India, July 7 -- Indian Green Card holders planning to apply for US citizenship may need to start budgeting for the process well before they become eligible, as naturalization costs continue to add to the overall expense of the immigration journey, immigration experts say.

According to the US Citizenship and Immigration Services (USCIS), the government currently charges $710 for online naturalization applications filed through Form N-400 and $760 for paper submissions. In addition to these filing fees, applicants may also incur expenses related to legal assistance, documentation and other professional services, depending on their individual circumstances.

For a family of four applying together, government filing fees alone can exceed $2...