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Phone Number Validator

Everyday

Check if a phone number is correctly formatted for India, US, UK, or UAE. Instant result in your browser — enter digits only, no country code needed.

Reviewed by the thecalcu.com team · Last updated July 28, 2026

What is a Phone?

A Phone Number Validator checks whether a phone number conforms to the expected format for a given country. Phone number formats vary significantly around the world, the length, the valid starting digits, and whether a trunk prefix (like the leading 0 in the UK) is included are all country-specific. Validating phone numbers at the point of data entry reduces bad data, failed SMS deliveries, and call failures caused by transposed digits or missing digits.

This tool supports four countries: India, US/Canada, United Kingdom, and UAE. Select the country from the dropdown, enter the phone number as local digits (without the international dialling code), and the result updates instantly. Spaces, dashes, and parentheses in the input are stripped automatically.

For India, the tool checks that the number is 10 digits and starts with 6, 7, 8, or 9, the digits assigned to mobile subscribers by TRAI. For the US, it applies the North American Numbering Plan (NANP) rules. For the UK, it checks the 10–11 digit format starting with 0. For the UAE, it checks the 9-digit mobile format starting with 5 (or 05 with the trunk prefix).

What this tool does not check: whether the number is assigned to a real subscriber, whether it is active, or whether it is a mobile or landline number. Format validation only.

All validation runs in your browser, no phone number is transmitted or stored.

Why Use a Phone Number Validator?

A phone number with a single wrong digit is unreachable. A number that fails format rules entirely (wrong length, wrong starting digit) will be rejected by SMS gateways and telephony APIs before a message is even attempted. Catching format errors at data entry is cheaper than debugging failed delivery attempts or cleaning up a database of invalid numbers after the fact.

Common scenarios:

  • A registration form collects a mobile number for OTP delivery, validate format before the SMS gateway call to avoid unnecessary API charges on invalid numbers
  • An HR team importing employee records with phone numbers from a spreadsheet, flag structurally invalid entries before the import
  • A customer relationship management (CRM) system being populated with contacts from multiple sources, validate phone number format as part of the data quality check
  • Confirming your own phone number before providing it on a form or document

Who Should Use This Validator?

Developers building forms that collect phone numbers, add format validation on blur or submit to catch transposed digits and wrong-length numbers before the data is stored or used.

Data analysts and operations teams cleaning contact databases or CRM records, quickly identify which phone number entries are structurally invalid before running a campaign or sending communications.

HR and payroll teams maintaining employee records that include mobile numbers used for payroll OTPs, emergency contacts, or leave management systems.

Individuals who want to confirm a phone number they have written down or copied is correctly formatted before sharing it.

What Insights Does the Phone Number Validator Give You?

When the number is valid, the tool shows the country name and dial code, the number of digits, and a note that format validity does not confirm the number is active.

When the number is invalid, the error message states the expected format for the selected country, for example, "10 digits, must start with 6, 7, 8, or 9" for India. This tells you exactly what to fix.

Scope: format and length only for the selected country. Country detection is manual, select the correct country from the dropdown. The tool does not auto-detect the country from the number.

How to use this Phone calculator

  1. Open the Phone Number Validator on this page.
  2. Select the Country from the dropdown, India, US, UK, or UAE.
  3. Enter the phone number in the Phone Number field, digits only, without the country dialling code. The tool strips spaces, dashes, and parentheses automatically.
  4. The result badge updates instantly. A green Valid badge confirms the number matches the expected format.
  5. If the badge shows Invalid, read the error message, it states the required format for the selected country.
  6. Correct the number (check digit count and starting digit) and the badge updates immediately.

Formula & Methodology

Each country uses a regex pattern matched against the stripped input (digits only):

| Country | Pattern | Explanation |
|---|---|---|
| India | /^[6-9]\d{9}$/ | 10 digits, first digit 6–9 |
| US | /^[2-9]\d{2}[2-9]\d{6}$/ | 10 digits, NANP rules |
| UK | /^0\d{9,10}$/ | 10–11 digits, starts with 0 |
| UAE | /^0?5\d{8}$/ | 9 digits starting with 5, or 10 with trunk 0 |

Valid India example: 9876543210, 10 digits, starts with 9. Valid.

Invalid India example: 1234567890, starts with 1, which is not assigned to mobile subscribers. Invalid.

Related Tools

You may also find these useful: Email Validator, PAN Number Validator.

Frequently Asked Questions

A Phone Number Validator checks whether a phone number follows the correct format for a selected country. Different countries have different rules for the length and structure of phone numbers, an Indian mobile number is 10 digits starting with 6–9, a US number is 10 digits with specific area code rules, and a UK number is 10–11 digits starting with 0. This tool validates the format for India, the US, UK, and UAE, and tells you whether the number conforms to the expected pattern.
Enter the phone number as digits only, without the country code or dialling prefix. For India, enter just the 10-digit mobile number, do not include +91 or 0 at the start. For the US, enter the 10-digit number without the country code +1. The tool strips spaces, dashes, and parentheses automatically, so you can enter the number in any format.
A valid Indian mobile number is exactly 10 digits and must start with 6, 7, 8, or 9. Numbers starting with 0–5 are not assigned to mobile subscribers. Numbers starting with 1, 2, 3, 4, or 5 are typically landline or service numbers. The format is: `[6-9]XXXXXXXXX` (one of 6/7/8/9 followed by nine more digits).
A US phone number follows the North American Numbering Plan (NANP). It is 10 digits: a 3-digit area code, a 3-digit central office code, and a 4-digit subscriber number. Both the area code and central office code must start with a digit from 2–9 (0 and 1 are reserved for routing). The format entered should be 10 digits without country code: `[2-9]XX[2-9]XXXXXX`.
No. This tool validates the format only, it confirms the number follows the expected length and digit rules for the selected country. Whether the number is assigned to a real subscriber, whether it is currently active, or whether it is a mobile vs. landline number requires a live lookup through a telecom database, which this tool does not perform.
No. Validation runs entirely in your browser. The phone number you enter is never sent to a server, never logged, and never stored. You can safely validate any number without privacy concerns.
The most common reasons are: the number includes the country code (e.g. +91 or 91 for India, enter only the 10-digit local number), a leading 0 is included for India where it should not be, or the first digit is not in the expected range for that country. Read the error detail, it states the expected format explicitly.
The tool currently supports four countries: India, US, UK, and UAE. International numbers outside these four can be entered, but they will be validated against whichever country is selected in the selector. For comprehensive international phone number validation across all countries, a library like libphonenumber (which implements the full E.164 standard) is more appropriate.
E.164 is the international standard for phone number formatting. A number in E.164 format includes the country code, the area code, and the subscriber number, with a `+` prefix, for example, `+919876543210` for an Indian mobile number. This tool accepts the local number without the country code prefix, enter `9876543210` for India, not `+919876543210`.
The UK validator accepts numbers starting with 0, which is the standard dialling prefix for UK national numbers. UK mobile numbers start with 07 (e.g. `07911123456`). UK landlines start with 01 or 02 (e.g. `02012345678`). The total length is 10–11 digits including the leading 0.
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