable business
• LTV:CAC of 2:1: Viable but may struggle with cash flow
• LTV:CAC of 1:1 or lower: Unsustainable unless you are deliberately investing in growth

If your average customer spends $120 over their lifetime and your CAC is $40, your LTV:CAC ratio is 3:1. That is a healthy business.

How to Reduce CAC

• Improve conversion rates: Better product pages, faster site speed, and streamlined checkout reduce CAC without spending more on ads.
• Increase organic traffic: SEO and content marketing bring in customers at near-zero marginal cost.
• Optimize paid channels: Use UTM tracking to identify your lowest-CPA channels and shift budget toward them.
• Build referral programs: Existing customers acquiring new customers dramatically lowers blended CAC.
• Improve retention: A higher LTV makes a higher CAC acceptable.

CAC in Detectly

Detectly shows you the true cost of acquisition by channel by matching actual Shopify orders to their marketing sources. This gives you the data you need to calculate accurate channel-level CPA and overall CAC, based on real revenue rather than platform-estimated conversions.