Ad metrics calculator: CTR, CPC, CPM, CPA, conversion rate and ROAS
Ad reports are full of abbreviations. Most come from four numbers you already have: how much you spent, how many times the ad was shown, how many people clicked, and how many took the action you wanted. Enter them below and the calculator works out the rest.
Nothing leaves your browser. The starting values are examples.
The formulas, in plain terms
| Metric | Formula | What it tells you |
|---|---|---|
| Click-through rate (CTR) | clicks / impressions | How often people who saw the ad chose to click |
| Cost per click (CPC) | spend / clicks | The average price of a visit |
| Cost per thousand (CPM) | spend / impressions x 1,000 | The price of being shown 1,000 times |
| Conversion rate | conversions / clicks | How many visits turn into the action you want |
| Cost per conversion (CPA) | spend / conversions | What each lead or sale costs |
| Return on ad spend (ROAS) | revenue / spend | Revenue for each dollar of ad spend |
How to read them together
No single metric tells the whole story. A high click-through rate with a low conversion rate often means the ad promises something the page does not deliver. A low cost per click with a high cost per conversion means you are paying for visits that do not act. Return on ad spend looks at revenue, not profit, so also compare it with your margin before deciding it is good.
Browse the glossary for any term you do not recognize, or read how an ad auction works to see why costs move.
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