Bucket fields
Bucket fields allow you to categorize values based on fields available in the report type. This means you do not have to create custom formula fields for categories or segmentation of values if they are only relevant in reports. For example, sales managers can bucket or group opportunities by size based on amount, support managers can age cases based on days opened, and sales reps can group accounts into strategic accounts.
Note
Fields available as Bucket fields are Number, Percent, Currency, Picklist, and text fields.