All tools on RegexCalc
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RegexCalc (main tool)
Free, instant client-side regular expression tester and calculator. Match highlighting, group capture extraction, and common pattern recipes.
Regex Replace Tester
Test regex replacements live with named group ($<name>), positional ($1..$9), and whole-match ($&) expansion, literal-$ escaping, and shareable URL links. Client-side.
Email Address Regex Pattern & Validator
Production-ready RFC 5322 email regex pattern tester, live matches, capture groups, and copyable code snippets.
Phone Number Regex Pattern (E.164 & US)
Validate US, international, and E.164 phone numbers with live interactive regex testing and group extraction.
IPv4 Address & CIDR Regex Pattern
Precise IPv4 address validation regex matching valid octets (0-255) and subnet CIDR masks with instant breakdown.
URL & Web Domain Regex Pattern
Robust URL validation regex with protocol (http/https), subdomain, port, query params, and anchor tag parsing.
UUID v4 Regex Pattern & Validator
Standard UUID (Universally Unique Identifier) version 4 pattern matching with hyphen support and hex validation.
Looking for explanations rather than a tool? RegexCalc guides cover 7 worked examples and gotchas.
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