The IRS publishes its official list of country codes at irs.gov/e-file-providers/country-codes, and that page is the single most reliable place to find them.1Internal Revenue Service. Country Codes These two-letter codes appear on nearly every international tax form, from the foreign tax credit to withholding certificates for foreign persons. They look like the familiar ISO 3166 codes used on passports and shipping documents, but many of them differ, and using the wrong one can delay processing or cost you a credit you were entitled to claim.
Where the Official List Lives
The IRS maintains a single, publicly available country code list at irs.gov/e-file-providers/country-codes. The page was last updated in September 2025 and includes every two-character code the IRS accepts on electronically filed returns.1Internal Revenue Service. Country Codes The 2026 instructions for Form 1042-S point filers to that same page, confirming it as the authoritative reference across forms.2Internal Revenue Service. Instructions for Form 1042-S (2026) The Form 1116 instructions repeat the guidance in the Line i section, where you identify the foreign country or U.S. territory.3Internal Revenue Service. Instructions for Form 1116 (2025)
The list changes. A November 2024 update, for example, added the code “US” for the United States, allowing it to appear on Forms 926, 1118, 3520, and 8805.1Internal Revenue Service. Country Codes Pull the current version for the tax year you are filing rather than relying on a saved copy from a prior year.
IRS Codes Are Not ISO Codes
This is where most mistakes happen. If you grab a country code from a passport database, a shipping form, or an internet lookup tool, there is a real chance it will not match what the IRS expects.
A few examples from the current IRS list show the problem:1Internal Revenue Service. Country Codes
- Germany: the ISO code is “DE,” the IRS code is “GM.”
- Japan: the ISO code is “JP,” the IRS code is “JA.”
- Australia: the ISO code is “AU,” the IRS code is “AS.”
- Austria: the ISO code is “AT,” the IRS code is “AU.”
Notice that the ISO code for Australia (“AU”) is the IRS code for Austria. Swapping those two would attach your foreign tax credit to the wrong country. Canada (“CA”) happens to match between the two systems, which can create false confidence that the lists are interchangeable. They are not. Look up every code on the IRS list directly.
One more overlap to know about: FBAR filings (FinCEN Form 114) use standard ISO 3166-1 two-letter codes, not IRS codes.4Financial Crimes Enforcement Network. FBAR Line Item Filing Instructions If you file both Form 8938 and an FBAR in the same year for the same account, you may need different codes on each form.
Forms That Require a Country Code
Country codes show up on a wide range of IRS forms. The ones you are most likely holding fall into three groups.
Form 1116, Foreign Tax Credit
Form 1116 is how U.S. citizens and residents offset their domestic tax bill with income taxes paid to a foreign government.5Internal Revenue Service. Foreign Tax Credit You enter the country code on Line i and use separate columns in Part I and separate lines in Part II for each country where you earned income or paid taxes.3Internal Revenue Service. Instructions for Form 1116 (2025) If you paid taxes to more than three countries in the same income category, attach additional sheets following the same format.
W-8 Series, Withholding Certificates for Foreign Persons
Foreign individuals and entities receiving U.S.-source income use the W-8 forms to establish foreign status and, where a treaty applies, claim a reduced withholding rate. Form W-8BEN certifies a foreign individual’s status as beneficial owner of the income; Form W-8ECI certifies that income is effectively connected with a U.S. trade or business.6Internal Revenue Service. About Form W-8 ECI Both require a country code so the withholding agent knows whether a treaty applies and what rate to use. Without the correct code, the agent defaults to the statutory 30 percent rate on most U.S.-source income.7Office of the Law Revision Counsel. 26 USC 1441 – Withholding of Tax on Nonresident Aliens
Form 1042-S, Reporting Withholding on Payments to Foreign Persons
Withholding agents who pay income to foreign persons file Form 1042-S to report the amount paid and tax withheld. The 2026 instructions require the two-character codes from the IRS list and specify that a treaty-based exemption code can be used only if the country code in Box 13b corresponds to a country with which the United States has an income tax treaty.2Internal Revenue Service. Instructions for Form 1042-S (2026) Publication 901 is the reference for which countries have such treaties and what reduced rates apply.8Internal Revenue Service. About Publication 901, U.S. Tax Treaties
Form 8938, Foreign Financial Asset Reporting
Form 8938 (Statement of Specified Foreign Financial Assets) requires you to identify the country where each foreign account or asset is maintained, using the IRS codes. The separate FBAR obligation covers the same accounts but uses ISO codes, as noted above.4Financial Crimes Enforcement Network. FBAR Line Item Filing Instructions
U.S. Territory and Possession Codes
Income from U.S. territories gets its own set of codes, and several of them diverge sharply from what you might expect. The most common ones on the current IRS list include:1Internal Revenue Service. Country Codes
- Puerto Rico: RQ
- U.S. Virgin Islands: VQ
- Guam: GQ
- American Samoa: AQ
- Northern Mariana Islands: CQ
These codes matter because income from U.S. possessions often qualifies for the foreign tax credit. You can claim taxes paid to a possession government on Form 1116 the same way you would for a foreign country.5Internal Revenue Service. Foreign Tax Credit FBAR filers should note that FinCEN explicitly warns against using U.S. territory codes from the ISO list in country fields, since those overlap with U.S. Postal Service state abbreviations.4Financial Crimes Enforcement Network. FBAR Line Item Filing Instructions
When Nothing on the List Fits: “OC” and “XX”
The IRS provides two special designations for situations where a standard country code does not fit.
“OC” stands for “Other Country” and is used when you paid taxes to a jurisdiction that does not appear on the IRS list.1Internal Revenue Service. Country Codes The Form 1042-S instructions direct filers to enter “OC” only when the country of residence is absent from the published list.9Internal Revenue Service. Country Codes for Form 1042-S If you use “OC,” attach a statement identifying the country and explaining the tax paid. This code draws scrutiny precisely because it lacks jurisdictional specificity, so avoid it when a standard code exists.
“XX” means “Unknown country” and appears in the IRS withholding database used to process Form 1042-S information.10Internal Revenue Service. 3.22.111 Chapter Three and Chapter Four Withholding Database A withholding agent might use “XX” when the payee’s country of residence cannot be determined. It is a temporary placeholder; once the country is established, the record should be corrected. Treat both “OC” and “XX” as last resorts, not as shortcuts for situations where a few minutes of research would identify the correct code.
What a Wrong Code Can Cost
An incorrect country code can look like a minor data-entry mistake. When it changes the amount of foreign tax credit you claim or the withholding rate applied to a payment, the dollar consequences can be significant.
If a wrong code leads to an underpayment of tax, the IRS can assess an accuracy-related penalty of 20 percent of the underpayment when the error reflects negligence or disregard of IRS rules. For individuals, a “substantial understatement” penalty at the same 20 percent rate applies when the tax shown on the return is understated by the greater of 10 percent of the correct tax or $5,000.11Internal Revenue Service. Accuracy-Related Penalty
Foreign asset reporting carries its own structure. Failing to file Form 8938 or filing it with incorrect information triggers a $10,000 penalty. If the problem is not corrected 90 days after the IRS sends a notice, an additional $10,000 penalty accrues for each 30-day period the failure continues, up to a $50,000 maximum in additional penalties per failure.12eCFR. 26 CFR 1.6038D-8 – Penalties for Failure to Disclose Married couples filing jointly face these penalties jointly and severally, meaning the IRS can collect the full amount from either spouse.
Before you file, verify every country code on your return against the current IRS list at irs.gov/e-file-providers/country-codes. The minute it takes is cheap insurance against a rejected credit or a penalty notice.