In order to store the value calculated in your TextBox you will need to add some code to the Form's BeforeUpdate event. You already know that it is bad practice to store calculated values unless there is some historical reason, as you have, where the sales tax rate might change. In the BeforeUpdate event of the form put something like:
Me![TotalSalesField] = Me!txtTotalSaleCalcControl
Using your control and field names of course.
(RG for short) aka Allan Bunch Previous MS Access MVP acXP, ac07, ac10, ac13 - WinXP Pro, Win7 Pro, Win10 Pro
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