Do I get double-taxed on the same income?

While the US citizenship-based tax system means you are potentially subject to tax in both the US and your country of residence, the US provides several mechanisms to prevent actual double taxation on the same income. In practice, most expats do not pay full tax to both countries.

The Foreign Tax Credit (FTC) is the most direct solution. It provides a dollar-for-dollar credit against your US tax for income taxes paid to a foreign government. If you earn $100,000 and pay $25,000 in foreign income taxes, and your US tax on that income would be $22,000, the FTC eliminates your entire US liability on that income, with $3,000 in excess credits to carry forward.

The Foreign Earned Income Exclusion (FEIE) takes a different approach by excluding up to $126,500 (2024) of foreign earned income from US taxation entirely. This is particularly beneficial in low-tax countries where you have little or no foreign taxes to claim as credits.

Tax treaties between the US and approximately 65 countries provide additional protections by allocating taxing rights, reducing withholding rates, and preventing double taxation on specific income types like pensions, government salary, and business profits.

However, there are situations where some residual double taxation can occur: on income types not covered by the FEIE (such as investment income in a low-tax country), when there is a tax rate differential that credits cannot fully offset due to category limitations, on self-employment tax (which the FEIE does not reduce), and in countries without a US tax treaty where certain income types lack clear relief.

Social security/social insurance taxes can also create double taxation unless a Totalization Agreement exists between the US and your country of residence. About 30 such agreements are currently in effect.

The key to minimizing double taxation is proper planning and expert preparation. The order in which you claim credits and exclusions, the income categories you select, and the strategic use of treaty provisions can significantly impact your total tax burden across both countries.