The calculated result is not stored because a calculated control can not be
bound to a table field, since the control source is the calculation formula.
To start with, if you are storing all the numbers that make up the
calculation formula, why store the calculated result?
You can calculate the value wherever you need it.
However, if there is a good reason for storing the result you could add a
hidden field bound to the table field, then use some event procedure to copy
the contents of the calculated control to the hidden one. One possibility
would be the lost focus event procedure for the last control that is
included in the expression.
Ragnar