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- Last reviewed:
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- Reviewed by countrycalling.codes editorial team
Dialing sequence, step by step
- 1
Start with + on a mobile, or 011 when the United States network requires an all-digit access prefix.
- 2
Add 44, the country calling code for United Kingdom.
- 3
Add the destination national significant number. Remove the national prefix 0 before adding +44. The 0 is not part of the national significant number in international format.
Use +44 from a mobile or saved contact. On a US line that requires an all-digit international access code, replace + with 011.
Mobile and landline examples
X means a subscriber digit placeholder, so these patterns explain the transformation without publishing a private callable number. Save the + format; use the access-prefix format only for a call that starts in United States.
| Number type | Domestic in United Kingdom | Save on mobile | Dial from United States |
|---|---|---|---|
| Mobile | 07700 900XXX | +44 7700 900XXX | 011 44 7700 900XXX |
| Landline | 020 7946 XXXX | +44 20 7946 XXXX | 011 44 20 7946 XXXX |
How the international format is built
Portable contact format
+ 44 + national significant number
The + represents international access. It is display notation, not one of the E.164 digits.
Digits-only call from United States
011 + 44 + national significant number
The first part routes out of the origin network and must not be stored as part of the destination.
E.164 limits the full international number to 15 digits and excludes international and national prefixes. See the E.164 and international-format guide for the reusable structure and regional exceptions.
Common mistakes for this route
- Keeping the UK domestic 0, which produces an incorrect 011 44 0… dial string.
- Saving 011 in the contact instead of the portable +44 destination format.
Country code references
Related country-pair guides
Standards and country numbering-plan sources
- ITU-T E.164: The international public telecommunication numbering planInternational Telecommunication Union. Verified 2026-07-19.
- ITU-T E.123: Notation for national and international telephone numbersInternational Telecommunication Union. Verified 2026-07-19.
- National numbering plan: United StatesInternational Telecommunication Union. Verified 2026-07-19.
- The National Telephone Numbering PlanOfcom. Verified 2026-07-19.
- National numbering plan: United KingdomInternational Telecommunication Union. Verified 2026-07-19.
See our editorial and sourcing methodology.