Everyone who has some sort of income in US has to file his taxes on an annual basis, at April 15th. Since the US tax system is extremely complicated unless your tax situation is pretty simple you'll have either to invest a few days of reading through the various IRS (Internal Revenue Service) publications, use a professional or pay ($100-200) to a tax professional.
For a foreign person the situation is even more complicated since there are three possible tax statuses which depend on various circumstances: Non-Resident Alien, Resident Alien and a Dual-Status Alien. Non-Resident Alien has the least financial bond to US and therefore is not eligible to any tax credits or tax deductions. Resident Alien has more financial bond to US than his home country, and he is eligible to all the credits and deductions. Dual-Status is a mixed status which applies only at the beginning or at the end of your US stay.
Except the federal taxes you have to pay also state and city taxes, as also the social security and healthcare taxes. Moreover your residency tax status at the state and city can be different from your federal residency tax status.
Here are some stuff to check:
- See if you have a Tax treaty. For example, Israeli postdocs don’t pay Federal and State/City taxes for 2 years (not tax years, actual 2 years).
- For the first 2 years if you are under tax treaty, you are considered as a Non-Resident Alien, which means you cannot get any of the tax credits and deductions a citizen gets. To file your taxes use the Glacier software provided by Columbia for free. Note, that during your second year you will probably start paying your state/city taxes since you will become a state resident.
- After the first 2 years use the TurboTax software to file your taxes electronically.
- Don’t forget to apply for ITIN numbers for your kids using a W-7 form). Those are Tax IDs used by people who are not eligible for a SSN, and allow you to claim all the tax deductions and tax credits for your kids. You can only do so when you become a Resident Alien. The application is submitted with your tax return (form 1040).