# CPA vs CAC

> CPA is ad spend per action on one platform. CAC is the full cost of winning a new customer. A side-by-side table, a worked example in rupees, and which to track.
- **Author**: Marxx
- **Published**: 2026-11-05
- **Category**: Metrics
- **URL**: https://marxx.ai/library-compare/cpa-vs-cac

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CPA is what you pay in ads for one action, such as a purchase or a sign-up, on one platform. CAC is the full cost of winning one new customer, across every channel, including agency fees, tools and salaries. Use CPA to run your ads each day. Use CAC to judge whether the business grows at a price it can afford.

## Side by side

| | CPA (cost per acquisition) | CAC (customer acquisition cost) |
|---|---|---|
| Counts | One action: purchase, lead, install | One new customer |
| Cost included | Ad spend, usually one platform | All sales and marketing cost |
| Repeat buyers | Included in the action count | Left out. New customers only |
| Where you read it | Ads Manager or Google Ads | Your own sheet or finance data |
| Used for | Daily ad decisions | Business health, with lifetime value |

## A worked example

Say a D2C brand has this month.

**Meta report:** INR 2,00,000 spent, 400 purchases.
- CPA = 2,00,000 / 400 = **INR 500**

Of those 400 purchases, 150 came from repeat buyers. So Meta brought 250 new customers.

**Other channels and costs:**
- Google ads INR 70,000, which won 40 new customers
- Agency INR 50,000
- Tools INR 20,000
- Creator payments INR 30,000

**Total cost:** 2,00,000 + 70,000 + 50,000 + 20,000 + 30,000 = INR 3,70,000
**New customers:** 250 + 40 = 290

- CAC = 3,70,000 / 290 = about **INR 1,276**

Meta says INR 500. The business paid INR 1,276 to win each new customer. Both numbers are right. They answer different questions.

## What goes into CAC

Keep the same list every month. A full CAC usually counts:

- Ad spend on every platform
- Agency and freelancer fees
- Creator and influencer payments
- Marketing tools and software
- The marketing team's salaries

## Which to track

- **Judging one ad or ad set:** CPA. It is fast and sits in your ad account.
- **Setting a budget or a price:** CAC. Compare it with what a customer is worth over time, as in the [LTV to CAC ratio](/glossary/ltv-to-cac-ratio).
- **Cash planning:** CAC with the [CAC payback period](/glossary/cac-payback-period), which says how long a customer takes to repay it.

When each platform claims credit for the same buyers, add a blended view. See [ROAS vs MER](/compare/roas-vs-mer).

For the formulas and more examples, see [what CPA is](/glossary/cpa) and [what CAC is](/glossary/cac).

## Common mistakes

- Calling Meta's cost per result your CAC. It leaves out other channels and cost, and it counts repeat buyers.
- Changing what you include in CAC from month to month. Pick a definition and keep it.
- Setting a target CPA from CAC alone. Set it from profit per order, then check against CAC.

## FAQ

### Is CAC always higher than CPA?

Usually, because CAC adds more cost. But CAC averages over every channel, so it can sit below one platform's CPA if other channels win customers cheaply.

### Is CAC only for new customers?

Yes. Counting repeat buyers makes CAC look lower than it is.

### What is a good CPA?

One below your profit per order. See [what CPA is](/glossary/cpa) for how to set a target.

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