If you are applying for permanent residence in the United States, how do you figure out how long it will take? This seems like an easy question, but like many things with immigration, it can be complicated.
First, for some employment-based categories, pre-approval from Department of Labor (DOL) is required before even contacting Department of Homeland Security (DHS). This is called "labor certification" or "PERM". It can take several months.
Second, after receiving the PERM approval or initially for other situations, you file an application or petition with U.S. Citizenship & Immigration Service (USCIS) (which is part of DHS). USCIS lists "processing times" on their webpage. This means that it will take approximately the time listed to decide whether to approve that application/petition. Note that these times are already out of date when published, so real processing times vary.
If there is no waiting line in the category in which you are trying to immigrate (such as for spouses and minor children of U.S. citizens, or parents of U.S. citizens that are 21 or older, or for certain employment-based categories), you can then file for the actual "green card".
This application often may be made in the United States if you are here legally (and even in some cases if you are not - but that is another question). This is called "adjustment of status" (or "AOS"). AOS usually takes four to six months from the time of filing - if no waiting line has developed in the meantime.
If you are not in the U.S. or cannot stay during the whole process, the green card processing can be done by the U.S. consulate in your home country or current country of residence. This is called "consular processing" (CP) and is administered by the Department of State (DOS). Whether to do AOS or CP is a decision that must be made with your immigration attorney, as it can be complicated. CP processing times vary by country and situation, but usually are three to four months.
However, if there is a waiting line in your category, you cannot file AOS or do CP at all. You have to wait until your "priority date" (PD) is "current". What?
The "priority date" is determined usually by when the first process in your case is filed. For PERM cases, this is when the PERM is filed. For family-based cases, it is when the petition is filed. Sometimes an old PD can be recaptured if you have another immigration petition approved. This is another question to sort out with your immigration lawyer.
"Current" means the waiting line has passed your PD or the category is listed as "C" on the Visa Bulletin. The Visa Bulletin is published monthly at http://www.travel.state.gov/visa/bulletin/bulletin_5759.html.
If your priority date is May 1, 2007, your category would need to have reached May 2, 2007, for your PD to be "current" (or there would be a "C" in your category). In other words, the dates listed on the Visa Bulletin are those before which the US government is issuing visas for permanent residence in each category.
If the Visa Bulletin says "U" in your category, it means that immigrant visas are "unavailable". In other words, no one can file in that category that month.
The Visa Bulletin is published around the 15th of each month for the following month. You can check it on-line to determine your PD progress.
But wait! One more thing you should know: PDs can move forward OR backward OR stand still. The DOS determines the expected demand for visas and puts the date where they think it will allow them to use up all the available immigrant visas each fiscal year. Sometimes they guess wrong and have to move the date backward, or make a category "unavailable".
Therefore, if your PD is May 1, 2009, and the current PD listed is May 1, 2007, you cannot say that you will be able to file AOS or CP in two years. It is impossible to know if the line will move month-for-month or a week for each month or a day for each month or even go backward at times. Or it could jump several months or even years forward. We have seen it do all those things.
For example, recently a waiting line was established for "EB2" (employment-based second category) "all other countries". This had not happened in recent memory. People expecting to file the AOS or CP from this category were surprised and we had to develop new strategies to maintain their immigration status.
When will you receive your green card? The answer often is "we don't know for sure" - and no one else does either. To plan as accurately as possible - and if you have questions - contact your immigration lawyer rather than relying on published "processing times" or informal internet information.