You are also considered a tax resident if you have been in the United States for a "weighted" total of at least 183 days during the previous three years -- unless you spend fewer than 30 days in the United States in the current year. To determine the weighted total number of days, each day in the current year counts as one, each day in the previous year counts as only 1/3 of a day, and each day in the year before that counts as only 1/6 of a day. This latter rule does not apply to certain foreign government employees, teachers, students, and professional athletes.

If you spend fewer than 183 days of the current year in the United States and have a tax home in another country, you will avoid being classified as a tax resident. If you have no other tax home, however, the IRS might decide that your tax home is the United States and that you are attempting to hide that fact by living there fewer than 183 days per year.

There are other exceptions to these tax rules based on tax treaties between the U.S. and your home country. If you are unsure of your situation, consult a tax accountant or lawyer. Also see IRS Publication 519, U.S. Tax Guide for Aliens, available at www.irs.gov.

If you are a tax resident, you must file U.S. tax return Form 1040 each year by April 15th, and pay tax on all income earned in the United States. (Unlike green card holders, you don't pay tax on your worldwide income.)

Failure to follow U.S. tax laws may be considered a criminal offense, leading to punishment, revocation of your nonimmigrant visa, and deportation. Failure to comply with U.S. tax laws can also make it more difficult for you to obtain permanent residency (a "green card") should you ever want it. To find out exactly how to comply with U.S. tax laws, consult a tax professional or visit the IRS website at www.irs.gov.