Regex Editor & Tester

Matches lines consisting of 3 to 5 digits, optionally followed by a hyphen or space and 4 additional digits (ZIP+4 format). Intended for validating US zip codes like 12345 or 12345-6789, with the gm flags enabling matching across multiple lines of input. Note that the 3-5 digit range is looser than strict US validation, which requires exactly 5 digits before the optional extension.