If you’ve been living outside of the United States, you will need to determine if you’re required to file a U.S. tax return.
The first question you should ask is whether you were a U.S. citizen on the last day of the tax year.
If you answered “no” to this question, then ask whether you were a U.S. resident alien on the last day of the tax year. (For federal tax purposes, you are a resident alien if you have a green card; meet the substantial presence test – living in the U.S. at least 31 days during that year, or 183 days during a 3-year period; or are married to a U.S. citizen.)
If you are either a U.S. citizen or a U.S. resident alien, you must file a tax return to report your worldwide income, unless your income is below the threshold amount. The rules are the same whether you’re living in the United States or abroad, and also apply to state, gift, and estimated taxes.
Filing thresholds are determined by your income, age, and filing status. The IRS determines these thresholds each year.
You may have to file a tax return even if your income is below the threshold amount for your filing status. Some examples include receiving certain self-employment income or U.S. source income.