As of 2014, the typical processing time for Form I-485 is between four to eight months, according to the U.S. Citizenship and Immigration Services. Processing time depends on the service center in question. Applicants must apply to the service center responsible for their area of residence.
Applicants use Form I-485 to apply to the U.S. Citizenship and Immigration Services to change their immigration status to that of permanent resident, explains USCIS. It is the final step in the green card process. USCIS processing times show that while some service centers return applications regularly within three months, others take much longer. Delays of over a year are not uncommon.