Within each category of green card (employment based, family based, etc.), there are various sub-categories. For Employment based sponsorship, the sub-categories depend on employer’s job requirements and your qualifications in case of employment based green card. For Family based sponsorship, your relationship to the sponsor. There is also an annual quota for each sub-category and an annual quota from a given country. Therefore, it takes a varying amount of time to be granted a green card based due to processing as the quota is the same for big countries like India or China, or some tiny island. Usually the wait is much higher for people that originate from larger countries.

In order to help the applicants, the U.S. Department of State publishes Visa Bulletin every month for the next month that describes the cut off dates for people who are waiting for green card in various categories. These dates are for the priority dates which are based on when you filed your green card. In other words, it says that if you are in X category, and if your green card was applied before MM/DD/YYYY, your priority date will be current next month so you can proceed for final processing of your green card any time during the next month.