Regex Editor & Tester

Validates and captures a flexible numeric string: an optional +/- sign, digits with either a period or comma as the decimal separator (e.g. '3.14', '3,14', or '.5'), optional surrounding whitespace, and an optional trailing % sign. Capture groups extract the sign, integer digits, and fractional digits so you can rebuild a sanitized plain real number. The atomic group (?>...) prevents backtracking for deterministic matching. Ideal for normalizing localized percent input in .NET before conversion.