Say I have 5000 cells in a row that i need to add a symbol into, in
this case ~. I have come up with a macro that will let me do it for
one cell at a time, but i need to do it for all of them at once.

Here is what i have so far:

Sub Tester8()
ActiveCell.FormulaR1C1 = Chr(126)
With ActiveCell.Characters(Start:=1, Length:=1).Font
.Name = "Symbol"
.FontStyle = "Regular"
.Size = 9
End With
End Sub

say i have c52 selected, when i run the macro it inserts the ~ as
expected but it also removes all text that was previously in the box.

Any ideas how i go about adding the symbol to all rows at once while
still preserving the text?