The rollup allows you to perform a calculation on an entire column or a Relation. The most basic computation for the rollup is Count.

For example, in the image below we create a rollup column that counts the number of items in the `Animals`

column.

## Column or relation source

You can perform a calculation on values in a column or a Relation Column. For example, in the app below we have a list of users with a relation.

## Calculations

The Rollup Column can perform different calculations based on the data it finds in the column or relation you select.

### Numbers

The rollup column can calculate the Count , Count Unique, Sum, Average, Range, Minimum and Maximum of number values in a column or relation.

### Dates

The Rollup Column can calculate the Count, Count Unique, Earliest and Latest of date values in a column or relation.

### Boolean

The Rollup Column can calculate the Count, Count Unique, Count True, Count False, All True, Some True

### Text

The Rollup Column can calculate Count or Count Unique

You can use the rollup in many ways. Our expense splitter template also uses the rollup column to calculate the Sum & Count of different columns.