Apps like WhatsApp want numbers in international format: a plus sign, the country code, then the number without its leading zero or any old dialling prefix. The USA is +1, Mexico +52, Spain +34. When the app shows a country list, pick the country there and type only the national digits.
The international format: plus, country code, number without the leading zero
Worldwide numbering follows the ITU recommendation E.164. In practice an app needs three parts in this order:
- The plus sign It replaces whatever you dial at home to call abroad, such as 00 or 011. In apps you never type those.
- The country code One to three digits: 1 for the USA and Canada, 52 for Mexico, 351 for Portugal.
- The national number Area code and subscriber number, without the 0 many countries put in front at home.
Examples by country (table)
| Country code | What follows it | |
|---|---|---|
| USA | +1 | Ten digits: area code and number |
| Mexico | +52 | Ten digits, no 044 or 045 |
| Spain | +34 | The number as written at home |
| Argentina | +54 | 9, then area code and number without 15 |
| Colombia | +57 | The mobile number as written at home |
| Turkey | +90 | Ten digits starting with 5 for mobiles, no leading 0 |
| United Kingdom | +44 | The number without its leading 0 |
| Germany | +49 | The number without its leading 0 |
| Portugal | +351 | Nine digits |
X stands for any digit. Every country and its code: all countries.
Special cases: Mexico, Argentina and numbers with a leading zero
- Mexico: +52 and ten digits since 2019. WhatsApp's help still asks for a 1 after +52, while the US regulator says mobiles no longer need it. If one form fails, try the other.
- Argentina: WhatsApp wants a 9 between +54 and the area code, and the local 15 removed, which gives 13 digits after the plus.
- Leading zero: in countries that dial 0 before a number at home, that 0 disappears after the country code. WhatsApp warns that leftover zeros cause registration errors.
- Apps that ask differently: TikTok's help says to choose the country and then enter the number with its 0 but without the country code. Read the field, not just the habit.
Common mistakes and the errors they cause
| What happens | Fix | |
|---|---|---|
| Country picked in the list and typed again | Two country codes in a row: invalid number | Type only the national digits |
| Leading 0 kept after the code | Rejected, or the code goes nowhere | Remove the 0 |
| 00 or 011 typed in an app | The app reads them as part of the number | Use the plus or the country list |
| Old prefixes like 044, 045 or 15 | One digit too many | Remove them |
| Wrong country in the list | The code is sent to a different number | Check the flag before you tap send |
Discord's help puts it plainly: a number must be properly formatted and valid under its country's numbering plan, and it must belong to a mobile phone. Landline and VoIP numbers fail even when the format is right; why apps reject a number covers those cases.
Still stuck after fixing the format? The code may be the problem, not the number: verification code not received.
Common questions
What is the WhatsApp country code for the USA?
+1, followed by the ten-digit number with its three-digit area code.
What is the country code for Mexico in WhatsApp?
+52, then the ten digits. If WhatsApp says the number is invalid, try adding a 1 after +52, which WhatsApp's help still mentions.
Do I type 00 before the country code?
No. In apps the plus sign or the country list replaces 00 or 011.
Why does the app say my number is invalid?
Usually a doubled country code, a leading 0 that should have gone, or the wrong country in the list. Some apps also refuse landline and internet numbers.