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Free tool

Free US phone number format checker.

Paste a US phone number to check it's correctly formed and see it in the international format your CRM and API calls expect. Runs in your browser; nothing is sent anywhere.

FreeRuns in your browserUS phone numbers only

Checked in your browser as you type. Nothing is sent anywhere.

ResultWaiting for a number
About this tool

What it checks.

A correctly formed number is the first thing to check, and the cheapest. If a number fails here, no dialer will reach it.

This tool checks the structure of a US number against the North American Numbering Plan and returns it in E.164, the +1 format most CRMs and APIs store.

  1. 1

    Paste a number

    Any common US format works: (212) 555-0162, 212.555.0162 or +1 212 555 0162.

  2. 2

    It's parsed in your browser

    The number is checked against US numbering rules. Nothing is sent to a server.

  3. 3

    See the result

    Whether it's correctly formed, and the number in E.164.

Limitations

What it can't tell you.

  • It doesn't check whether the number is in service.
  • It doesn't tell you whether the line is a mobile or a landline.
  • It can't tell you whether the number belongs to the person you're calling.
  • It can't tell you whether anyone will pick up.

For everything a format check can't tell you

Will This Person Answer checks validity, line type, activity, name match and litigation risk, and returns one answer: High chance, Low chance or Bad data.

Check 250 contacts free
Upload

Drop in a CSV, get answers.

The upload step in Will This Person Answer: drop a CSV with first_name, last_name and phone columns, up to 10,000 contacts, US phone numbers only
The upload step. A CSV with first name, last name and phone is all it needs; the app finds the columns for you.
FAQ

Questions, answered.

Is this tool free?

Yes, and it runs in your browser, so there's nothing to sign up for and nothing is stored.

Does a correctly formed number mean it works?

No. It means the number could exist. Whether it's in service, and whether it reaches the right person, needs a live check.

What is E.164?

The international phone number format: a plus sign, the country code and the number, with no spaces. For the US that's +1 followed by ten digits.

Keep reading

Related pages.

Phone validationA phone number validator that tells you who to call.Check that a US phone number is valid, what kind of line it is, whether it's active and whether it belongs to the person you're calling. Then get one answer: High chance, Low chance or Bad data.GuidesHow to validate phone numbers.Three levels of phone validation, from checking the format to checking the line to deciding whether a number is worth a call, with code for each.GlossaryWhat is phone intent?Phone intent is a prediction of how likely someone is to answer a call on a particular number. It's used to sort calling lists so reps dial the most reachable contacts.AnswerabilityWhat is an answerability score?An answerability score predicts how likely a person is to pick up when you call their number. Here's what goes into one, what comes out, and how it differs from checking that a number is valid.DevelopersA phone validation API that returns a decision.One POST with up to 100 contacts. Each comes back with a grade, a plain-language outcome and the action to take, so your code routes the contact instead of interpreting raw line data.

Know who’ll answer
before you call.

Grade 250 contacts free. No card required, and US phone numbers only.

  • US phone numbers only
  • No card required
  • One credit per checked contact
Check 250 contacts freeOr read the docs