Moving abroad? A practical tax checklist before you sign the offer
An offer in another country looks great on paper. Then you remember tax exists — and that the gross number on the offer letter has very little to do with what hits your account. Before you sign, walk through this checklist. Most of it costs you nothing but an hour of reading and a thoughtful conversation with HR. Getting it wrong can cost you a year of net income.
Pin down your residency date
Tax residency rules vary wildly. The UK's Statutory Residence Test, Germany's 183-day rule, Spain's centre-of-vital-interests test and the US's substantial-presence test all sound similar and behave differently. Confirm exactly when you become tax-resident in the new country — and when you cease to be one in the old. The overlap month is where most expensive mistakes hide.
Check the double-tax treaty
Most major countries have a bilateral tax treaty. Read the relevant article for employment income, dividends, pensions and capital gains. The treaty decides which country gets first crack at the tax and how the other gives credit. If there is no treaty, you may pay full tax in both places. The US is its own category — citizenship-based taxation means Americans owe forever, treaty or not, until they renounce.
Cost out the social contributions
In France, Belgium, Germany and the Nordics, employee social contributions dwarf income tax for mid-range salaries. Most of them do not transfer with you when you leave. If you're 35 and planning a five-year stint in Paris, you'll likely never see most of what you paid into the French pension. Decide whether you treat that as a hidden tax or as buying into a system you'll genuinely use.
Stress-test your equity
RSUs and stock options that vest across borders are a minefield. Vesting that straddles your move date is often allocated pro-rata between countries, and the rules differ. If your offer is heavy in equity, talk to a cross-border tax adviser before you accept — not after the first vesting cliff. The cost is usually a few hundred dollars and routinely pays for itself many times over.
Model the after-tax number with our calculator
Use the destination country's GlobalTax calculator with your full target salary, then compare net-to-net against your current role. Don't compare gross numbers. A 30% gross raise that moves you from Dubai to Berlin is almost always a pay cut once income tax, solidarity surcharge, church tax and Sozialversicherung land on your payslip.