Reach reports

See the number of unique visitors

Reach reports display the number of unique visitors exposed to different advertisers, orders, line items, or ad units in your Google Ad Manager network over a given time period, based on a sample of cookies or mobile device IDs, such as Apple IDFAs or Android AdIDs. The reach report does not include impressions from Ad Exchange or AdSense.

Learn more about how reach is calculated.

Data availability
Reach report data is generated for all networks at the end of each day, according to the US/Pacific time zone, but it can take up to 3 days for data to be available in Ad Manager. 
  • Choose an end date for your Reach report that's at least 3 days in the past for best results.
  • Schedule monthly Reach reports on the fourth day of each month to ensure it contains a full data set.

Starting May 1, 2018, "Lifetime" Reach reports use the last 63 days of data to comply with EU General Data Protection Regulation (GDPR) requirements. The title of the dynamic date range is updated from "Lifetime" to "Last 63 days" to reflect this change. Weekly and monthly reports are not affected by this change.

Generate a Reach report

  1. Sign in to Google Ad Manager.
  2. Click Reports and then Queries.
  3. From the "Report type" list, select Reach.
  4. Decide on a date range.
    • Dynamic date ranges, such as "Last 63 days" or "Last month", are best for scheduled Reach reports.
    • Choose a fixed date range of full weeks or months to see weekly or monthly aggregated data.
  5. (Optional) Click Add new filter to narrow the results of your query. Learn more
  6. Select one or more dimensions and metrics:
    • Unique visitors
      The "reach," or number of unique visitors exposed to different advertisers, orders, line items, or ad units in your network.
    • Average revenue / visitor
      The revenue attributed to each unique visitor your network reached.
    • Average impressions / visitor
      The number of impressions attributed to each unique visitor your network reached.
  7. (Optional) Schedule and share your report.
  8. Click Run.

Breakdown reach data

  • Weekly
    View reporting data for each calendar week in the selected full (past) weeks. This option is available at the advertiser, ad unit, order, line item, or entire network level. A calendar week is the period spanning from Sunday to Saturday. If you select a different time period that spans multiple calendar week boundaries, the resulting report automatically shifts the start and end dates to match those of the closest calendar week.
  • Monthly
    View reporting data for each calendar month in the selected full (past) month. This option is available at the advertiser, ad unit, order, or line item level. This breakdown is the default setting for advertiser and ad unit reports.
  • Last 63 days (formerly, "Lifetime")
    View reporting data for the 63 days prior to the day the report runs. Instead of using aggregated weekly or monthly data, as in the example below, the "Last 63 days" date range uses a single continuous sample set to calculate reach.

How Google calculates reach

To calculate reach, a set of visitor cookies or device IDs reported as seeing the line item, advertiser, or other inventory is used as the sample. Only cookies or device IDs that exist at the time of the query are considered. If that set of visitors saw the line item or inventory an average of 5 times in the month, and there were 1,000,000 total impressions, the "Unique visitors" Reach metric is calculated by dividing total impressions (1,000,000) by the average view rate of the sample (5), for a total of 200,000 unique visitors.

For multiple months, Ad Manager uses an aggregation model. Below is an example of three months of data and how reach is calculate for each period:

Time period Total impressions recorded during this time period Total  impressions Sample size of cookies or device IDs Impressions generated by the sample group Calculated reach
January 1,000,000 1,000,000 100,000 500,000 200,000
February 1,000,000 2,000,000 100,000 100,000 333,333
March 1,000,000 3,000,000 100,000 0 500,000


Here's how the reach calculations work in this case:

  • January reach
    • Average impression count per member of the sample group
      Impressions generated by the sample group / Sample size of cookies or device IDs
      500,000 / 100,000 = 5
    • Total unique visitor count
      Total  impressions / Average impression count per member of the sample group
      1,000,000 / 5 = 200,000
  • January—February reach
    • Average impression count per member of the sample group
      Impressions generated by the sample group / Sample size of cookies or device IDs
      (500,000 + 100,000) / 100,000 = 6
    • Total unique visitor count
      Total  impressions / Average impression count per member of the sample group
      2,000,000 / 6 = 333,333
  • January—March reach
    • Average impression count per member of the sample group
      Impressions generated by the sample group / Sample size of cookies or device IDs
      (500,000 + 100,000 + 0) / 100,000 = 6
    • Total unique visitor count
      Total  impressions / Average impression count per member of the sample group
      3,000,000 / 6 = 500,000

Note that even if no new impressions are generated by the sample group, reach steadily increases. For extended campaigns, line items or queries, the actual rate of increase may slow down over time.

Why do I see "N/A" or "-" values in my report?
This means that there's not enough data to accurately calculate your reach for that row. There are two common reasons:
  • Reach data for any given period is only shown if the calculated error rate is less than 0.25

    If the error rate is greater than 0.25, reports display reach as "N/A' or '-'. Reach reports are based on sampling, therefore the error rate tends to be higher when the sample is smaller. Higher numbers of unique users and generally higher traffic leads to a reduction in the number of unavailable values.

  • Overlapping sample groups disrupt calculations

    For example, if you have 2 line items in an order with 100 unique visitors each, and your report includes both the Order and Line item dimensions, the sample group for the order will be shared by the line items, so the aggregated row for the order displays '-'. To see Order-level reach, run a report with only the Order dimension.

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