The foreign tax credit limitation on Form 1116 restricts the credit to the amount of U.S. tax attributable to income that is foreign-sourced, preventing taxpayers from offsetting U.S. tax on U.S.-source income with foreign taxes paid. Instructions for Form 1116, Internal Revenue Service, U.S. Department of the Treasury, explain that the limitation is computed by determining the portion of your worldwide U.S. taxable income that is foreign-source and applying the U.S. tax rate to that portion to produce the allowable credit.
Calculation formula
The basic computation equals the ratio of foreign-source taxable income to worldwide taxable income, multiplied by your U.S. tax liability on that worldwide taxable income. First, calculate foreign-source taxable income after allowable deductions and allocations to foreign-source income and to each income category required by Form 1116. Then divide that amount by total taxable income before foreign tax credits. Multiply the resulting fraction by the U.S. income tax liability computed on the same total taxable income; the product is the foreign tax credit limitation. The Instructions for Form 1116, Internal Revenue Service, U.S. Department of the Treasury, and Publication 514, Internal Revenue Service, U.S. Department of the Treasury, set out these steps in detail and describe required allocations among income categories such as general, passive, or foreign branch income.
Causes and consequences
This rule arises from the dual goals of alleviating double taxation while protecting the U.S. tax base. By limiting the credit to U.S. tax on foreign-source income, the policy prevents taxpayers from reducing U.S. tax on U.S.-source income with foreign taxes paid elsewhere. Because taxpayers must allocate expenses and deductions between foreign and domestic sources, the limitation can be sensitive to how income is categorized and how expenses are apportioned. Practically, this affects U.S. citizens and residents living abroad, multinational investors, and entities with cross-border operations. Cultural and territorial nuances matter: expatriates in high-tax European or Nordic jurisdictions may face sizable foreign taxes that exceed the limitation, while residents in low-tax territories may have little credit to claim.
If foreign taxes paid exceed the limitation, the excess may generally be carried back one year and carried forward ten years per Publication 514, Internal Revenue Service, U.S. Department of the Treasury, or alternatively claimed as a deduction. Treaty benefits, sourcing rules, and special territorial rules can alter the calculation, so taxpayers commonly consult qualified tax professionals and the IRS instructions when completing Form 1116.