Phone Number Regex Tester

Test and validate phone number patterns with regex — support international formats

What Is Phone Number Regex Validation?

Phone number regex validation uses regular expressions to check whether a string matches expected phone number formats. Phone numbers come in many patterns across countries and contexts: (555) 123-4567 (US formatted), +1-555-123-4567 (international with country code), 555.123.4567 (dot-separated), and +44 20 7946 0958 (UK format). A single regex can be written to accept multiple formats or tuned to match one specific format.

Phone validation is important for contact forms, CRM data entry, user registration, shipping forms, and any application that collects phone numbers. Poor validation either blocks valid numbers (frustrating users) or accepts garbage input (creating bad data). Testing regex patterns against real format examples lets you find the right balance. For full international validation, consider using a library like libphonenumber in addition to regex format checks.

How to Test Phone Number Regex Patterns

1. Select a pre-built phone number regex or write your own pattern
2. Paste sample phone numbers in various formats into the test string area
3. Matches highlight in real time — green for valid matches, red for non-matches
4. Adjust the pattern to accept or reject specific formats as needed
5. Test edge cases: international codes, extensions, formatting variations

Why Use PinusX for Phone Regex Testing?

PinusX processes your regex testing with 100% client-side execution in your browser. Your test phone numbers — which may be real customer data, internal contacts, or production samples — never leave your device. This protects personally identifiable information that should not be exposed to external servers. In November 2025, jsonformatter.org leaked over 80,000 user credentials that had been pasted for processing. PinusX prevents this by running all regex matching locally in your browser tab using JavaScript, with zero data transmission to any external system.

Frequently Asked Questions

What regex pattern works for US phone numbers?

A flexible US phone pattern is: ^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$ — this accepts (555) 123-4567, 555-123-4567, 555.123.4567, and 5551234567. Add ^\+?1?[-.\s]? at the start to optionally accept the +1 country code prefix.

Can one regex validate all international phone numbers?

A single regex can broadly match international formats with: ^\+?[1-9]\d{1,14}$ (E.164 format) which accepts 1-15 digits with an optional + prefix. However, validating that the number is actually correct for its country requires country-specific rules. Libraries like Google's libphonenumber handle this better than regex.

Should I strip formatting before validation?

It depends on your use case. If you store phone numbers in a normalized format (like E.164: +15551234567), strip all formatting first and validate the digit count. If you want to accept human-friendly formats, write a regex that allows parentheses, dashes, dots, and spaces around the digit groups.

How do I handle phone extensions?

Add an optional extension suffix to your regex: (\s*(ext|x|ext.)\s*\d{1,5})?$ — this matches common extension formats like ext. 123, x456, or ext 789 at the end of the phone number. Extensions are typically 1-5 digits.

What is E.164 phone format?

E.164 is the international standard for phone numbers: a + sign followed by 1-15 digits, no formatting characters. Example: +15551234567. It is the format used by most APIs (Twilio, AWS SNS), databases, and international dialing. The regex is simply: ^\+[1-9]\d{1,14}$

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