Power BI Tooltips: Adding Context to Visuals

A good visual answers one question; a good tooltip answers the next one, without adding anything to the page until the reader asks. Power BI has three kinds of tooltip, and they can be combined on the same visual (Microsoft Learn: tooltips overview):

Visual tooltips: more than the defaults

By default, hovering shows the name and value of each field in the visual. Drag extra fields or measures into the Tooltip field well to add values without changing the visual, and choose an aggregation such as Sum, Average or Count for each (Microsoft Learn: visual tooltips). A revenue-by-country chart becomes more useful with order count, average order value and a rank in its tooltip.

Two options in the Format pane, under General then Tooltips, refine this:

• Tooltip fields only shows just the fields you added, dropping the visual's own fields.
• Sentence format only renders the tooltip as a sentence from a template, with field names in braces replaced by the hovered values.

A rank measure and a sentence template together read naturally:

Country Rank =
RANKX ( ALL ( Customer[Country] ), [Revenue] )

{Country} ranks {Country Rank} by revenue, with {Revenue} from {Orders} orders.

Add Country Rank and Orders to the Tooltip field well so the template can reference them; a name that is not available is shown exactly as typed. For charts with a drillable hierarchy, Microsoft suggests a measure using ISINSCOPE that returns the right label at each level, so the sentence reads correctly whether the chart shows categories or products.

Turn on the Actions footer and supported visuals also offer Drill down, Drill up and Drill through inside the tooltip, which saves readers hunting through right-click menus; drillthrough and drilldown covers setting up the targets.

Report page tooltips, step by step

When a few values are not enough, design a whole page to appear on hover (Microsoft Learn: report tooltips):

1. Add a new page and, in the Format pane's Canvas settings, set the page size to Tooltip.
2. Switch the page view to Actual size so you see the tooltip as readers will.
3. Name the page clearly, such as "TT Country detail".
4. Add a few visuals: for a country, perhaps a revenue card, a monthly trend line and its top five products.
5. In Page information, turn Tooltip on.
6. Drag the field it should serve, such as Country, into Tooltip fields.

Now any visual using Country shows this page on hover, filtered to the data point under the pointer. To choose a tooltip page for one visual, or when two fields each have a tooltip page and Power BI would pick only one, set it manually: in the visual's Tooltips card, pick the page from the Page dropdown; Auto reverts to the default.

Behaviours that surprise authors

• Line charts show one tooltip for all lines, and the legend field does not filter it. Hovering a date on a chart with three product classes shows the total for all three.
• Cross-highlighting changes the tooltip: it always shows the highlighted data, even when hovering over the faded part of a bar.
• Summarization must match. A tooltip page assigned to a field appears only on visuals where that field's summarization matches.
• Tables and matrices show the cell value on hover and have no Tooltip field well.

Limits to design around

• Tooltips are not interactive. Readers cannot click slicers or scroll inside them, so keep everything visible at once. If readers need to interact with the detail, use a drillthrough page instead.
• Screen readers cannot read report tooltip content, so never put the only copy of important information in a tooltip.
• Dashboards do not support report page tooltips, and a visual pinned to a dashboard shows the basic tooltip.
• Python and R visuals do not appear in report page tooltips.

Designing tooltips readers use

• Answer the obvious next question. On a country bar, readers want the trend and what sells there, not a repeat of the bar's value.
• Keep tooltip pages small, two or three visuals, and readable at a glance.
• Style them with the theme. Tooltips inherit theme colours, and the theme can set tooltip label, value and background colours; see themes and branding.
• Consider autoscale, the report setting "Tooltip size is affected by canvas size", so tooltips suit different screens.
• Use tooltips to take detail off crowded pages. Microsoft's optimization guide recommends report page tooltips over jamming extra visuals onto a page; performance tuning explains why fewer visuals load faster.

A page that uses tooltips well stays clean: the main visuals carry the story, and hover detail is there for readers who want it. Dashboard design covers the layout around them.

Charts, tables, KPI cards and drill-down and drill-through reports are part of the data visualization module of the Power BI course.

Sources

• Tooltips overview (Microsoft Learn) — Microsoft Learn
• Visual tooltips in Power BI (Microsoft Learn) — Microsoft Learn
• Create report tooltips in Power BI (Microsoft Learn) — Microsoft Learn
• Optimization guide for Power BI (Microsoft Learn) — Microsoft Learn