Social security number

Do you know if the social security number Is it correct? With our tool you can calculate the control digits of your affiliation number, i.e. by entering the first 10 digits of your social security number we will calculate the remaining digits.

If the check digits match those of the social security number you have, then it is valid. Otherwise, you will need to look on your health card for the correct number.

How many digits does the social security number have?

The social security affiliation number has 12 digits although if you have been contributing for many years, your number may only have 11 digits.

¿What the social security number looks like? For example, let's imagine that our social security number is 121234567821:

  • The first two digits refer to the code of the province that issued the affiliation number (NAF).
  • The next eight digits (seven if you have the old format) is a sequential number that the Social Security Administration generates automatically when someone registers for the first time.
  • The last two digits are the control digits and are used to verify that the written numerical sequence is correct. In the social security number we have used as an example we see that the check digits should be 05 so the number would be wrong.

Where to get my social security number

There are multiple sites where you can get your membership numberHere are some of the most important ones:

  • On the health card
  • On your payroll
  • In the prescriptions written by your family doctor
  • In the employment contract
  • At an ambulatory presenting your ID card
  • In the receipt of unemployment benefits or unemployment papers
  • At Social Security offices
  • In the employee's employment history report
  • At the social security telephone number: 901502050

Social security number on the health card

The following are some examples of how the social security number on the health card from different territories:

Social security number in Madrid health card
Pensioner health card

Requesting a duplicate social security number

If you want to request a duplicate health cardYou can go in person to your ambulatory. If you want a duplicate of the affiliation resolution, you will have to go to the Social Security General Treasury of your city.

To make online procedures in the social security system, you must access the official website.

Once inside, access the section dedicated to citizens and you will be able to request multiple reports and certificates telematically and among them, request a duplicate membership document.

¿Qué otros trámites puedes hacer? La verdad que el abanico es bastante amplio y puedes solicitar informes de la vida laboral, retenciones e ingresos a cuenta del IRPF, ver las bases de cotización, si tienes alguna obligación pendiente, consultar tu situación actual...

What city does my social security number belong to?

As mentioned at the beginning, the first two digits of the membership number correspond to the code of the city that issued the card.

Below you have a table with all the province codes of Spain:

CodeProvince CodeProvince CodeProvince
3Alicante/Alacant20Gipuzkoa26Rioja, La
1Araba/Álava18Grenada38Santa Cruz de Tenerife
7Balears, Illes23Jaen43Tarragona
13Ciudad Real32Ourense52Melilla
14Córdoba34Palencia53Other territories
15Coruña35Palmas, Las66Foreign

Can I have several social security numbers?

Social security number

No, it is impossible. Each person has only one number and cannot have more.

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