Generally, you must pay U.S. tax on income earned abroad in the same way you pay tax on income earned in the United States. If you are an employee of a U.S. company, your employer probably withholds income tax from your pay. If income tax is not withheld or if not enough tax is withheld, you might have to pay estimated tax.taxmap/pubs/p593-002.htm#en_us_publink1000219337
You may be able to have your employer discontinue withholding income tax from all or a part of your wages. You can do this if you expect to qualify for the income exclusions under either the bona fide residence test or the physical presence test. See Publication 54 for information. taxmap/pubs/p593-002.htm#en_us_publink1000219338
U.S. payers of benefits from employer-deferred compensation plans (such as employer pension, annuity, or profit-sharing plans), individual retirement plans, and commercial annuities generally must withhold income tax from the payments or distributions. To claim exemption from withholding, you must provide the payer of the benefits with a residence address in the United States or a U.S. possession unless you certify to the payer that you are not a U.S. citizen or resident alien or someone who left the United States to avoid tax.
For rules that apply to nonperiodic distributions from qualified employer plans and tax-sheltered annuity plans, get Publication 575, Pension and Annuity Income. taxmap/pubs/p593-002.htm#en_us_publink1000219339
Because foreign employers generally do not withhold U.S. tax from your wages, you may have to pay estimated tax if you are working abroad for a foreign employer. Your estimated tax is generally the total of your estimated income tax and self-employment tax for the year minus your expected withholding for the year.
When you estimate your gross income, do not include the income that you expect to exclude. You can subtract from income your estimated housing deduction in figuring your estimated tax liability. However, if the actual exclusion or deduction is less than you expected, you may be subject to a penalty on the underpayment.
If you qualify for the foreign earned income or housing exclusions, see Publication 505 to estimate your tax liability.
Use Form 1040-ES, Estimated Tax for Individuals, to estimate your tax. The requirements for filing and paying estimated tax are generally the same as those you would follow if you were in the United States.