What you spent on the campaign or ad set in the period.
Purchases, sign-ups or leads, whichever action you pay to get.
CPA
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Enter ad spend and conversions.
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The CPA formula
CPA = ad spend ÷ conversions
Example: You spend $500 and get 40 sales: $500 ÷ 40 = $12.50 per sale. To get 100 sales at the same CPA, budget $12.50 × 100 = $1,250.
What is CPA?
CPA tells you what each result costs. It is the number to hold against what a customer is worth: if a sale leaves you $30 of margin, a $12.50 CPA is profitable and a $40 CPA is not.
Ad platforms report CPA for the conversions they track, so define the conversion first. A cost per lead is not a cost per customer, and each platform counts the conversions it can attribute to itself.
What is a good CPA?
It depends on the channel, the campaign objective and what you sell, so compare against your own history first. For scale, these are the typical figures from the largest recent studies of ad accounts and shops.
| Where | Typical | Source |
|---|---|---|
| Google search ads, cost per lead, US From $26.84 (arts and entertainment) to $131.63 (legal) | $66.69 | WordStream, 2026 Google Ads Benchmarks |
| Meta, cost per lead, US From $12.30 to $61.56 by industry | $27.39 | WordStream, 2026 Facebook Ads Benchmarks |
| Meta, cost per purchase, ecommerce brands Aug 2025 to Jul 2026 | $38.99 | Triple Whale, Facebook ad benchmarks (2026) |
| TikTok, cost per purchase, ecommerce brands Aug 2025 to Jul 2026 | $17.07 | Triple Whale, TikTok benchmarks (2026) |
How to lower your CPA
- Raise the landing page's conversion rate: the same clicks then bring more results.
- Move budget from campaigns, audiences and keywords with a high CPA to those with a low one.
- Cut placements and searches that bring clicks but no conversions.
- Check what a customer is worth. Your maximum CPA is the margin a customer brings; above that, each sale loses money.
What CPA doesn't tell you
- Each ad platform counts the conversions it can attribute to itself, so the platforms' CPAs often add up to more conversions than you actually had.
- CPA treats every conversion the same. A customer who comes back for years is worth more than one who buys once.
OneLence helps marketing teams find growth opportunities, know what to do next, and grow more efficiently without simply spending more. It puts ads, search, AI assistants and affiliate partners side by side, with the visitors and sales each one brings, and says where to invest, hold or cut back. See how it works.
Frequently asked questions
How do you calculate CPA?
Divide ad spend by the number of conversions. $500 for 40 sales is $500 ÷ 40 = $12.50 per sale.
What is the difference between CPA and CAC?
CPA is the cost of one conversion from ads, which can be a lead or a sign-up. CAC, customer acquisition cost, is all sales and marketing cost divided by new paying customers.
What is a good CPA?
One below what a customer is worth to you. Work out your margin per sale, or per customer over their lifetime, and keep CPA under it. For scale, the 2026 medians were $66.69 per lead on Google search ads and $27.39 per lead on Meta in the US, and $38.99 per purchase on Meta for ecommerce brands.
How do you calculate CPA from CPC and conversion rate?
CPA = CPC ÷ conversion rate. A $0.50 CPC with a 2% conversion rate gives $0.50 ÷ 0.02 = $25 per conversion.
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