The NVC is a facility that is responsible for processing immigrant visa applications after they have been approved by the USCIS. Each case received by the National Visa Center is assigned its case number.
1. After your I-130/I-140 petition has been approved, you can get your NVC case number from the NVC. Do this by calling the NVC at (603) 334-0700. First provide your USCIS receipt number, which is in your I-797 Notice of Action 1 (NOA1).
If your visa package has been received by the facility, either the automated voice recording or a human operator can give you your NVC case number.
2. Write down your case number. It is a series of three letters and 10 numbers with no dashes or spaces. An example NVC case number looks like this: MNL2013524001.
Split the figures as follows: LLL NNNN NNN NNN, where "L" is a letter and "N" is a number.
4. Read the three letters from the left. This is the code for the U.S. consulate that has jurisdiction over the visa applicant's location. It is where you will get a visa interview. For example, "MNL" refers to the U.S. consulate in Manila.
Read the first four numbers following the letters. In this example it is "2013." This is the year that the NVC received the visa application.
Read the next three numbers. This is the day of the year in which the case was received. It is the figure minus 500. For example, "524" means NVC got the package on the 24th day of the year, January 24.
Read the last three numbers in the case number. It tells you the order it was assigned to the consulate that day. In this example, it is "001" so it was the first case created for the Manila consulate on Jan. 24, 2013.