CPA Calculator

What is CPA?

CPA stands for cost per acquisition — the amount you spend, on average, to earn one conversion. That conversion could be a purchase, a signup, a lead, or any other action you're optimizing for. CPA is one of the clearest ways to judge whether a campaign is actually paying off, since it ties spend directly to outcomes instead of clicks or impressions.

Worked example: a campaign spends $1,000 and drives 40 conversions. CPA = 1000 ÷ 40 = $25.00. You can also derive CPA from CPC and conversion rate: a $2 CPC with a 5% conversion rate gives CPA = 2 ÷ (5 ÷ 100) = $40.00.

FAQ

What's a good CPA?

It depends entirely on your margins and customer lifetime value — there's no universal benchmark. A useful gut check: your CPA should leave enough margin after the sale to be profitable, or be justified by strong repeat purchase or subscription revenue. Compare your CPA to your average order value or customer LTV, not to an industry average alone.

CPA vs CAC — what's the difference?

CPA (cost per acquisition) is the cost of a single conversion or action within one campaign or channel — a signup, a lead, a purchase. CAC (customer acquisition cost) is the fully-loaded cost to acquire one paying customer, and typically rolls in more cost categories: sales team salaries, tooling, overhead, and blended spend across every channel, not just ads. CPA is a campaign-level metric; CAC is a business-level metric.

How do I lower my CPA?

Lower your CPC (better Quality Score, tighter targeting, stronger ad copy), or raise your conversion rate (clearer landing pages, less friction in the signup/checkout flow, better offer-to-audience match), since CPA is a function of both. Cutting wasted spend on underperforming keywords, placements, or audiences also brings blended CPA down fast.