Although no guarantees can be made, the average application processing time takes anywhere from 5-13 months from mailing your completed application until you receive your green card based on marriage. Don’t count on these numbers, however — many variables are involved, including shifting political winds.
Some of the variables include which State you live in, and the quality of the application you submit to the USCIS. The decision of whether to approve your application is normally made at the end of the green card interview; otherwise, you will be notified by mail. It is helpful to have the process done with a green card based on marriage lawyer NYC.
Recently it has been taking longer and longer to complete the process, and it will obviously take longer if you don’t file Form I-130 and Form I-485 simultaneously. The timeline could be even extended even further if the sponsor is a US permanent resident rather than a US citizen, as is often the case.