Work out your cost per acquisition from ad spend and conversions, or find the most you can afford to pay for a customer and still make a profit.
Built and maintained by the Kadima team. Updated September 2026.
Works in any currency. Enter every amount in the same one.
Use the same date range for both. The calculator shows your cost per acquisition straight away.
Optional. Adding clicks and revenue per conversion gives you cost per click, conversion rate and ROAS.
Switch to the second tab to find the CPA you can afford, based on customer value and margin.
CPA = total ad spend ÷ number of conversions. If you spend $2,500 and get 50 sales, your CPA is $50. A conversion is whatever action you count as a win: a sale, a lead form, a booked call or a sign-up.
Your CPA only means something next to what a customer is worth. Break-even CPA = customer value × gross margin. If a customer is worth $120 and your gross margin is 60%, you can pay up to $72 and break even. To keep a 20% profit, your target CPA is $120 × 40% = $48.
Multiply your target CPA by your lead-to-customer rate. If one in four leads becomes a customer, a $48 target CPA means you can pay up to $12 per lead.
Tighten your keywords and add negatives (our keyword wrapper helps), make sure each ad leads to a page that matches its promise, and fix slow or confusing landing pages. A small rise in conversion rate cuts CPA faster than most bid changes.
Sources: Google Ads Help: about Target CPA bidding, Google Ads Help: about conversion measurement, Google Ads Help: about Target ROAS bidding.
A good CPA is any CPA below your target, the most you can pay per customer and still make the profit you want. Industry averages vary widely and ignore your margins, so they make poor benchmarks.
CPC is what you pay per click. CPA is what you pay per conversion. They are linked by conversion rate: CPA equals CPC divided by conversion rate, so a $2 click that converts 4% of the time gives a $50 CPA.
Use lifetime value if customers reliably buy again and you can afford to wait for that revenue. If cash flow is tight or you lack repeat purchase data, base it on the first order.
The usual causes are more competition in the auction, broader keywords pulling in weaker traffic, tracking changes, a slower or changed landing page, and ad fatigue. Check tracking first, then search terms, then the landing page.
Cost per lead is a type of CPA where the conversion is a lead. If you sell through leads, track both cost per lead and cost per customer, because cheap leads that never buy can hide an expensive CPA.
Our PPC team builds and runs Google Ads and paid search campaigns around your real margins, not click-through rates.
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