When Power BI Desktop creates visuals, it aggregates your data into chunks (or groups) based on values found in the underlying data. Often that's fine, but there may be times when you want to refine how those chunks are presented. For example, you might want to place three categories of products in one larger category (one group). Or you might want to see sales figures put into bin-sizes of 1,000,000 dollars, instead of evenly-divided 923,983 dollars.
In Power BI Desktop, you can group data points to help you more clearly view, analyze, and explore data and trends in your visuals. You can also define the bin size, often called binning, to put values into equally sized groups that better enable you to visualized data in ways that are meaningful.
To use grouping, select two or more elements on a visual by using CTRL+CLICK to multi-select elements. Then right-click one of the multi-select elements, and select Group from the menu that appears.
Once created, the group is added to the Legend bucket for the visual, and also appears in the Fields list.
Once you have a group, you can easily edit the members of that group by right-clicking the field from the Legend bucket or from the Fields list, and selecting Edit Groups.
In the Groups window that appears you can create new groups, or modify existing groups. You can also rename any group by double-clicking on the Group title in the Groups and members box, and typing a new name.
There are all sorts of things you can do with groups in this window. You can add items from the Ungrouped values list into a new group, or into one of the existing groups. To create a new group, select two or more items (using CTRL+click) from the Ungrouped values box and then click the Group button below that box.
You can add an ungrouped value into an existing group: just select the Ungrouped value, then select the existing group to which you want to add it, and click the Group button. To remove an item from a group, select it from the Groups and members box and then click Ungroup. You can also select whether ungrouped categories should be placed into the Other group, or should remain ungrouped.
Note: You can create groups for any field in the Fields well, without having to multi-select from an existing visual. Just right-click the field, and select Group from the menu that appears.
You can set the bin size for numerical and time fields in Power BI Desktop. You can use binning to right-size the data that Power BI Desktop displays.
To apply a bin size, right-click a Field and select Groups.
From the Groups window, set the Bin size to the size you want.
When you select OK, you'll notice that a new field appears in the Fields pane with (bins) appended. You can then drag that field onto the canvas to use the bin size in a visual.
To see binning in action, take a look at this video.
And that's all there is to using grouping and binning to ensure the visuals in your reports show your data just the way you want them to.