What is the difference between Form 1040 and Form 1040-NR for F-1 visa holders?

U.S. tax law classifies individuals as either 'Resident Aliens' or 'Non-Resident Aliens' based on the Substantial Presence Test. International students on F-1 and J-1 visas are classified as 'Exempt Individuals' for their first 5 calendar years in the U.S., meaning they cannot count their days toward residency. Non-resident aliens are legally required to file Form 1040-NR (using specialized software like Sprintax or Glacier Tax Prep), pay taxes ONLY on U.S.-source income, and are legally exempt from 7.65% FICA (Social Security and Medicare) payroll taxes. Filing a standard Form 1040 (through TurboTax or FreeTaxUSA) as an F-1 non-resident alien is illegal and can jeopardize future H-1B or Green Card immigration applications.