Access 2010 allows you to create a calculated field in a Table, rather than having to run a query or a report to carry out calculations. Where the calculated field refers to the values held in fields, those fields must be from the same table. The expression for the calculation is created in the Expression Builder.
• To create a calculated field in a table, switch to the Table Design View;
• On the Create Tab, select the Table Design button in the Tables group;
• Create the other fields, particularly those that will provide the data for your calculation;
• For your calculated field, enter the required Field Name and select Calculated as the Data Type;
The expression Builder will open to allow you to enter the Expression, selecting the appropriate Field Name, Operator, Function, and/or Constant .
Example expression: [Rate]*[Hours]
On each record, this field will multiply the value in the [Rate] field by the value in the [Hours] field.
Note that field names are enclosed in square brackets.