Measuring reach and frequency

Beginning August 2020, we're removing cookie-based reach metrics from Google Ads. Unique reach metrics will replace cookie-based reach metrics as the primary method for reach measurement. Cookie-based reach metrics also won't show reporting data if the end date is after July 31, 2019.

By analyzing reach and frequency data for display and video campaigns, you can better understand how many people were shown your ads and how frequently the same people were shown them over a certain period of time. Whether you’d like to focus on reinforcing a message or on reaching new people, this information can help you get a clearer picture of how you’re meeting your reach goals.

Reach and frequency metrics

Unique reach

Unique reach metrics measure the total number of people who were shown an ad.  These metrics go beyond basic cookie measurements to help you understand how many times people were shown your ad across different devices, formats, and networks.

These days, people are often on the go and use multiple devices throughout the day. Our unique reach models measure the total reach of an ad by accounting for cases when people may see the same ad on different devices or when multiple people share the same device.

Unique reach metrics include:

  • Unique users
  • Avg. impr. freq. per user
  • Avg. impr. freq. per user (7 days)
  • Avg. impr. freq. per user (30 days)

Cookie-based reach

In addition to “unique reach” metrics, you can also view reach metrics that are based on cookies. Cookies enable us to estimate reach because they distinguish individual browsers. For cookie-based reach, Google Ads counts the number of cookies that have been served an ad or recorded a click on an ad. This measure is an estimate because some people use more than one browser or computer which have different cookies, so they may be counted more than once. Cookie-based metrics can be helpful if you’re using frequency capping, since frequency caps are  applied to cookies, not unique users.

Cookie-based reach metrics include:

  • Unique cookies
  • Avg. impr. freq. per cookie
  • Unique viewers (cookies)
  • Avg. view freq. per cookie

See reach and frequency data

You can view reach and frequency data by adding the columns for these metrics to your statistics table, and selecting a specific time period in the dropdown menu. These columns, found under "Reach metrics," are only available when you’re on  the Campaigns page.

Learn how to add or remove columns

How Google calculates reach

How unique reach is calculated

To calculate unique reach, Google Ads uses statistical models that account for user behavior across many browsers and devices. These models are created by observing aggregated user behavior across Google products to determine cross-device usage patterns. Google Ads combines behavior observations with other signals and local inputs (such as census and Google-Gallup surveys) to deduplicate an audience across sessions, formats, networks, and devices. The result is the number of unique users (not cookies) who saw an ad.

How cookie-based reach is calculated

When people browse the Display Network, Google may store a cookie in their web browser, which helps determine ad impressions. However, some ad impressions may not be associated with a cookie, due to people’s browser settings or other factors. Our system calculates cookie reach by first deduplicating cookies and counting the number of unique cookies.  For impressions that did not have a cookie, we use a statistical model to estimate the number of cookies that were likely to be reached, and add this to the total cookie reach.

Reach and user privacy

Important: Our methodology aggregates all users and cookies and requires that a minimum number of users is reached before any data is reported to advertisers. Personally identifiable information is never used.

Why you may not see reach metrics

Most reach metrics can only be reported for a date range of 92 days or less. You may not see reach data in your table if you’ve selected a date range that’s longer than 92 days.

If you’re looking at the frequency distribution of a campaign, you can only see data in your table if the date range is 31 days or less.

Reach metrics may not immediately show data for some campaigns and reporting segments, depending on a few factors, including the availability of data by country and whether your ad has reached a minimum threshold of impressions and unique users. Cookie reach data may be available when unique reach data isn’t. This is because unique reach models don’t support every country and also need to meet certain impression minimums.

Accounting for reporting delay

Due to the modeling involved in our calculations, it typically takes up to 3 days for reach metrics to be available in your account. Keep this delay in mind if your date range includes the last few days.

For example, if your date range is set to “Last 7 days,” consider that data from the last 3 days may not be complete. So the numbers shown for the last 7 days may not include the most recent 3 days of the last 7 days.

About reach and location targeting

Unique reach metrics use statistical models based on observing aggregated user behavior at the country level. Because the models are calculated at the country level, in a small percentage of cases the metrics may appear inconsistent, particularly for campaigns that target small geographical areas, such as a single city or zip code.

In other cases, a large volume of temporary visitors to a particular location may make unique reach appear inflated. We provide our best estimates of unique reach for these cases and we’re continuously working to improve our models to provide more precise location estimates.

Frequency capping and viewable impressions

For Display campaigns, only impressions that were viewable count towards frequency caps. The “Avg. impr. freq. per cookie” and other frequency reporting data may look higher than your frequency caps, because it is counting both viewable and unviewable impressions. 

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