A control number is a three digit or a four digit number printed on the credit card, which is stored in the magnetic strip of the card and does not show up on any bills or receipts with sellers. The control number serves as proof that you physically have the credit card at the moment of online shopping and also reduces the risk of fraud.

The place of the control number depends on the credit card. From your credit card, enter the control number into the designated fields according to the following instructions:

For American Express cards issued in Croatia beginning with the number '3775', there is a three digit control number printed on the back of the card you need to enter, otherwise you enter the four digit control number printed on the front of the card. For all other American Express cards, you need to enter the four digit number printed on the front of the card (see image)

More details available on www.americanexpress.hr

For Maestro, MasterCard and Visa you must enter the three digit number, which is printed on the back of the card (see image).
Older Maestro cards do not have a control number so you do not have to enter it in.