What NUMBERVALUE does
NUMBERVALUE converts an amount stored as text into a number you can calculate with. You can tell it which decimal and grouping characters the source uses, so an imported comma decimal doesn't have to match your Excel settings.
The separator arguments describe the input. Your cell's number format still controls how the result looks. If the source already follows your current settings, VALUE may be enough.
Practical examples
Convert an amount with comma decimals
Suppose the imported text is 1.234,56: the dot groups thousands and the comma marks the decimal part.
=NUMBERVALUE("1.234,56",",",".")The result is the number 1234.56. The second argument means decimal comma; the third means grouping dot. Swapping them would describe a different source convention.
Read an imported percentage
For the text 12,5%, use the same separator settings:
=NUMBERVALUE("12,5%",",",".")The result is 0.125. Percentage formatting displays it as 12.5% with US number settings. NUMBERVALUE has already applied the percent sign, so don't divide the result by 100 again.
Common mistakes and notes
Empty text becomes zero
=NUMBERVALUE("") returns 0. If A2 is a comma-decimal amount that may be blank, =IF(A2="","",NUMBERVALUE(A2,",",".")) keeps an empty input empty. Decide whether missing amounts and zeros mean different things before filling down.
Explicit separators still need a known source
Omitting either separator uses the current locale for that argument. Only the first character of a supplied separator is used. Don't guess whether 1,234 means 1234 or 1.234: check a known amount or the export settings first.
Spaces and misplaced separators behave differently
NUMBERVALUE ignores ordinary spaces, even inside a number, and ignores grouping separators before the decimal. A repeated decimal separator or a grouping separator after the decimal produces #VALUE!. Other Unicode whitespace may need separate cleanup. Each trailing percent sign applies another division by 100. These rules are documented in Microsoft's NUMBERVALUE reference.
Keep identifiers as text
Converting 00731 produces the number 731. Keep meaningful leading zeros in an ID field; use ISNUMBER to check amounts that should have converted successfully.