What is the allowable CPA / CPC calculator?
A free, browser-based calculator that works backward from your unit economics to the maximum CPA and CPC you can pay while staying profitable. Enter the margin you earn per conversion, the profit you want to keep, and your conversion rate(s) — and it returns your allowable (target) CPA and the highest CPC you should bid. It is the 'how much can I bid?' companion to the ad metrics calculator. Everything runs locally in your browser, so your numbers are never uploaded.
The formulas
- Allowable CPA = Margin per conversion − Target profit per conversion.
- Click → conversion rate (CVR) = the direct rate you enter, or Click→Lead rate × Lead→Conversion rate when you use the funnel inputs.
- Allowable CPC = Allowable CPA × CVR.
How to use it
- Enter the gross margin you earn from one conversion (revenue minus variable cost).
- Enter the profit you want to keep per conversion. Leave it blank for the breakeven ceiling.
- Enter your click → conversion rate, or split it into a click→lead and lead→conversion funnel.
- Read your allowable CPA and allowable CPC on the right — keep your actual bids below them.
Common use cases
- Setting a max CPA target before launching a paid search or social campaign.
- Deciding the highest CPC bid that still leaves room for profit.
- Checking whether your actual CPA (from the ad metrics tool) is under your allowable ceiling.