Definition
What is MSISDN? Meaning, format and example
MSISDN stands for Mobile Station International Subscriber Directory Number. It is a mobile phone number in full international (E.164) format: the country code first, then the national number, 15 digits at most. 3GPP's own specifications call it the Mobile Subscriber ISDN number.
API form44770090012312 digits
API form1202555014311 digits
Both numbers are in ranges kept for fiction (Ofcom's 07700 900xxx and North America's 555-0100 to 555-0199), so they belong to no one.
MSISDN at a glance
- Meaning
- Phone numberof a mobile subscription, in E.164 form
- Format
- CC + NDC + SNcountry code, national destination code, subscriber number
- Length
- 15 digits maxcountry code included (ITU-T E.164)
- Not the same as
- IMSI · ICCID · IMEIthe subscription, the SIM card and the handset
MSISDN format
Three parts, 15 digits at most. 3GPP TS 23.003 defines the structure; ITU-T E.164 sets the plan and the length.
- CC
Country code
1 to 3 digits. It names the country: 44 for the United Kingdom, 1 for the US and Canada, 91 for India.
- NDC
National destination code
Points to a network, a region or a service inside the country. In GSM and UMTS an NDC is allocated to each mobile network. In North America the area code takes its place.
- SN
Subscriber number
The rest. It identifies the line inside that range, and its first digits can carry extra routing information.
How to write an MSISDN
- Digits only, 15 at most, country code included.
- People write a + in front. APIs and HLR requests usually take the digits without it: 447700900123, not +44 7700 900123. Bitcall's HLR API examples use that form.
- Drop spaces, dashes and the leading 0 of the local form: the UK number 07700 900123 becomes 447700900123.
- How the national number splits into NDC and SN differs by country, so never split by a fixed length. Use the free checker or a phone number library.
Sources: 3GPP TS 23.003 V19.8.0 (2026-09), clauses 3.1 and 3.3; ITU-T E.164 (the 15-digit limit and the country code plan).
MSISDN vs IMSI vs ICCID vs IMEI
Four numbers, four different things. Only the MSISDN is a number you dial.
| Number | What it identifies | Where it lives | Length and format |
|---|---|---|---|
| MSISDN | The phone number of a mobile subscription: the number people dial. | In the operator's subscriber records, linked to the SIM. One subscription can have more than one, and a data-only one can have none. | CC + NDC + SN, 15 digits at most (E.164). |
| IMSI | The subscription itself, inside the network. | On the SIM and in the operator's subscriber database. Callers never see it. | MCC (3 digits) + MNC (2 or 3) + MSIN, 15 digits at most. |
| ICCID | The SIM card. | Stored on the SIM, and often printed on the card. | Starts with 89; 19 or 20 digits (ITU-T E.118). |
| IMEI | The handset. | In the phone, not on the SIM. | 15 digits: an 8-digit type allocation code, a 6-digit serial number and a check digit. |
Put the same SIM in another phone and the IMEI changes, while the IMSI, the ICCID and the number stay with the subscription. 3GPP lets an operator change the IMSI without changing the number, and the other way round.
Sources: 3GPP TS 23.003 V19.8.0 (2026-09), clauses 2.2 (IMSI), 3.2 and 3.3 (MSISDN) and 6.2.1 (IMEI); ITU-T E.118 and the ITU's issuer identification number page (ICCID); ITU-T E.164 (MSISDN).
How to find your MSISDN
It is your own mobile number. These are the places to look.
In your phone's settings
Look in the SIM or About section for an entry such as My Number or SIM status. The label differs by phone and software version.
From your operator
Its app, its account page or its customer service can tell you the number tied to your SIM. Operators also have a USSD code for it, but the code differs by operator and country, so ask yours rather than trust a list.
In the form an API expects
However you find it, write it in E.164: country code first, digits only. The free phone number checker turns a number you type into that form.
A data-only subscription can be set up without an MSISDN (3GPP TS 23.003, clause 3.1), so on some SIMs there is no number to find.
MSISDN in APIs and HLR lookups
In SMS, voice and number-verification APIs, msisdn is the name of the field that carries a mobile number.
An HLR lookup takes an MSISDN and asks the mobile network about it. The result says whether the number is live right now, which network it is on today with that network's MCC and MNC, whether it was ported and whether it is roaming. Bitcall's API calls the field number and takes it in the form above. Its results never include the IMSI.
- Validate the format first, free, with the free phone number checker.
- Look up the MCC and MNC that come back in the MCC MNC list.
- INVALID_MSISDN means the number is not a valid, assigned mobile number: check the format, then the number itself.
Request
curl -X POST https://api.bitcall.io/v1/hlr/lookups \
-H "x-key-id: $BITCALL_KEY_ID" \
-H "x-api-secret: $BITCALL_API_SECRET" \
-H "Content-Type: application/json" \
-d '{"lookupType":"hlr-single","productCode":"hlr:V11","number":"447700900123"}'Result (trimmed)
{
"data": {
"status": "completed",
"price": {
"amount": 0.0038,
"currency": "EUR"
},
"result": {
"connectivityStatus": "CONNECTED",
"reachable": true,
"mccmnc": "23415",
"mcc": "234",
"mnc": "15",
"currentNetwork": "Vodafone UK",
"originalNetwork": "O2 UK",
"originalCountryName": "United Kingdom",
"originalCountryCode": "GB",
"originalCountryPrefix": "44",
"ported": true,
"portedNetworkName": "Vodafone UK",
"roaming": false
}
}
}MSISDN FAQ
Straight answers about what an MSISDN is and how to use one.
MSISDN stands for Mobile Station International Subscriber Directory Number. It is the phone number of a mobile subscription, written in full international (E.164) format. 3GPP's specifications call it the Mobile Subscriber ISDN number.
447700900123 is an MSISDN: country code 44 for the United Kingdom, then the national number 7700 900123. Written for people it is +44 7700 900123. A US example is 12025550143, which is +1 202 555 0143. Both are in ranges kept for fiction, so they belong to no one.
The MSISDN is the phone number people dial. The IMSI identifies the subscription inside the network: it is stored on the SIM and made of the MCC, the MNC and a subscriber number. 3GPP lets an operator change one without changing the other. Callers never see the IMSI, and Bitcall's HLR lookups never show it.
For a mobile number, yes, with one condition: the MSISDN is the number in full international form. 07700 900123 is the local way to write a UK number, and 447700900123 is its MSISDN. A subscription can have more than one MSISDN, and a data-only one can have none.
Two checks answer two questions. To see whether the format is valid, and its country and E.164 form, paste it into the free phone number checker. To see whether the number is connected right now, which network it is on, and whether it is ported or roaming, run an HLR lookup, from €0.0038 per number, charged only when the lookup succeeds.
Country code, national destination code, subscriber number: CC + NDC + SN. It is digits only and 15 digits at most (ITU-T E.164). People write a + in front; APIs usually take the digits without it, for example 447700900123. To see how a network's own code works, browse the MCC MNC list.
In Bitcall's HLR results, INVALID_MSISDN means the number is not a valid, assigned mobile number. Check the format first: country code, digits only, no leading 0. If the format is right, the number may never have been assigned.
Check an MSISDN before you send to it
Create a free account, top up by card, PayPal or crypto, and run your first lookup in minutes. From €0.0038 per number, charged only for lookups that succeed.