📈 Business & Marketing

Cost Per Acquisition (CPA) Calculator

Calculate Cost Per Acquisition for any paid channel. Free CPA calculator for US digital marketers and growth teams.

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What This Calculator Tells You

Cost per acquisition (CPA) is what you pay in advertising for each conversion — a sign-up, lead, sale or install, whichever action you are optimizing for. It is the core efficiency number for paid campaigns on Google, Meta, LinkedIn and other platforms.

CPA = total ad spend ÷ conversions.

What to Enter

Total ad spend ($) — what you spent on the campaign, ad set or channel in the period. Most teams use media spend only; add agency fees if you want a fully loaded CPA.
Conversions / acquisitions — the number of the specific action you are measuring in the same period. Use one definition consistently (for example, completed sign-ups, not form starts).

Worked Examples

1. A Google Ads sign-up campaign

$4,500 spent in a month brings in 90 free-trial sign-ups.

Enter $4,500 and 90 → CPA $50 per sign-up.

2. A cheaper channel — or just cheaper leads?

Meta ads cost $3,000 for 150 leads.

Enter $3,000 and 150 → CPA $20 per lead.
Meta looks 2.5× cheaper, but if 30% of Google sign-ups become customers and only 5% of Meta leads do, the cost per customer is about $167 on Google versus $400 on Meta.

3. A campaign with no conversions yet

$1,200 spent, zero conversions recorded.

The calculator does not return a CPA, because you cannot divide by zero. Check conversion tracking first, then decide whether the campaign needs more time or should be paused.

How It’s Calculated

CPA = Total Ad Spend ÷ Number of Acquisitions (paying customers).

CPA: Cost per Acquisition

How to Read Your Result

Compare against a target CPA. Work backwards from what a conversion is worth: if 20% of trials become customers worth $600 in gross profit, a trial is worth about $120, so a $50 CPA leaves room to scale.
Compare channels on the same action. CPA for a lead and CPA for a sale are different metrics.
Move from CPA to CAC. To see the full cost of winning a paying customer, including salaries and tools, use the CAC calculator, and compare it with customer lifetime value.

Common Mistakes to Avoid

Comparing CPAs for different actions. A $20 lead and a $50 purchase are not comparable.
Optimizing for the cheapest CPA only. Cheap conversions are often low-quality ones. Track what happens after the conversion.
Trusting platform-reported conversions blindly. Ad platforms can each claim the same conversion. Check against your own analytics or CRM.
Judging too early. With only a handful of conversions, CPA swings wildly from day to day.

Built and maintained by GenAlpha Tools Editorial. Formula tested against known answers and edge cases · last reviewed October 2026. How we calculate · Report an error

When to Use This Calculator

Compare campaigns, ad sets and channels.
Set bid targets and daily budgets.
Report paid-media efficiency to clients or managers.
Decide when to pause or scale a campaign.

Frequently Asked Questions

What is the difference between CPA and CAC?

CPA is usually ad spend per conversion action (which might be a lead or trial). CAC is the total sales and marketing cost per new paying customer. See the CAC calculator.

What is a good CPA?

One that is comfortably below what the conversion is worth to you. A $100 CPA can be great for a $2,000 product and terrible for a $50 one.

What is the difference between CPA and CPL?

CPL (cost per lead) is a CPA where the action is a lead. Use the cost per lead calculator for lead-generation campaigns.

Should I include agency fees?

For comparing ad platforms, media spend alone is standard. For judging true profitability, include fees and creative costs.

Do you store the values I enter?

No. All calculations happen in your browser. Your data never leaves your device.

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