Google Ads Metrics in the Interface and API: Definitions, Formulas, and Limits
Understanding Google Ads Metrics
Google Ads metrics are the numerical signals that tell you whether your campaigns are working. Every dollar you spend, every impression served, every click recorded, and every conversion attributed flows into a reporting layer that Google exposes in both the Google Ads interface and the Google Ads API.
At a high level, Google Ads reporting separates metrics into two broad groups. The first group includes absolute metrics, such as impressions, clicks, cost, and conversions. The second group includes derived metrics, such as CTR, CPA, ROAS, and conversion rate. Both types are important, but they behave differently when you aggregate, segment, and compare data across dimensions.
This guide explains the core Google Ads metrics available in the interface and the API, how to interpret them, where they are limited, and why some metrics are unavailable for certain campaign types or segment combinations.
Important context: the guide below focuses on the core performance layer of Google Ads reporting. More advanced reporting areas, such as impression share, quality score components, video quartiles, auction insights, and store visits, are covered later in the article.
Basic Absolute Metrics
Absolute metrics are raw counts and sums accumulated over a reporting period. They describe what happened in the account directly, without being calculated from other metrics. In practice, these are the numbers you sum across campaigns, ad groups, keywords, ads, devices, and geographies.
The most important absolute metrics in Google Ads are impressions, clicks, cost, interactions, invalid clicks, conversions, all conversions, and conversion value.
Clicks and Interactions
Clicks and interactions are related, but they are not always the same thing.
API fields: metrics.clicks and metrics.interactions
A click is recorded when a user activates a link in your ad, for example by visiting a website, opening an app store page, or tapping the phone number button in a call-only ad. In Search, Display, Shopping, and many Performance Max contexts, clicks and interactions often match because clicking is the main available action.
An interaction is broader. It represents the primary engagement event for a specific ad format.
- Search ads: interaction = click
- Display ads: interaction = click
- Shopping ads: interaction = click
- Video ads, skippable in-stream: interaction = TrueView view, not a simple click
- Video ads, bumper and non-skippable: interaction = impression
- App campaigns: interaction can be a click or a view depending on the asset type
- Call-only ads: interaction = phone call initiated from the ad
- Responsive Display Ads with Lightbox: interaction = creative expansion
This distinction matters most in video reporting. For YouTube campaigns, metrics.interactions usually counts views rather than clicks. That means cost divided by interactions behaves like cost per view, not cost per click.
Important nuance: if your reporting pipeline labels metrics.interactions as “clicks” across all campaign types, your video reporting will be misleading. For mixed campaign dashboards, metrics.interactions is useful. For campaign-specific analysis, use the native field for that campaign type, such as metrics.clicks for Search and metrics.video_views for Video.
Segment restrictions: both metrics.clicks and metrics.interactions are broadly available across performance resources, but they are not available in the keyword_plan resource family because those resources use forecast and historical planning data rather than live performance data.
Cost
API field: metrics.cost_micros
Cost is the total amount spent on ad serving during the selected date range. It aggregates charges across pricing models, including CPC, CPM, CPV, and CPE.
In the Google Ads interface, cost is shown in the account currency. In the API, cost is returned in micros, which means millionths of the base currency unit. For example, a cost of $12.50 is returned as 12500000 in metrics.cost_micros.
Cost is one of the most universal metrics in Google Ads reporting. It is available across campaign types and works consistently across major dimensions like campaign, ad group, keyword, ad, device, audience, location, and time.
Important nuance: the cost shown in reporting is the actual charged amount, not the bid you entered or the target you configured in Smart Bidding.
Segment restrictions: cost is available across standard reporting segments. Segmenting does not change how cost is calculated. It only splits the same total across the selected dimension.
Impressions
API field: metrics.impressions
An impression is counted each time an ad is served in a place where it could potentially be seen. It is a serving event, not a confirmed view.
- Search: an impression is counted when your ad appears on a search results page
- Display: an impression is counted when the ad loads on a publisher page
- Video: an impression is counted when the video ad starts appearing
- Shopping: an impression is counted when the product card is displayed
- Performance Max: impressions roll up across Search, Display, YouTube, Gmail, Maps, and Discover
Impressions are available for all performance-bearing campaign types and resources.
Segment restriction: hotel campaigns use a different auction structure for impression share calculations. Impressions themselves are still reported, but impression share logic differs from standard campaigns.
Invalid Clicks and Invalid Click Rate
API fields: metrics.invalid_clicks and metrics.invalid_click_rate
Invalid clicks are click attempts that Google identifies as not representing genuine user interest. This may include automated bot activity, accidental repeat clicks, or traffic excluded by Google’s invalid traffic systems.
Invalid clicks are reported separately and are not included in metrics.clicks. This helps protect performance metrics such as CTR, CPC, and conversion rate from low-quality or filtered traffic.
Formula: invalid_click_rate = invalid_clicks / (clicks + invalid_clicks)
These metrics are most relevant for Search, Display, and Shopping. They are not generally available for Video and App campaigns, and they are only partially available for Performance Max.
Segment restrictions: invalid click metrics are not broadly available with conversion-action segmentation, conversion-type segmentation, or most audience segments. They are more reliably available when segmented by date, network, and device.
Conversions and All Conversions
API fields: metrics.conversions and metrics.all_conversions
In Google Ads, not every tracked conversion is treated the same way. Whether a conversion action appears in Conversions or only in All Conversions depends on its configuration in the account.
This distinction is critical because Smart Bidding strategies optimize against metrics.conversions, not against every tracked event in the account.
Case 1: the conversion action counts in Conversions when it is marked as a primary action, or “Include in Conversions.” These are the events that Smart Bidding uses for optimization.
Case 2: the conversion action counts in All Conversions but not in Conversions when it is marked as secondary, or “Exclude from Conversions.” These events are useful for analysis but do not guide automated bidding.
Case 3: the conversion action may appear in neither column if it is paused, removed, has no activity in the selected date range, or is not properly linked from its source, such as GA4.
Additional factors also affect the Conversions column, especially attribution model, conversion window, and whether you report by click date or conversion date.
Important nuance: metrics.conversions_by_conversion_date can be more useful than the default click-date view when you need period-over-period revenue or lead reporting based on when the conversion actually happened.
Both metrics.conversions and metrics.all_conversions are available across major campaign types, but their values depend heavily on conversion setup.
Conversion Value and All Conversion Value
API fields: metrics.conversions_value and metrics.all_conversions_value
Conversion value is the monetary value assigned to conversions. For ecommerce, it may reflect revenue. For lead generation, it may represent an estimated value per lead.
metrics.conversions_value includes the values of primary conversion actions, while metrics.all_conversions_value includes values from all tracked conversion actions, including secondary, view-through, and cross-device conversions.
Conversion value only becomes meaningful when values are configured correctly. If values are missing, reported conversion value may stay at zero even when conversion volume exists.
Practical note: for ecommerce, conversion value is the basis for ROAS analysis. For lead generation, advertisers often focus more on conversion volume and cost per conversion unless lead values are modeled with reasonable accuracy.
Relative and Rate Metrics
Relative metrics are ratios built from absolute metrics. They help explain efficiency, quality, and outcome rate rather than raw volume. Because they are ratios, they should not be summed or averaged blindly across rows. In most cases, the correct method is to sum the base metrics first and only then recalculate the rate.
CTR, Click-Through Rate
API field: metrics.ctr
Formula: clicks / impressions
CTR shows how often users click after seeing your ad. In the API it is returned as a decimal, while in the interface it is displayed as a percentage.
CTR is one of the most common signals for ad relevance and creative strength, but it varies dramatically by campaign type. Branded Search can have very high CTR, while Display often has much lower rates.
For video campaigns, CTR is not the primary engagement signal. In that context, view rate is usually more meaningful.
Interpretation note: for call-only campaigns, CTR behaves more like a call rate than a standard website click-through rate.
Interaction Rate
API field: metrics.interaction_rate
Formula: interactions / impressions
Interaction rate generalizes CTR across campaign types. For Search and Display it usually equals CTR. For Video it behaves like view rate. For call-focused formats it can reflect call initiation rate.
If you need one engagement-rate column for a mixed campaign dashboard, metrics.interaction_rate is often a better choice than metrics.ctr.
Invalid Click Rate
API field: metrics.invalid_click_rate
Formula: invalid_clicks / (clicks + invalid_clicks)
This metric shows the share of total click attempts that Google filtered as invalid before billing or counting them in standard click totals.
It is useful for traffic quality review, especially when comparing networks, placements, or account areas that may be attracting lower-quality traffic.
Conversion Rate
API field: metrics.conversions_from_interactions_rate
Formula: conversions / interactions
Conversion rate measures how efficiently interactions turn into primary conversions. In many campaigns this is effectively conversions per click, but the metric uses interactions in the denominator, which makes it more flexible across campaign types.
Conversion rate is influenced by audience intent, landing page experience, offer quality, site speed, and the conversion actions you chose to count as primary.
The all-conversions variant is available via metrics.all_conversions_from_interactions_rate.
Value per Conversion, Average Order Value
API field: metrics.value_per_conversion
Formula: conversions_value / conversions
Value per conversion shows the average monetary value of one conversion. For ecommerce this often behaves like average order value. For lead gen it may reflect modeled lead value.
This metric is useful when conversion quality shifts over time, for example when product mix changes or when attribution model changes redistribute value across touchpoints.
The broader variant is metrics.all_value_per_conversion.
Cost-Based Efficiency Metrics
Cost-based metrics express how much you pay for a given result. They are central to campaign optimization because they connect spend to outcomes such as clicks, views, conversions, and conversion value.
In the Google Ads API, monetary cost fields are generally returned in micros. Divide by 1,000,000 to get the value in the account currency.
Average CPC
API field: metrics.average_cpc
Formula: cost / clicks
Average CPC is the average amount paid per click. It is especially important in Search and Shopping because these formats are strongly click-driven.
Average CPC is less useful for billing models centered on impressions or views. In YouTube campaigns, for example, Average CPV is often the more relevant efficiency metric.
Average CPM
API field: metrics.average_cpm
Formula: (cost / impressions) * 1000
Average CPM measures the cost per thousand impressions. It is most relevant for awareness and reach-oriented campaigns, especially Display and Video.
Search and Shopping may technically surface CPM-related values in some reporting contexts, but CPM is usually not the core optimization metric for those campaign types.
Average CPV
API field: metrics.average_cpv
Formula: cost / video_views
Average CPV is the average amount paid per video view in campaigns that use CPV billing. It is mainly a Video metric and is not generally available or meaningful outside video-driven campaign types.
Note: Google renamed the Views metric to TrueView Views in the interface in late 2025, but the underlying API field metrics.video_views and the CPV logic did not change.
Cost per Conversion, CPA
API field: metrics.cost_per_conversion
Formula: cost / conversions
CPA is the average amount spent to generate one primary conversion. It is one of the main efficiency metrics for direct response advertising and is central to Smart Bidding strategies like Target CPA.
Because it uses metrics.conversions, CPA reflects only primary conversion actions.
Conversion Value per Cost, ROAS
API field: metrics.conversions_value_per_cost
Formula: conversions_value / cost
ROAS measures how much conversion value is generated for each unit of ad spend. It is especially important for ecommerce accounts that pass accurate revenue values.
The broader variant, metrics.all_conversions_value_per_cost, includes additional conversion types such as secondary and view-through conversions.
Important nuance: ROAS is only trustworthy when conversion values are configured properly. If values are zero, incomplete, or arbitrary, the metric becomes weak for decision-making.
Average Cost per Interaction
API field: metrics.average_cost
Formula: cost / interactions
Average cost per interaction is the cross-campaign-type efficiency metric. In Search it behaves like average CPC. In Video it behaves like average CPV. In call-driven campaigns it behaves like cost per call.
For blended dashboards that combine campaign types, this metric is often more consistent than average CPC.
Metric Availability by Campaign Type
The table below summarizes how core Google Ads metrics behave across major campaign types. In this context:
- Available means the metric is supported and meaningful
- Not available means the metric is structurally excluded or not relevant
- Partial means the metric may be returned in limited scopes or only under certain conditions
| Metric | Search | Display | Video | Shopping | PMax | App | Demand Gen | Smart |
|---|---|---|---|---|---|---|---|---|
| Impressions | Available | Available | Available | Available | Available | Available | Available | Available |
| Clicks | Available | Available | Partial | Available | Available | Available | Available | Available |
| Cost | Available | Available | Available | Available | Available | Available | Available | Available |
| CTR | Available | Available | Partial | Available | Available | Available | Available | Available |
| Interactions | Available | Available | Available | Available | Available | Available | Available | Available |
| Interaction Rate | Available | Available | Available | Available | Available | Available | Available | Available |
| Invalid Clicks | Available | Available | Not available | Available | Partial | Not available | Not available | Not available |
| Invalid Click Rate | Available | Available | Not available | Available | Partial | Not available | Not available | Not available |
| Conversions | Available | Available | Available | Available | Available | Available | Available | Available |
| All Conversions | Available | Available | Available | Available | Available | Available | Available | Available |
| Conversion Value | Available | Available | Available | Available | Available | Available | Available | Available |
| All Conv. Value | Available | Available | Available | Available | Available | Available | Available | Available |
| Avg. CPC | Available | Available | Partial | Available | Available | Available | Available | Available |
| Avg. CPM | Not available | Available | Available | Not available | Available | Available | Available | Partial |
| Avg. CPV | Not available | Not available | Available | Not available | Not available | Not available | Not available | Not available |
| Cost / Conv. (CPA) | Available | Available | Available | Available | Available | Available | Available | Available |
| Conv. Value / Cost (ROAS) | Available | Available | Available | Available | Available | Available | Available | Available |
| Conv. Rate | Available | Available | Available | Available | Available | Available | Available | Available |
| Value / Conv. (AOV) | Available | Available | Available | Available | Available | Available | Available | Available |
| View-through Conv. | Not available | Available | Available | Not available | Available | Available | Available | Partial |
| Cross-device Conv. | Available | Available | Available | Available | Available | Not available | Available | Available |
| Phone Calls | Available | Not available | Not available | Not available | Partial | Not available | Not available | Available |
Notes on “Partial” entries in the table above:
- Clicks, Video: clicks exist for video campaigns, for example CTA overlay clicks, but the main engagement signal is usually
metrics.video_views. - Average CPM, Smart Campaigns: Smart Campaigns may surface CPM-like values in Display contexts, but the metric has limited optimization value because advertisers do not manage CPM bidding directly there.
- Invalid Clicks, Performance Max: usually available at campaign level, but not consistently available at lower or more segmented levels.
- View-through Conversions, Performance Max: available for Display and YouTube activity inside PMax, but not for Search channel impressions.
- Phone Calls, Performance Max: available only when phone call assets are present and call tracking is enabled.
- Store Visits, Video: available only for eligible accounts and campaign types tied to physical locations with sufficient volume.
Beyond Core Metrics
The metrics above form the core reporting layer in Google Ads. Once those are understood, the next step is to work with more specialized diagnostic and competitive signals that explain why campaigns are winning or losing opportunities.
Impression Share and Competitive Visibility
Impression share metrics help explain how much of the available auction traffic you capture and how much you lose due to budget or rank. Key API fields include metrics.search_impression_share, metrics.search_budget_lost_impression_share, metrics.search_rank_lost_impression_share, metrics.search_absolute_top_impression_share, and Display equivalents such as metrics.content_impression_share.
Quality Score Components
Quality diagnostics include metrics.historical_quality_score, metrics.historical_creative_quality_score, metrics.historical_expected_ctr, and metrics.historical_landing_page_quality_score. These are especially useful at keyword level and are some of the most actionable signals for improving Search performance.
Video Engagement Metrics
Video-specific reporting goes beyond views. Metrics such as metrics.video_quartile_p25_rate, metrics.video_quartile_p50_rate, metrics.video_quartile_p75_rate, metrics.video_quartile_p100_rate, and metrics.video_view_rate help explain where users disengage and how compelling the creative is.
Prominence and Positioning Metrics
Metrics such as metrics.top_impression_percentage and metrics.absolute_top_impression_percentage show how often ads appeared in premium positions on the search results page.
Store Visit Attribution
metrics.store_visits_count estimates how many users later visited a physical store after seeing or clicking an ad. This metric is powerful for offline businesses, but it requires enough eligible traffic and the right account setup.
Lead and Asset-Level Metrics
Additional lead-focused and asset-level metrics, such as metrics.lead_cost_micros and metrics.lead_conversions, add depth for Demand Gen and lead capture workflows.
Auction Insights
Auction insights metrics provide competitive context, including impression share, overlap rate, outranking share, position above rate, top of page rate, and absolute top of page rate relative to other advertisers who appeared in the same auctions.
Final takeaway: the core Google Ads metrics tell you what happened. Advanced metrics help explain why it happened. Used together, they give a much more reliable foundation for optimization, reporting, and automated analysis.