Country code
An ITU-assigned code begins the international numbering plan. Some codes are shared.
Read country codesCountryRangeLimits
The number is a clue, not a person
Read the code.
Know the limit.
Make sense of international numbers: country codes, original carrier ranges, assigned regions and the things a prefix cannot tell you.
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Plan & range only A prefix is read as plan, range and type — never a person or live location.
The example report shows how a responsible result labels evidence and unknowns — plan and range, never a person or live location.
Specimen / not a live lookupNO. 001
+44207946 0018
CALLING CODEAREA CODELOCAL PART
NUMBERING PLANUnited KingdomITU / +44
ASSIGNED AREALondonOfcom / 020
CURRENT CARRIERUnknownNot in this sample
PERSON OR LOCATIONNot inferableNot a prefix fact
Ofcom reserves 020 7946 0000–0999 for drama and will not allocate the range to providers. This is an explanation example, not a subscriber result.
The information ladder
Four layers.
Different confidence.
A useful number result separates directly assigned facts from weaker range-level clues and leaves unsupported claims blank.
Number range
National allocation data may point to a number type or geographic block.
Read range geographyOriginal carrier
Metadata can name an initial allocation, with portability limits.
Understand carrier dataUnknowns
A person, current carrier, active line and live location do not follow from the digits alone.
See the limits
Code explorer
Try the first layer.
This small offline demo recognizes a few example calling codes. It does not validate a full number, contact a carrier, store your input or identify a person.
Selected plans
One code can tell
different stories.
These routes explain the plan, then the limitations, instead of treating a code as a location pin.
The carrier problem
Original does not mean current.
When a number moves to a different provider, its prefix can still reflect the original allocation. Any current-carrier claim needs a separate up-to-date source.
Understand portabilityComplete reference
Choose the question
behind the number.
Every guide has an assigned task, official source and relevant next step.
Read a number
Carrier & type
Region & limits
Calling-code field notes
Field notes
Good data begins
with a limitation.
Short explanations of the mistakes that turn a prefix fact into a false conclusion.
Field note
Original carrier is not current carrier
Portability changes how an allocation record should be labeled.
Read note Field noteAn area code is not a map pin
Regional numbering is administrative geography, not live location.
Read note Field noteWhat “valid number” really means
A pattern can fit a plan without belonging to an active subscriber.
Read note