Here's an "assist" on Skip's routine...
This will leave the data on each sheet in a "normal" mode - i.e. NOT with all the cells of each sheet selected. I expect you'll prefer this un-selected option for the end-user.
Sub ConvertFormulas_ToValues()
Dim ws As Worksheet
Application.ScreenUpdating = False
For Each ws In Worksheets
ws.Select
With ws
.Cells.Copy
.Cells.PasteSpecial xlPasteValues
.Cells(1, 1).Select
End With
Next
Sheets(1).Select
[a1].Select
Application.CutCopyMode = False
Application.ScreenUpdating = False
End Sub
Regards, Dale Watson