Calculated columns by default appear on all out of the box display forms due to the fact that they are ‘optional’ when applied to the list / content type. There is no way to change it to hidden using the Web GUI.
You will need to use SharePoint Designer to be able to set the column to Hidden.
- Open the site in SharePoint Designer, ensure you have the appropriate level of permissions.
- Click on Lists and Libraries
- Select the List / Library you wish to modify.
- Under Content Types, select the Content Type that has the calculated column.
- Under Content Type, click Edit Content Type Columns.
- On the columns editor, click on the calculated column you wish to edit.
- On the Property column, click ONCE on the word ‘Optional’ and wait. It will take 1-2 seconds before you see a dropdown box.
- Select the Hidden option, click Push Changes to Sites and Lists and Save.
Your column should now be hidden.