How many digits is a Mexican phone number?

Since 2019 all Mexican numbers are a uniform 10 digits in national format: a 2 or 3-digit LADA (area code) followed by the local number. No more 8-digit + 2-digit-LADA split for big cities versus 7-digit + 3-digit elsewhere.

LADA is the Mexican area code. The three metro areas use 2-digit LADAs — 55 (Mexico City), 81 (Monterrey), 33 (Guadalajara) — followed by an 8-digit local number. Everywhere else uses a 3-digit LADA plus a 7-digit local number.

Why do some numbers start with +521?

The legacy mobile prefix +521 (the extra 1 after +52) was used to reach mobiles. As of 2020 it is no longer required — +52 plus the 10-digit number works for both fixed and mobile. The tool accepts +521 and strips the extra 1.

Does this detect mobile versus landline?

No. Since the 2020 dialling reform Mexico no longer distinguishes mobile and fixed numbers by prefix, so the LADA alone cannot tell them apart. This tool validates the 10-digit format and identifies the LADA region only.

Is my number sent anywhere?

No. All validation runs in your browser with JavaScript. The number is never uploaded, logged or transmitted — it stays entirely on your device.

Mexico Phone Number Validator

A Mexican phone number is, since the 2019 numbering reform, a uniform 10-digit national number: a LADA (area code) plus a local number. This free validator confirms the 10-digit format, recognises the three 2-digit metro LADAs, and handles the legacy +521 mobile prefix — so you can normalise contact data for WhatsApp Business, CRMs and SMS without rejected sends.

How it works

The validator normalises and checks each number:

Strip non-digits, then remove a +52 country code. If an extra 1 follows (+521, the old mobile dialling form), strip that too.
Require exactly 10 digits in the resulting national number.
Identify the LADA:
- 55 → Mexico City, 81 → Monterrey, 33 → Guadalajara (2-digit LADA + 8-digit local).
- any other valid 3-digit LADA (200–999, not starting 0 or 1) + 7-digit local.
Reject numbers whose first digit is 0 or 1, which are not valid LADA leads.

If the length is 10 and the LADA pattern matches, the number is valid and shown in clean E.164 form (+52XXXXXXXXXX).

Notes and example

Before 2020 you had to dial 044/045 or include the 1 in +521 to reach a mobile; that requirement was abolished, so a plain +52 + 10 digits now reaches any line. Because mobile and fixed numbers are no longer distinguishable by prefix, this tool reports the LADA region but deliberately does not guess mobile vs landline.

Example: input +52 1 55 1234 5678 normalises to 5512345678 — 10 digits, LADA 55 (Mexico City), so it is valid with E.164 +525512345678. Input 55 1234 567 fails because it is only 9 digits.

All processing is local — the number never leaves your browser.