The way you're doing it seems fine. Are you doing anything with the calculated value other than displaying it on the form? If not, you really don't need the custom property at all. You can just set the Value property of the textbox you're using to display the value. For example, in the InteractiveChange or LostFocus of the controls whose values you want to calculate you could say THIS.Parent.txtCalcValue.Value=...

>I've solved the problem with the custom property. Somehow the custom property was stored under Formset1 and I was looking under Formdoc1. I created a textbox with the ControlSource set to the custom property and the correct total was displayed. Is this the correct way of doing it? (The method was similar to a reply on a previous question.)
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>Petrus.