US tax, explained.
The parts of the US system that catch out people whose other tax life is in Korea — identification numbers, filing status, state tax, and working for yourself.
Getting an ITIN (Form W-7)
A spouse or child without an SSN needs an ITIN before you can claim them. How Form W-7 works and why passports get held.
Choosing a Filing Status
Filing status changes your brackets, deduction and credits. Why a non-resident spouse makes this decision harder than it looks.
State Income Tax and Residency
States tax separately from the IRS and are not bound by tax treaties. Why leaving a state is harder than leaving the country.
Self-Employment Tax and Estimated Payments
US self-employment tax is 15.3% on top of income tax, and nobody withholds it for you. Why quarterly payments are not optional.
W-2 Employee or 1099 Contractor
The label on your paperwork decides who pays payroll tax, what you can deduct, and what protections you have. It is not a free choice.
When the IRS Writes to You
Most IRS letters are routine and have a deadline. What the notice number means, and why ignoring one is the expensive option.
Official sources
Every guide in this section cites its primary source. Rates and thresholds change each year — these are where the current figures come from.
- IRS — Individual Taxpayer Identification Number (ITIN)
- IRS — About Form W-7
- IRS — Filing Status
- IRS — Nonresident Alien Spouse
- IRS — State Government Websites
- IRS — Tax Treaties
- IRS — Self-Employment Tax
- IRS — Estimated Taxes
- IRS — Independent Contractor or Employee
- IRS — Understanding Your IRS Notice or Letter
- IRS — Tax Scams and Consumer Alerts
More from HanTaxPro
General information, not tax advice. Rules and thresholds change, and how they apply depends on your circumstances — confirm with a licensed professional before acting.