Phone number lookup: check format and country code
Type any phone number to see whether its format is valid. For US and Canada numbers the tool checks the area code and exchange rules and shows the (555) 123-4567 and +1 E.164 formats. For other countries it finds the calling code. It never names the owner: there is no reverse lookup.
- ✅ Free
- 🔒 No sign-up
- 📱 Works on mobile
- ⚡ Instant results
Estimate only. This tool checks numbering formats, not whether a line exists or who owns it. Numbering rules change over time.
🔒 Everything runs in your browser. Your data and files never leave your device.
📌 Key facts
- A US phone number has 10 digits: a 3-digit area code, a 3-digit exchange and a 4-digit line number.
- Area codes and exchanges cannot start with 0 or 1, so the first digit of each is 2 through 9.
- In E.164 format, a US number such as (415) 555-0132 is written +1 415 555 0132.
- Numbers from 555-0100 to 555-0199 are reserved for fictional use in movies and examples.
- You can report spam text messages by forwarding them to 7726 (SPAM).
How a US phone number is built
A North American number has 10 digits in three parts, written (NPA) NXX-XXXX.
| Part | Digits | Rule |
|---|---|---|
| Area code (NPA) | 3 | First digit 2 to 9, cannot end in 11 |
| Exchange (NXX) | 3 | First digit 2 to 9, cannot end in 11 |
| Line number | 4 | Any digits |
E.164: +1 + area code + exchange + line = +14155550132
The same plan covers the US, Canada and many Caribbean countries, all with country code +1. Toll-free area codes are 800, 833, 844, 855, 866, 877 and 888.
E.164 and country calling codes
E.164 is the international standard: a plus sign, the country code, then the national number, at most 15 digits in total, with no spaces. Forms, text-message services and apps ask for this format.
| Country | Code | Example |
|---|---|---|
| United States, Canada | +1 | +1 415 555 0132 |
| United Kingdom | +44 | +44 20 7946 0958 |
| Mexico | +52 | +52 55 1234 5678 |
| India | +91 | +91 98765 43210 |
To call abroad from the US, dial 011 then the country code and the number, or just press + on a mobile phone.
Stop robocalls and telemarketing calls
- National Do Not Call Registry: free, run by the FTC. Register a home or cell number once; it does not expire.
- Report unwanted calls to the FTC, or text spam to 7726.
- Block the number in your phone, and turn on your carrier's spam filter.
- Robocalls selling something without your written consent are illegal, whatever the registry says.
This page checks formats only. It does not look up who owns a number, and nothing you type is sent or stored.
Phone number lookup: what each part means
A US number follows the North American Numbering Plan. Each block tells you something.
| Part | Example | Meaning |
|---|---|---|
| Country code | +1 | United States and Canada |
| Area code | 415 | A region, such as San Francisco |
| Exchange | 555 | A central office block |
| Line number | 0132 | The individual line |
However, mobile numbers keep their original area code even when the owner moves. So an area code is a clue, not proof of where the caller is.
Phone number lookup: spotting scam calls
Scam calls often follow the same script. For example, a fake bank agent creates urgency to get a code.
- Never read a texted verification code to a caller.
- Hang up and call your bank at the number on your card.
- Do not call back a foreign number that rang once.
- Be careful with unfamiliar premium-rate numbers.
Also, caller ID can be spoofed, so a familiar number is no guarantee. Report abuse to your carrier and to the national Do Not Call Registry to help block repeat offenders.
Phone number lookup: related safety habits
A suspicious call can hide a phishing attempt. So combine the tool with good habits.
Before you act on a message about a payment, validate the account with the IBAN validator. Likewise, secure your accounts with a login from the password generator. If you work with international banks, the SWIFT code decoder explains bank identifiers too.
Finally, if you need a number for a giveaway, draw one with the random number generator instead of using real phone numbers.
What to do after a suspicious call
Stay calm when a call feels wrong. First, give no personal details. Next, hang up if the caller pushes. Then block the number in your phone settings. Finally, report it if it is abusive telemarketing.
If you already shared details, act fast. For example, call your bank to freeze the card. Also, change your passwords. Reacting within the hour limits a lot of damage.
3 real-life examples
A valid San Francisco number
You type (415) 555-0132. Area code 415 starts with 4 and exchange 555 starts with 5, so the format is valid. E.164 is +14155550132, and the area code points to San Francisco, California.
An invalid area code
The number 111-555-0132 fails: an area code cannot start with 1. The same applies to 911 or 411, which are service codes. Fix the typo and check again.
A UK number in E.164
You type +44 20 7946 0958. The +44 matches the United Kingdom, and the 10 digits after it make a plausible London number (020 7946 0958 when dialed inside the UK).