@p45cal. Thank you for your answer. I understand the problem of using the same name for modules and UDFs, but, as the attached file, I am used to use “01” at the end of modules name to differentiate them from UDf names. Does this approach also confuse excel? By “you need to use sheet-qualified references “do you mean I should modify my code or the way the inputs are addressed in the UDF? Can you provide a link that describe your point? (I searched web by “sheet-qualified references for u VBA” but I got results that were mostly related to SUBs not UDFs)