Write a formula in an Excel Cell using VBA

Treb, Matthieu's problem was caused by using Excel in a non-English language. In many language versions ";" is the correct separator. Even functions are translated (SUM can be SOMMA, SUMME or whatever depending on what language you work in). Excel will generally understand these differences and if a French-created workbook is opened by a Brazilian they will normally not have any problem. But VBA speaks only US English so for those of us working in one (or more) foreign langauges, this can be a headache. You and CharlesB both gave answers that would have been OK for a US user but Mikko understod the REAL problem and gave the correct answer (which was also the correct one for me too - I'm a Brit working in Italy for a German-speaking company).

The correct character (comma or colon) depends on the purpose.

Comma (,) will sum only the two cells in question.

Colon (:) will sum all the cells within the range with corners defined by those two cells.

You can try using FormulaLocal property instead of Formula. Then the semicolon should work.

The correct character to use in this case is a full colon (:), not a semicolon (;).