KeySendGoogle Ads metric calculator: CTR, CPC, CPA and ROAS
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Enter five totals from one Google Ads report and the calculator returns CTR, average CPC, cost per conversion and ROAS. It uses the same formulas as the CTR, Avg. CPC, Cost / conv. and Conv. value / cost columns, so you can check a spreadsheet or rebuild a combined total.
The formulas the calculator uses
Google Ads shows Conv. value / cost as a ratio, for example 4.00. Target ROAS bid strategies use the same ratio as a percentage, so 4.00 is a target ROAS of 400%. The calculator shows the ratio.
Google defines Avg. CPC as the total cost of your clicks divided by the number of clicks. On Search campaigns that charge per click, cost and the cost of clicks are the same number. If a campaign also pays for views or impressions, total cost divided by clicks will not match the Avg. CPC column.
| Result | Formula | Google Ads column |
|---|---|---|
| Click-through rate (%) | Clicks ÷ impressions × 100 | CTR |
| Average CPC | Ad spend ÷ clicks | Avg. CPC |
| Cost per conversion | Ad spend ÷ conversions | Cost / conv. |
| ROAS | Conversion value ÷ ad spend | Conv. value / cost |
Worked example
The form below starts with hypothetical values: 1,000 in ad spend, 20,000 impressions, 1,000 clicks, 40 conversions and 4,000 in conversion value. The results are a CTR of 5%, an average CPC of 1, a cost per conversion of 25 and a ROAS of 4. In Google Ads that ROAS would show as 4.00 in the Conv. value / cost column.
Combine campaigns by adding totals first
To get one figure for several campaigns, add their spend, clicks, conversions and value, then calculate once. Do not average the campaign ratios.
Hypothetical example: Campaign A spends 600 on 800 clicks (Avg. CPC 0.75). Campaign B spends 400 on 200 clicks (Avg. CPC 2.00). The simple average of the two CPCs is 1.375. The real account figure is 1,000 ÷ 1,000 = 1.00, because Campaign A bought four times as many clicks. The same rule applies to CTR, cost per conversion and ROAS.
Before you trust the result
- Take all five numbers from the same date range, the same account and the same currency.
- Take conversions and conversion value from the same column. The Conversions column counts primary conversion actions. All conv. adds secondary actions, view-through conversions and other sources, so mixing the two gives a ratio that matches no Google Ads column.
- Decimals are accepted because attribution can give fractional conversions, such as 12.5.
- If a denominator is zero, the result is shown as undefined. A campaign with spend and no conversions has no cost per conversion. Report the spend and the zero conversions instead of a cost of 0.
- Conversion value is the value your account sends or assigns. It can be revenue, an estimated lead value, or another number. ROAS is not profit, because it leaves out product costs and fees.
- Conversion rate is not in this calculator. Google divides conversions by the ad interactions that can be tracked to a conversion, which are not always clicks.
Compare two periods
To see how one of these results changed from one period to the next, use the period comparison calculator. It gives the absolute change, the percent change and, for rates such as CTR, the change in percentage points.
Calculate with your figures
The calculator code runs in your browser and does not send its inputs to a server.
