US citizens and resident aliens
If you are a US citizen or resident alien, you are subject to US federal income tax on your worldwide income, regardless of where you live. This means that you will have to file a US tax return even if you live and work outside of the US. However, there are a few exceptions to this rule, such as the foreign earned income exclusion (FEIE) and the foreign housing exclusion (FHE).
Non-resident aliens
If you are a non-resident alien, you are generally only subject to US federal income tax on income that is earned from US sources. This means that you will not have to file a US tax return if you do not have any US-source income. However, there are a few exceptions to this rule, such as the substantial presence test (SPT).
Substantial presence test (SPT)
The SPT is a test that is used to determine whether a non-resident alien is considered a US resident for tax purposes. Under the SPT, a non-resident alien is considered a US resident for tax purposes if they spend 183 days or more in the US during a given year. If a non-resident alien is considered a US resident for tax purposes, they will be subject to US federal income tax on their worldwide income.
Exceptions to the SPT
There are a few exceptions to the SPT. For example, a non-resident alien who is a student or teacher at a qualified educational institution may be able to qualify for an exception to the SPT. Additionally, a non-resident alien who is a treaty-based alien may be able to qualify for an exception to the SPT.
How to determine your tax residency status
If you are unsure of your tax residency status, you should consult with a tax advisor. They can help you to determine whether you are a US citizen, resident alien, or non-resident alien. They can also help you to determine whether you are subject to US federal income tax.
Here is a table that summarizes the amount of time you can spend in the US without paying taxes, depending on your tax residency status:
- Tax residency status Amount of time you can spend in the US without paying taxes
- US citizen or resident alien Worldwide income is subject to US federal income tax, regardless of where you live
- Non-resident alien Generally only subject to US federal income tax on income that is earned from US sources
- Non-resident alien who qualifies for an exception to the SPT Generally not subject to US federal income tax, even if they spend more than 183 days in the US during a given year