Validate phone numbers in JavaScript and TypeScript

The plans in this file

Add the countries whose numbers you accept; the file and its tests below are generated again for them, in your browser.

• United Kingdom +44×
• United States +1×
• France +33×

1. The plans

PLANS holds one entry per plan: its region (the ISO code), the country code, the trunk prefix dialled before a national number, the exit code dialled before an international one, and a pattern per line type. The patterns are the plans' own, anchored, in the order the file tries them: the special ranges first (premium rate, toll-free, shared cost, VoIP, personal, pager, UAN, voicemail), then fixed line, then mobile. A plan that names no single exit code gets an empty one, and calls out of it use the + form.

// phone.mjs: validate, normalise and dial phone numbers with the national numbering plans.
// Plans: GB +44, US +1, FR +33 (data as of 2026-10-25).
// Other plans: https://phonelookup.dev/guides/validate-phone-numbers-javascript?plans=gb,us,fr
// Each pattern matches a national significant number: digits only, no country code, no trunk prefix.

/** @typedef {{ region: string, cc: string, trunk: string, exit: string, types: [string, RegExp][] }} Plan */
/** @typedef {{ e164: string, region: string, type: string, cc: string, nsn: string }} PhoneNumber */

/** @type {Plan[]} */
export const PLANS = [
  {
    region: 'GB', cc: '44', trunk: '0', exit: '00',
    types: [
      ['premiumRate', /^(?:(?:8(?:4[2-5]|7[0-3])|9(?:[01]\d|8[2-49]))\d{7}|845464\d)$/],
      ['tollFree', /^(?:80[08]\d{7}|800\d{6}|8001111)$/],
      ['voip', /^(?:56\d{8})$/],
      ['personalNumber', /^(?:70\d{8})$/],
      ['pager', /^(?:76(?:464|652)\d{5}|76(?:0[0-28]|2[356]|34|4[01347]|5[49]|6[0-369]|77|8[14]|9[139])\d{6})$/],
      ['uan', /^(?:(?:3[0347]|55)\d{8})$/],
      ['fixedLine', /^(?:(?:1(?:1(?:3(?:[0-58]\d\d|73[0-5])|4(?:(?:[0-5]\d|70)\d|69[7-9])|(?:(?:5[0-26-9]|[78][0-49])\d|6(?:[0-4]\d|5[01]))\d)|(?:2(?:(?:0[024-9]|2[3-9]|3[3-79]|4[1-689]|[58][02-9]|6[0-47-9]|7[013-9]|9\d)\d|1(?:[0-7]\d|8[0-3]))|(?:3(?:0\d|1[0-8]|[25][02-9]|3[02-579]|[468][0-46-9]|7[1-35-79]|9[2-578])|4(?:0[03-9]|[137]\d|[28][02-57-9]|4[02-69]|5[0-8]|[69][0-79])|5(?:0[1-35-9]|[16]\d|2[024-9]|3[015689]|4[02-9]|5[03-9]|7[0-35-9]|8[0-468]|9[0-57-9])|6(?:0[034689]|1\d|2[0-35689]|[38][013-9]|4[1-467]|5[0-69]|6[13-9]|7[0-8]|9[0-24578])|7(?:0[0246-9]|2\d|3[0236-8]|4[03-9]|5[0-46-9]|6[013-9]|7[0-35-9]|8[024-9]|9[02-9])|8(?:0[35-9]|2[1-57-9]|3[02-578]|4[0-578]|5[124-9]|6[2-69]|7\d|8[02-9]|9[02569])|9(?:0[02-589]|[18]\d|2[02-689]|3[1-57-9]|4[2-9]|5[0-579]|6[2-47-9]|7[0-24578]|9[2-57]))\d)\d)|2(?:0[013478]|3[0189]|4[017]|8[0-46-9]|9[0-2])\d{3})\d{4}|1(?:2(?:0(?:46[1-4]|87[2-9])|545[1-79]|76(?:2\d|3[1-8]|6[1-6])|9(?:7(?:2[0-4]|3[2-5])|8(?:2[2-8]|7[0-47-9]|8[3-5])))|3(?:6(?:38[2-5]|47[23])|8(?:47[04-9]|64[0157-9]))|4(?:044[1-7]|20(?:2[23]|8\d)|6(?:0(?:30|5[2-57]|6[1-8]|7[2-8])|140)|8(?:052|87[1-3]))|5(?:2(?:4(?:3[2-79]|6\d)|76\d)|6(?:26[06-9]|686))|6(?:06(?:4\d|7[4-79])|295[5-7]|35[34]\d|47(?:24|61)|59(?:5[08]|6[67]|74)|9(?:55[0-4]|77[23]))|7(?:26(?:6[13-9]|7[0-7])|(?:442|688)\d|50(?:2[0-3]|[3-68]2|76))|8(?:27[56]\d|37(?:5[2-5]|8[239])|843[2-58])|9(?:0(?:0(?:6[1-8]|85)|52\d)|3583|4(?:66[1-8]|9(?:2[01]|81))|63(?:23|3[1-4])|9561))\d{3})$/],
      ['mobile', /^(?:7(?:457[0-57-9]|700[01]|911[028])\d{5}|7(?:[1-3]\d\d|4(?:[0-46-9]\d|5[0-689])|5(?:0[0-8]|[13-9]\d|2[0-35-9])|7(?:0[1-9]|[1-7]\d|8[02-9]|9[0-689])|8(?:[014-9]\d|[23][0-8])|9(?:[024-9]\d|1[02-9]|3[0-689]))\d{6})$/],
    ],
  },
  {
    region: 'US', cc: '1', trunk: '1', exit: '011',
    types: [
      ['premiumRate', /^(?:900[2-9]\d{6})$/],
      ['tollFree', /^(?:8(?:00|33|44|55|66|77|88)[2-9]\d{6})$/],
      ['personalNumber', /^(?:52(?:3(?:[2-46-9][02-9]\d|5(?:[02-46-9]\d|5[0-46-9]))|4(?:[2-478][02-9]\d|5(?:[034]\d|2[024-9]|5[0-46-9])|6(?:0[1-9]|[2-9]\d)|9(?:[05-9]\d|2[0-5]|49)))\d{4}|52[34][2-9]1[02-9]\d{4}|5(?:00|2[125-9]|3[23]|44|66|77|88)[2-9]\d{6})$/],
      ['fixedLine', /^(?:983[2-57-9]\d{6}|(?:2(?:0[1-35-9]|1[02-9]|2[03-57-9]|3[1459]|4[08]|5[1-46]|6[0279]|7[02469]|8[13])|3(?:0[1-57-9]|1[02-9]|2[013-79]|3[0-24679]|4[167]|5[0-3]|6[01349]|8[056])|4(?:0[124-9]|1[02-579]|2[3-5]|3[0245]|4[023578]|58|6[349]|7[02589]|8[04])|5(?:0[1-57-9]|1[0235-8]|20|3[0149]|4[01]|5[179]|6[1-47]|7[0-5]|8[0256])|6(?:0[1-35-9]|1[024-9]|2[03689]|3[016]|4[0156]|5[01679]|6[0-279]|78|8[0-269])|7(?:0[1-46-8]|1[2-9]|2[04-8]|3[0-2478]|4[0378]|5[47]|6[02359]|7[0-59]|8[156])|8(?:0[1-68]|1[02-8]|2[0168]|3[0-2589]|4[03578]|5[046-9]|6[02-5]|7[028])|9(?:0[1346-9]|1[02-9]|2[0589]|3[0146-8]|4[01357-9]|5[12469]|7[0-3589]|8[04-69]))[2-9]\d{6})$/],
      ['mobile', /^(?:983[2-57-9]\d{6}|(?:2(?:0[1-35-9]|1[02-9]|2[03-57-9]|3[1459]|4[08]|5[1-46]|6[0279]|7[02469]|8[13])|3(?:0[1-57-9]|1[02-9]|2[013-79]|3[0-24679]|4[167]|5[0-3]|6[01349]|8[056])|4(?:0[124-9]|1[02-579]|2[3-5]|3[0245]|4[023578]|58|6[349]|7[02589]|8[04])|5(?:0[1-57-9]|1[0235-8]|20|3[0149]|4[01]|5[179]|6[1-47]|7[0-5]|8[0256])|6(?:0[1-35-9]|1[024-9]|2[03689]|3[016]|4[0156]|5[01679]|6[0-279]|78|8[0-269])|7(?:0[1-46-8]|1[2-9]|2[04-8]|3[0-2478]|4[0378]|5[47]|6[02359]|7[0-59]|8[156])|8(?:0[1-68]|1[02-8]|2[0168]|3[0-2589]|4[03578]|5[046-9]|6[02-5]|7[028])|9(?:0[1346-9]|1[02-9]|2[0589]|3[0146-8]|4[01357-9]|5[12469]|7[0-3589]|8[04-69]))[2-9]\d{6})$/],
    ],
  },
  {
    region: 'FR', cc: '33', trunk: '0', exit: '00',
    types: [
      ['premiumRate', /^(?:836(?:0[0-36-9]|[1-9]\d)\d{4}|8(?:1[2-9]|2[2-47-9]|3[0-57-9]|[569]\d|8[0-35-9])\d{6})$/],
      ['tollFree', /^(?:80[0-5]\d{6})$/],
      ['sharedCost', /^(?:8(?:1[01]|2[0156]|4[024]|84)\d{6})$/],
      ['voip', /^(?:9\d{8})$/],
      ['uan', /^(?:80[6-9]\d{6})$/],
      ['fixedLine', /^(?:(?:26[013-9]|59[1-35-9])\d{6}|(?:[13]\d|2[0-57-9]|4[1-9]|5[0-8])\d{7})$/],
      ['mobile', /^(?:(?:6(?:[0-24-8]\d|3[0-8]|9[589])|7[3-9]\d)\d{6})$/],
    ],
  },
]

2. Reading a number

parse keeps the digits and a leading plus. With the plus, or with the default region's exit code in front (00 from the United Kingdom, 011 from the United States), the first one to three digits are the country code: under ITU-T E.164 no code is the prefix of another, so at most one length names a plan, and the plans sharing a code (+1, +7, +44) are tried in turn. Without either, the number is national and is read in the default region's plan. The trunk prefix is tried stripped first, so “+44 (0)7400 123456” reads too. A number in both the fixed-line and the mobile ranges comes back as fixedLineOrMobile, which is every ordinary number in the +1 plans. Digits typed in other scripts are dropped with the punctuation; convert them first if your users type them. Anything no plan accepts gives null.

const byRegion = new Map(PLANS.map((p) => [p.region, p]))

/**
 * Reads a number the way people type it: "+44 7400 123456", "07400 123456", "00 44 7400 123456".
 * A number without + or an exit code is read in the plan of defaultRegion (an ISO code such as "GB").
 * @param {string} text
 * @param {string} [defaultRegion]
 * @returns {PhoneNumber | null} null when no plan in PLANS accepts it
 */
export function parse(text, defaultRegion) {
  const s = String(text).replace(/[^0-9+]/g, '')
  const digits = s.replace(/\+/g, '')
  if (digits.length < 3 || digits.length > 17) return null
  if (s.startsWith('+')) return international(digits)
  const home = byRegion.get(defaultRegion)
  if (!home) return null
  if (home.exit && digits.startsWith(home.exit)) return international(digits.slice(home.exit.length))
  return match([home, ...PLANS.filter((p) => p.cc === home.cc && p !== home)], digits)
}

// Country codes are prefix-free (ITU-T E.164): the first one to three digits that name a plan are the code.
function international(digits) {
  for (let size = 1; size <= Math.min(3, digits.length); size++) {
    const plans = PLANS.filter((p) => p.cc === digits.slice(0, size))
    if (plans.length) return match(plans, digits.slice(size))
  }
  return null
}

// The trunk prefix is tried stripped first: "+44 (0)7400 123456" is common.
function match(plans, nsn) {
  for (const plan of plans) {
    const tries = plan.trunk && nsn.startsWith(plan.trunk) ? [nsn.slice(plan.trunk.length), nsn] : [nsn]
    for (const national of tries) {
      const type = typeOf(plan, national)
      if (type) return { e164: `+${plan.cc}${national}`, region: plan.region, type, cc: plan.cc, nsn: national }
    }
  }
  return null
}

// The first matching type wins; a number in both the fixed-line and the mobile ranges is reported as such.
function typeOf(plan, nsn) {
  const hits = plan.types.filter(([, re]) => re.test(nsn)).map(([type]) => type)
  if (hits.length === 0) return null
  return hits[0] === 'fixedLine' && hits.includes('mobile') ? 'fixedLineOrMobile' : hits[0]
}

3. Writing and dialling it

Store the E.164 form, a plus and digits only: one string per number, and every other format follows from it.toTel writes the tel: URI for links (RFC 3966). dialFrom gives the digits a person dials from another country: the caller's exit code, the country code and the national number, or, between plans that share a country code, a national call with the trunk prefix. The dialling helper explains each case.

/** The tel: URI (RFC 3966), for links. @param {PhoneNumber} n */
export const toTel = (n) => `tel:${n.e164}`

/**
 * What to dial from a phone in fromRegion. Inside one country code (the UK and Jersey, the US and Canada)
 * the call is dialled like a national one, with the trunk prefix; otherwise the exit code, the country code
 * and the national number. The + form when fromRegion is not in PLANS or its plan names no exit code.
 * @param {PhoneNumber} n
 * @param {string} fromRegion
 */
export function dialFrom(n, fromRegion) {
  const from = byRegion.get(fromRegion)
  if (!from) return n.e164
  if (from.cc === n.cc) return from.trunk + n.nsn
  return from.exit ? from.exit + n.cc + n.nsn : n.e164
}

The tests

The cases are the plans' own example numbers, one per line type in international form; the first plan's mobile number again in national form, with “(0)”, and dialled with an exit code; then numbers no plan accepts, and three calls dialled. Their expected values are computed when the page is built, by the same logic in TypeScript. The generator behind this page is checked by running its output in node:test, for these plans and for all 245 plans at once.

node --test

import { test } from 'node:test'
import assert from 'node:assert/strict'
import { parse, toTel, dialFrom } from './phone.mjs'

test('reads each line type of each plan', () => {
  const cases = [
    // typed, default region, E.164, line type
    ['+44 7400 123456', undefined, '+447400123456', 'mobile'],
    ['+44 121 234 5678', undefined, '+441212345678', 'fixedLine'],
    ['+44 800 123 4567', undefined, '+448001234567', 'tollFree'],
    ['+44 56 1234 5678', undefined, '+445612345678', 'voip'],
    ['+44 901 234 5678', undefined, '+449012345678', 'premiumRate'],
    ['+44 70 1234 5678', undefined, '+447012345678', 'personalNumber'],
    ['+44 76 4012 3456', undefined, '+447640123456', 'pager'],
    ['+44 55 1234 5678', undefined, '+445512345678', 'uan'],
    ['+1 201-555-0123', undefined, '+12015550123', 'fixedLineOrMobile'],
    ['+1 800-234-5678', undefined, '+18002345678', 'tollFree'],
    ['+1 900-234-5678', undefined, '+19002345678', 'premiumRate'],
    ['+1 500-234-5678', undefined, '+15002345678', 'personalNumber'],
    ['+33 6 12 34 56 78', undefined, '+33612345678', 'mobile'],
    ['+33 1 23 45 67 89', undefined, '+33123456789', 'fixedLine'],
    ['+33 801 23 45 67', undefined, '+33801234567', 'tollFree'],
    ['+33 9 12 34 56 78', undefined, '+33912345678', 'voip'],
    ['+33 884 01 23 45', undefined, '+33884012345', 'sharedCost'],
    ['+33 891 12 34 56', undefined, '+33891123456', 'premiumRate'],
    ['+33 806 12 34 56', undefined, '+33806123456', 'uan'],
    ['07400 123456', 'GB', '+447400123456', 'mobile'],
    ['+44 (0)7400 123456', undefined, '+447400123456', 'mobile'],
    ['00 1 201-555-0123', 'GB', '+12015550123', 'fixedLineOrMobile'],
  ]
  for (const [text, region, e164, type] of cases) {
    const n = parse(text, region)
    assert.ok(n, text)
    assert.equal(n.e164, e164, text)
    assert.equal(n.type, type, text)
  }
})

test('rejects what no plan accepts', () => {
  assert.equal(parse('12', 'GB'), null)
  assert.equal(parse('+44 7400 12345'), null)
  assert.equal(parse('+49 1512 3456789'), null)
  assert.equal(parse('07400 123456'), null)
})

test('writes and dials', () => {
  assert.equal(toTel(parse('+44 7400 123456')), 'tel:+447400123456')
  assert.equal(dialFrom(parse('+1 201-555-0123'), 'GB'), '0012015550123')
  assert.equal(dialFrom(parse('+44 7400 123456'), 'US'), '011447400123456')
  assert.equal(dialFrom(parse('+44 7400 123456'), 'GB'), '07400123456')
})

What is specific to JavaScript

• Never put the g or y flag on a pattern you call test with: the regular expression then remembers lastIndex, and the same number answers valid, then invalid, then valid.
• \d means [0-9] in JavaScript, with or without the u flag, so the plans' patterns mean what they say.
• The patterns compile once, when the module is first imported. The same file runs in Node and in the browser; a bundler keeps one copy.
• TypeScript: the JSDoc types check as they are under // @ts-check or checkJs. In a .ts file, turn the two typedefs into type declarations and annotate parse and dialFrom the same way.