Google ad KPIs: costs, conversions, and revenue

Google ad KPIs connect advertising spend to traffic, conversions, and attributed business value. Compare campaigns using the same dates, conversion actions, currency, and attribution settings, then calculate the ratios from their underlying totals. A campaign can attract inexpensive clicks while producing expensive sales outcomes.

Start with the decision and the export

A useful campaign review answers a specific question: where should the team investigate cost, conversion quality, or revenue before changing its budget? Select the measures that support that decision rather than treating every available column as a key performance indicator.

Export campaign ID, campaign name, reporting period, impressions, clicks, cost, conversions, and conversion value. Preserve the account currency and the settings that define which conversion actions enter the report. Use campaign IDs as keys because names can change.

For a B2B company, a conversion might be an inquiry, a qualified meeting, or a completed purchase. These are different business events. A marketing operations owner should record the selected event, while sales operations confirms whether it corresponds to the intended CRM outcome. Finance confirms whether the reported value represents sales, estimated lead value, or another measure.

Do not label every conversion value as revenue. Google's documentation explains that conversion values can be transaction-specific or a common value assigned to conversions. An assigned lead value is useful for a defined comparison, but it is not evidence that an invoice was issued.

Calculate the core measures consistently

The following definitions use clicks as the qualifying interactions because the worked example contains search campaigns measured on that basis.

Google defines CTR as clicks divided by impressions. Its conversion rate definition uses eligible ad interactions, which need not always be clicks. Keep the exported interaction basis when comparing different campaign formats.

Aggregate CPA = Total cost / total conversions

Aggregate ROAS = Total conversion value / total cost

Express CTR and conversion rate as percentages. Express CPC and CPA in dollars, and ROAS as a multiple. A zero denominator produces an undefined ratio; show that explicitly instead of displaying a reassuring zero.

A worked campaign review

Consider an illustrative US industrial supplier reviewing September 2026. All campaigns use USD and the same purchase conversion action. Here, conversion value is the recorded sales value attributed to that action, before deducting product and operating costs.

Apply the definitions to each row. Percentages, dollar ratios, and multiples below are rounded to two decimal places; calculations retain the underlying values.

The overall CPA is $12,000 / 250 = $48.00. Overall ROAS is $39,000 / $12,000 = 3.25x. Nonbrand Search has a $100.00 CPA because $6,000 / 60 = $100.00; its lower conversion rate and higher click cost both warrant investigation.

Prove the totals before interpreting them

The campaign costs must sum to the selected campaign report total: $2,400 + $6,000 + $3,600 = $12,000. Check clicks, impressions, conversions, and value in the same way. Exclude report subtotal rows when adding detail rows.

A second check reconstructs value from campaign spend and ROAS:

2,400 × 5.00 + 6,000 × 1.50 + 3,600 × 5.00 = 39,000

For CPA, divide total cost by total conversions rather than averaging campaign CPAs. The unweighted average of $24.00, $100.00, and $40.00 is $54.67, which does not describe the account's acquisition cost. The campaigns contribute different conversion volumes.

If transaction-level data is available, reconcile the attributed sales values to the eligible transaction list under the documented attribution rules. The advertising total need not equal the whole company ledger: organic sales, untracked transactions, returns, and different reporting dates can sit outside its scope.

Turn the review into owned decisions

Marketing owns the campaign investigation. For Nonbrand Search, inspect the search terms, landing page, and purchase records behind the result before cutting spend. Compare like audiences and purchase types; brand demand and new customer acquisition have different roles.

Sales operations owns the connection to qualified opportunities when the selected conversion is a lead. Finance owns the bridge from attributed sales to margin and recognized revenue. Use financial KPIs for the wider profitability review rather than asking ROAS to answer every financial question.

Keep the review distinct from a general metric versus KPI discussion. Decide which exception needs action, who will investigate it, and which later export will confirm the outcome. For another advertising source, Facebook ad KPIs covers its own measurement context.

Where it goes wrong

• Mixed conversion actions. Purchases and form submissions in one denominator make acquisition costs hard to interpret. Preserve action-level detail.
• Clicks assumed for every format. An interaction-based conversion rate may use a different denominator. Reconcile the actual basis before comparing rates.
• Assigned values called revenue. A standard lead value can support prioritization, but it does not become sales simply because it appears in a currency column.
• Incomplete outcomes. Recent clicks may produce later conversions. Record the export date and avoid declaring a campaign weak before its normal outcome window has elapsed.
• Advertising return treated as profit. ROAS leaves important business costs outside the calculation. Add a separate profitability review where the decision requires it.

Covirage is not affiliated with Google.

Review your own campaign file in Covirage

Bring a campaign export with its conversion definitions and a sample of your own transaction or CRM records where relevant. Covirage maps the columns, and its tools compute and check the supplied figures; the external AI model explains the results with every figure traced to its rows. Create a free Covirage account, then set up your business and bring a sample of your own export.

See revenue driver analysis for the supporting business context.