# Date range usage

Users can set a date range to be used at the chart, page, or report level. By default, Data Studio sets it to the most recent 28-day period excluding today.

This date range is used differently, depending on the [Ahrefs report type](./categorization-of-fields.md):

- *Historical.* The report type uses the date range to constrain historical data by a start and end date.
- *Start date only.* The report type uses the start date value, but ignores the end date value (and always returns data up to today).
- *Comparison*. The report type returns metrics for the provided end date, as well as comparison metrics for the provided start date.
- *Crawl selection.* The report type is used to select a Site Audit crawl. A date range selects the **completed crawl with the most recent start time in the specified date range**. For more information, see [Date range usage in Site Audit reports](./date-range-usage-site-audit.md).

Some fields in [each tool's field reference](./categorization-of-fields.md) have a "Used with date range" indicator. The meaning of this depends on how the field's report type uses the date range.

- If the usage is *Historical*, then the field is used as the date field to constrain by start/end date.
- If the usage is *Start date only*, then the field’s value is affected by the date range.
- If the usage is *Comparison*, then the field is a comparison metric.

The date range usage of each [Ahrefs report type](./ahrefs-report-types.md) is as follows.

|Tool            |Ahrefs report type       |Date range usage                        |
|----------------|-------------------------|----------------------------------------|
|Site Audit      |Project history          |Historical                              |
|Site Audit      |All issues               |Crawl selection                         |
|Site Audit      |Link explorer            |Crawl selection                         |
|Site Audit      |Page explorer            |Crawl selection                         |
|Site Explorer   |Top pages                |Comparison                              |
|Site Explorer   |Organic keywords         |Comparison                              |
|Site Explorer   |History charts           |Historical                              |
|Site Explorer   |Backlink stats           |Start date only                         |
|Site Explorer   |Backlinks                |Start date only                         |
|Site Explorer   |Traffic stats            |Comparison                              |
|Rank Tracker    |Overview stats           |Comparison                              |
|Rank Tracker    |Overview tags            |Comparison                              |
|Rank Tracker    |Competitors history      |Historical                              |
|Rank Tracker    |Competitors stats        |Comparison                              |
|Rank Tracker    |Competitors tags         |Comparison                              |
|Rank Tracker    |Competitors traffic share|Comparison                              |
|Rank Tracker    |Volume per country       |None                                    |
|Rank Tracker    |Volume history           |Historical                              |
|Brand Radar     |Overview history         |Historical                              |