I agree with my colleagues, in that it depends on the local office. Just to give you an example of times, I just had a similar case approved this week in San Diego, at the Chula Vista field office, that I submitted the first week of November. So it took just under 3 months for the permanent residency to be approved, and they received the employment authorization a couple weeks prior. I have another case that I submitted the first week of January in Santa Ana, CA, that just received an interview for the first week of March. So, assuming it is approved at the interview, that case will have taken around 2 months. You can also check processing times for your local field office online at the link below.
It depends on the local office. It usually takes about 90 days to get the permit, but if the interview is scheduled before that, you may not get it unless for some reason you are not able to be approved for your green card at the interview.
Samuel Ouya Maina, Esq.
Law Offices of S. Ouya Maina, PC
332 Pine Street, Suite 707
San Francisco, CA 94104
The work permit is usually issued within 90 days of filing the application. Being scheduled for the interview in Philadelphia usually takes 4 to 5 months from filing, but I've seen it happen even quicker recently.
You should get your work permit before you interview. The permit takes about three months. If there are no problems the interview for the green card takes about six months. The card is produced about 2 months after the successful completion of the interview.
The answer provided here is general in nature and does not take into account other factors that may need to be reviewed for a more precise answer. You should consult with an immigration attorney before taking any action. The answer here is not intended to create an attorney-client relationship.