How the FTC works
The basic principle: you pay income tax to Spain; you pay income tax to the U.S. on the same income; the FTC lets you credit the Spanish tax against your U.S. liability, reducing or eliminating the double taxation. The credit is claimed on Form 1116 (or Form 8833 for treaty-based positions) attached to your 1040.
The credit is limited to the U.S. tax liability on the same foreign income — you cannot use foreign taxes to reduce U.S. tax on U.S.-source income, and excess credits can be carried back or forward. Income must be categorized by "basket" (general income, passive income, etc.) for FTC limitation purposes, which adds complexity.
FTC and Beckham Law
Under Spain's Beckham Law, Digital Nomad Visa holders pay a flat 24% tax on Spanish-source work income. Whether this Spanish tax is fully creditable against U.S. tax depends on treaty provisions, the income category, and how the Beckham Law is treated under U.S. tax principles. This analysis is not straightforward, and is exactly why American nomads in Spain need a CPA who handles both Spanish and U.S. returns simultaneously — not two separate preparers working in isolation.
The general picture: for Americans earning $100,000–$200,000, paying 24% in Spain and using the FTC to offset U.S. liability, the total tax burden is typically lower than it would have been paying U.S. progressive rates alone. The specific outcome depends on income level, type, and treaty interaction. The Beckham Law guide explains the planning context; consult a qualified professional for your specific numbers.
FTC vs. FEIE: the choice
Most Americans living in Spain must choose an overall strategy: Foreign Tax Credit or Foreign Earned Income Exclusion (generally not both on the same income). For those earning above the FEIE exclusion amount (~$130,000) or with significant Spanish tax under Beckham Law, the FTC is typically the primary tool. Your U.S. tax preparer models both scenarios and recommends based on your specific income profile.
Potentially, in part. Spanish income tax paid under Beckham Law may be creditable against U.S. tax on the same income under the Foreign Tax Credit rules and the U.S.-Spain tax treaty. However, the mechanics are more complex than a simple dollar-for-dollar offset — the creditability depends on the income category, how Spain characterizes the tax, and the interaction with treaty provisions. This is one of the most technically complex areas of American expat taxation. Work with a dual-qualified CPA.
You can use both in the same year, but not on the same income. If you exclude income under the FEIE, you cannot also claim the FTC on that same income. The FEIE and FTC can apply to different portions of your foreign income, but the interaction is complex and requires careful planning.