Phone Number Formatter & Validator
Paste phone numbers and instantly format them to E.164 international standard. Detects country codes and validates length — perfect for WhatsApp API integration.
What Is E.164 Format?
E.164 is the international telephone numbering standard used by WhatsApp, Twilio, and most messaging APIs. It consists of:
- + prefix (plus sign)
- Country code (1–3 digits)
- Local number (up to 12 digits)
- Maximum 15 digits total (per ITU-T E.164)
Examples: +15551234567 (US), +447911123456 (UK), +919876543210 (India)
Frequently Asked Questions
Why does WhatsApp require E.164 format?
WhatsApp uses E.164 as its standard phone number format to ensure global uniqueness. Every WhatsApp API requires numbers in this format for sending messages.
What if my number shows as invalid?
Make sure you're including the correct country code and the right number of local digits. Hover over the error icon for specific guidance.
Can I validate if a number is on WhatsApp?
This tool validates the E.164 format. To check if a number is actually registered on WhatsApp, use our check-exists API endpoint.
Can I process numbers in bulk?
Yes! Paste multiple numbers separated by newlines or commas. The tool processes all of them at once.
Validate Numbers Programmatically
Use the check-exists endpoint to verify if a phone number is registered on WhatsApp before sending.