An international move changes more about your tax situation than most people expect going in — residency status, double taxation, and retirement account portability all need answers before, not after, you land.
Residency status isn't automatic
Most countries use specific tests — days physically present, location of your primary home, where your economic ties sit — to determine tax residency. It's possible to be considered a tax resident of your old country and your new one simultaneously for a transition period, which is when double-taxation treaties matter most.
Check for a tax treaty
Most major economies have bilateral tax treaties designed to prevent the same income being taxed twice. These treaties typically determine which country has primary taxing rights and provide credits for tax paid elsewhere — but claiming the benefit usually requires specific paperwork, not something that happens automatically.
Retirement accounts often don't transfer cleanly
A 401(k), RRSP, or superannuation account generally can't simply move with you into an equivalent foreign account — each country's tax-advantaged retirement system only recognizes its own. Understand the tax treatment of leaving funds in place versus withdrawing before you move, since early withdrawal often triggers a tax event.
Payroll withholding needs updating on both ends
Your new employer withholds tax based on your new country's rules from day one, but your old country's system may not automatically know you've left — failing to formally close out tax residency can result in continued filing obligations you didn't expect.
Once you know your new salary, compare take-home pay using the calculator for your destination: US, UK, Canada, or Australia.