This free phone validator checks whether a phone number is valid.

A phone validator tells you whether a number is real before you call, text or save it.

A phone validator returns these fields, and each one answers a different question.

This is an invented result for a made-up number, laid out the way a check comes back. The first six fields are free on this page, and the 7-day free trial opens the rest.

You can validate a phone number in three steps.

A phone validator checks a number's format and then its carrier record before it answers.

This is the path one check takes. A number can be written correctly and still not be assigned to anyone, so the format check alone is not the answer.

You can validate a whole list of phone numbers with one CSV file.

The free tool checks one number at a time. With a 1Lookup account you upload a CSV file in the dashboard, pick the column that holds the numbers and download the same file back with the result columns filled in on every row.

• 1 credit a number, the same price as one API lookup.
• Up to 2 million rows in one CSV file.
• Up to 1,000 API requests a minute on every account.

The phone validation API returns the same answer as JSON from one request.

Send the number in international format (+1 and ten digits for the US) to the phone endpoint with your API key. Each request costs 1 credit, and every account can send up to 1,000 requests a minute. The validity answer is in classification.number_status: ACTIVE, INACTIVE or INVALID for US and Canadian numbers, and VALID or INVALID for numbers in other countries.

curl -X POST https://app.1lookup.io/api/v1/phone \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"phone_number": "+14155552671"}'

import requests

response = requests.post(
    "https://app.1lookup.io/api/v1/phone",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={"phone_number": "+14155552671"},
)
data = response.json()["data"]
print(data["classification"]["number_status"])

const response = await fetch('https://app.1lookup.io/api/v1/phone', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ phone_number: '+14155552671' })
})
const { data } = await response.json()
console.log(data.classification.number_status)

{
  "success": true,
  "data": {
    "request": { "type": "phone", "input": "+14155552671" },
    "classification": {
      "line_type": "MOBILE",
      "number_status": "ACTIVE"
    },
    "insights": {
      "reachability": { "is_reachable": true },
      "compliance": { "dnc_listed": false, "dno_flag": false }
    },
    "metadata": { "credits_used": 1, "credits_remaining": 9998 }
  }
}

To run the same check from your own software, see our phone validation API.

Who uses this tool

Every area code has its own page with the places it covers, the local time there, and what to do when a call from it looks spoofed. These are the codes people look up most.

• 213Los Angeles
• 646New York City
• 917New York City
• 202Washington
• 404Atlanta
• 702Las Vegas
• 786Miami
• 415San Francisco
• 206Seattle
• 954Fort Lauderdale
• 323Los Angeles
• 929New York City

Area code 213, downtown Los Angeles, also has a page for each of its 786 prefixes, with the company NANPA lists as the holder.

New area codes catch people out, because a number from one looks unfamiliar even when it is local. These are the newest working codes.

• 465New York, since Jun 2026
• 483Alabama, since Feb 2026
• 471Mississippi, since Jan 2026
• 679Michigan, since Nov 2025
• 457Louisiana, since Sep 2025
• 729Tennessee, since Sep 2025

A lookup often names a company you have never seen on a bill. Each page below says what the company is and where it holds numbers.

• Onvoy, LLCSupplies numbers to VoIP and app-based phone services
• Level 3 Communications, LLCLumen's business and wholesale network
• Bandwidth.com CLEC, LLCSupplies numbers to VoIP and app-based phone services
• Neutral TandemWholesale phone carrier
• New Cingular Wireless PCS, LLCMobile network
• T-Mobile USA, Inc.Mobile network
• Peerless NetworkWholesale phone carrier
• Teleport Communications America, LLCAT&T's business phone network

To see who holds America's phone numbers overall, read our study Who Hands Out America's Phone Numbers in 2026.

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