New to the U.S. tax system? Start with your status.

You are a nonresident unless you meet one of two tests. The IRS says "you are considered a nonresident of the United States for U.S. tax purposes unless you meet one of two tests": the green card test or the substantial presence test (IRS residency status). The day-count test is explained step by step on the tax residency page. Tax residency is separate from immigration status, so a visa holder can be a resident for tax purposes.

You may be both. The IRS notes "you can be both a nonresident and a resident for U.S. tax purposes during the same tax year," which usually happens in the year you arrive in or leave the U.S., and then a dual-status return is needed (IRS). Dual-status returns follow their own rules on filing status and deductions, and they are easy to get wrong with consumer software. This is one place where having an Enrolled Agent prepare the return pays off. Bring your exact arrival or departure date; the split of the year starts there, and income before and after it is treated differently.

Sometimes. The IRS says residents of foreign countries "may be eligible to be taxed at a reduced rate or exempt from U.S. income taxes on certain items of income" under a treaty (IRS tax treaties). Students, researchers and teachers are common examples. Claiming a treaty benefit can require a form for your employer or payer, and sometimes a disclosure with your return; see tax treaty benefits.

Because she remembers what was new. Blaga earned her first MBA in Accounting in Sofia, Bulgaria, then a Master's in Accounting at Sam Houston State University. She learned U.S. rules as someone who already knew another system, which is the position many of her international clients are in. That background helps her explain U.S. concepts, such as worldwide income, dual status and estimated payments, without assuming you grew up with them. More about her on the about page.

• Your passport and visa or immigration documents, and travel dates in and out of the U.S. for the past three years.
• W-2s, 1042-S forms and any 1099s.
• Income records from your home country, if you may be a U.S. resident this year.
• Any prior U.S. returns and IRS letters.
• Your SSN or ITIN, if you have one.

It depends on your status. Once you are a U.S. resident for tax purposes, the U.S. generally taxes your worldwide income, including salary, rent, interest or a pension from abroad; the IRS notes that treaties generally do not reduce the U.S. taxes of U.S. treaty residents (IRS). A nonresident is generally taxed only on U.S. income. Foreign tax you paid on the same income may offset U.S. tax, so bring records of it. That keeps the same money from being taxed twice where the rules allow relief.