what is calculation field
In Tableau, a calculated field is a custom data field created to perform calculations on existing data within your dataset. Calculated fields allow users to generate new insights, metrics, or dimensions by applying mathematical operations, logical conditions, or string manipulations. They extend the analytical capabilities of Tableau beyond the original dataset.
To create a calculated field in Tableau:
Open Tableau and connect to your data source.
In a worksheet, right-click within the Data pane, then select "Create Calculated Field."
In the Calculation Editor, enter your formula using functions, operators, and references to existing fields.
Validate and save the calculated field with a name.
Drag and drop it onto your worksheet to use it in visualizations.