E.164 is the ITU standard for international phone numbers: a leading +, the country code (1-3 digits), and the subscriber number, with the total length capped at 15 digits. The validator accepts numbers in this canonical form.

Does it verify the number is reachable?

No. It is a syntactic check only. To verify reachability you need a carrier lookup or SMS confirmation — neither of which the local-only validator can perform.

Why does the US pattern differ from E.164?

US-formatted numbers commonly use (NNN) NNN-NNNN or NNN-NNN-NNNN. The US preset accepts those layouts; the E.164 preset enforces strict + prefix and digit-only formatting.

Is my phone input uploaded?

No. The regex runs locally in your browser.

phone regex · e.164 · us · batch

Validate any phone number with a regex

Switch between strict international E.164 and US formats. Single or batch. Runs locally.

Phone Number Validator

Mode

single

one value

Valid

Invalid

fail

Pattern

phone

E.164

input · single value

samples:

output · result

okValid

Pattern · E.164 /^\+[1-9]\d{1,14}$/

Quick Start

How to validate a phone number

Pick E.164 for international or US for the local format. Drop one number or a list.

01
Pick a format
E.164 = +<country><number>. US accepts (415) 555-1234 forms.
Patterns compile through the JavaScript RegExp constructor, so syntax errors surface immediately and engine quirks like Unicode property escapes (\p{L}) work when the u flag is on.
patternECMAScriptliterallive
input · literalformat · regex
E.164 | US
loaded · ECMAScriptPCRE · ready
02
Type or paste
Single mode for one number, batch for a list.
Each flag character mirrors the ECMAScript literal: g enables iteration, i folds case, m anchors per line, s lets . match newlines, u unlocks proper Unicode, y is sticky, and d emits indices.
flagsoptionsg · i · mlive
config · optionsvalue · flags
+14155551234
flags applied · liveECMA · live
03
Read the verdict
Pass/fail per line with the active pattern shown beside.
Watch for catastrophic backtracking on nested quantifiers — a common ReDoS source. The tool caps match counts to keep the page responsive on pathological patterns.
matchgroupshighlightReDoS-safe
run · outputresult · matches
ok +14155551234
matches · livegroups · live
04
Copy or export
Grab the output as JSON, CSV, or plain text — ready for your editor or pipeline.
Copy writes via navigator.clipboard.writeText; downloads use a Blob and object URL, so nothing transits the network and the output is byte-identical to what you see on screen.
copyexportclipboardblob
export · exportedready · saved
Copied
ready to shipsuccess

Pro tips

Regex patterns that don't melt down

Use named groups

(?<year>\d{4}) reads better than $1 and survives reordering. Supported in ECMAScript 2018+.

Anchor strictly

Use ^/$ with the m flag when matching whole lines. Without anchors, partial matches sneak through.

Avoid catastrophic backtracking

Nested quantifiers like (a+)+ can explode. Run patterns through ReDoS Detector first.

Escape every literal

Backslash any meta character you want literally: \.\$\^\*\+\?\[\]\{\}\|\\.

Test edge cases

Empty string, single character, unicode, the maximum length you expect — write fixtures for each.

Patterns aren’t parsers

Don’t parse HTML, JSON, or balanced parens with regex. Use a proper parser when the grammar is recursive.

Use Cases

When to validate phone numbers

Forms, list audits, and CRM data cleanup.

Sign-up forms

Catch typos before SMS bounce. Compiles through the JavaScript RegExp constructor — engine quirks (Unicode property escapes, sticky matching, named groups) work when their flags are on. Error messages cite the exact position of any syntax issue.

ReDoS-safe

CRM cleanup

Audit a list of imported numbers. Pairs with the ReDoS detector to catch catastrophic backtracking before you deploy. A pattern that handles 1k-character input fine can become a denial-of-service vector on attacker-controlled 1M-character input.

ECMA-compliant

Bulk SMS

Confirm a recipient list parses. Output exports as JavaScript, Python re, Java util.regex, .NET System.Text.RegularExpressions, PCRE, and POSIX — language quirks are highlighted on conversion so you don't ship a JS-only pattern to a Go service.

spec-grade

Customer support

Reject malformed input fast. Capture groups (named or numbered) round-trip cleanly into replacement strings, JSON output, or CSV extraction without re-typing. Backreferences ($1, ${name}) preserve semantics across languages.

cross-engine

API request bodies

Validate phone fields server-side. Test against edge cases — empty input, single character, max length, multibyte boundaries — to catch off-by-one and zero-length match bugs before they reach production.

test-ready

Migration

Surface bad data before import. All matching runs client-side so secret patterns never leave the browser. Useful when the pattern itself is sensitive (PII regexes, internal data formats, security filters).

production-ready

FAQ

Frequently asked questions

Is E.164 strict enough?

Syntax-strict, yes. For carrier-valid checks you need a service like libphonenumber or a lookup API.

Does it dial?

No — this is syntax only. A valid format doesn't guarantee the number is assigned.

Other country formats?

Build your own pattern with the Regex Builder, or reuse the E.164 pattern for international cases.

Are spaces allowed in E.164?

No — strict E.164 forbids spaces. Strip them before validating if your source is loose.

Is anything sent to a server?

No. The tool runs entirely in your browser — your pattern and sample text never leave the page.

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