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Phone Number Management5 min read

How to Format Phone Numbers for International Calling

Calling internationally means converting a local phone number into a format that routes through international networks. The process is the same everywhere, but the details change by country.

Here's exactly how to format any phone number for international calling.

The Universal Formula

Every international call follows this structure:

[Exit Code] + [Country Code] + [Phone Number without trunk prefix]

Exit code: The digits you dial to "leave" your country's phone network. Varies by country.

Country code: 1–3 digits identifying the destination country.

Phone number: The local number with the trunk prefix removed.

Example: Calling a UK Mobile from the US

UK mobile number (local format): 07911 123456

  1. Exit code (from US): 011
  2. Country code (UK): 44
  3. Number without trunk prefix (remove leading 0): 7911123456

You dial: 011 44 7911 123456

Example: Calling a US Number from the UK

US number: (555) 123-4567

  1. Exit code (from UK): 00
  2. Country code (US): 1
  3. Number (no trunk prefix to remove): 5551234567

You dial: 00 1 555 123 4567

The + Shortcut

On any mobile phone, you can use + instead of the exit code. The phone automatically replaces + with whatever exit code your country uses.

+44 7911 123456    ← works from any country
+1 555 123 4567    ← works from any country

This is always the best approach on mobile phones. It works regardless of which country you're calling from, and it's the format used by WhatsApp, SMS gateways, and phone contacts. For a deeper look at how this relates to E.164 and other standards, see phone number formats explained.

Exit Codes by Country

| Country | Exit Code | Alternative | | -------------- | ------------------- | ----------- | | US / Canada | 011 | + | | UK | 00 | + | | Most of Europe | 00 | + | | Australia | 0011 | + | | Japan | 010 | + | | Russia | 810 | + | | India | 00 | + | | Brazil | 00XX (carrier code) | + | | South Africa | 00 | + |

Pro tip: On a mobile phone, always use + and forget about exit codes entirely.

The Trunk Prefix Problem

Most countries use a prefix digit (usually 0) for domestic calls. This digit is NOT part of the phone number — it's a routing instruction that tells the local network "I'm dialing within this country."

The rule: Drop the trunk prefix when adding the country code.

| Country | Trunk Prefix | Local Number | International Format | | --------- | ------------ | -------------- | -------------------- | | UK | 0 | 07911 123456 | +44 7911 123456 | | Germany | 0 | 030 12345678 | +49 30 12345678 | | France | 0 | 06 12 34 56 78 | +33 6 12 34 56 78 | | Australia | 0 | 0412 345 678 | +61 412 345 678 | | India | 0 | 098765 43210 | +91 98765 43210 |

Exceptions

United States / Canada: No trunk prefix. The 10-digit number is the same in local and international format. Just add +1.

Italy: The leading 0 is part of the number and must be KEPT:

  • Local: 06 1234 5678
  • International: +39 06 1234 5678 (keep the 0)

Russia: Uses 8 as trunk prefix (not 0):

  • Local: 8 495 123 4567
  • International: +7 495 123 4567 (replace 8 with country code)

Step-by-Step: Format Any Number

  1. Identify the country the number belongs to
  2. Find the country code (see common codes below)
  3. Remove the trunk prefix (usually 0, check exceptions)
  4. Combine: + + country code + remaining number
  5. Remove all formatting (spaces, dashes, parentheses are optional on most phones)

Common Country Codes

| Country | Code | Country | Code | | ----------- | ---- | ------------ | ---- | | US / Canada | +1 | India | +91 | | UK | +44 | China | +86 | | Germany | +49 | Japan | +81 | | France | +33 | Australia | +61 | | Spain | +34 | Brazil | +55 | | Italy | +39 | Mexico | +52 | | Netherlands | +31 | South Africa | +27 | | Russia | +7 | UAE | +971 |

For a complete list of 200+ country codes, see our International Phone Number Format Guide.

Formatting for WhatsApp

WhatsApp uses the same international format, but with no + sign and no spaces in the wa.me link:

Phone: +44 7911 123456
wa.me: https://wa.me/447911123456

For more details, see our WhatsApp Click-to-Chat Links Guide.

Common Mistakes

1. Keeping the trunk prefix

+44 07911 123456  ← Wrong (0 should be removed)
+44 7911 123456   ← Correct

This is the #1 mistake. The call might still connect in some cases, but it often fails or reaches the wrong number.

2. Using the wrong country code

If someone gives you a number and you don't know the country, guessing the country code is risky. Similar number patterns exist in different countries. An international phone number converter can detect the country from the number pattern and apply the correct code automatically.

3. Double country code

+1 +44 7911 123456  ← Wrong (two country codes)
+44 7911 123456     ← Correct

4. Forgetting the area code

Some people give you just their subscriber number (the last 6-8 digits) without the area code. You need the full national number before converting to international format.

5. Wrong exit code

If you're dialing from a landline and use the wrong exit code for your country, the call won't connect. Solution: use + on a mobile phone.

Automatic Formatting

If you'd rather not figure out country codes and trunk prefixes manually, NumSwift does it automatically:

  1. Paste any text containing phone numbers
  2. NumSwift identifies each number and its country
  3. Each number is displayed in correct international format
  4. One-click buttons for calling, WhatsApp, or SMS

This is especially useful when you have numbers from different countries in different formats — NumSwift normalizes them all. You can also use the phone number formatter to convert any number to a clean, standardized output.

Related Guides

Bottom Line

The formula is always the same: exit code (or +) + country code + number without trunk prefix. Use + on mobile phones to avoid memorizing exit codes. Watch out for trunk prefix exceptions (Italy keeps the 0, Russia uses 8 instead of 0). When in doubt, NumSwift handles the conversion automatically.