Which country do you actually pay tax in?
The usual rule is simple: you pay income tax in the country where you are tax resident and physically doing the work. Your employer's location decides very little. A developer living in Portugal working for a company in California pays Portuguese income tax, not Californian.
Where it gets complicated is when you move during the year, keep a home in two places, or spend long stretches somewhere on a tourist stay. Then you can trip the residency test in more than one country at once, and the treaty tie-breaker rules decide which one wins.
- Count your days. Most countries start with a day-count test, commonly 183 days in a tax year.
- Check secondary tests too: a permanent home, your family's location, or your centre of economic interest can make you resident on fewer days.
- Leaving a country does not always end residency. Several countries require you to deregister formally.
- Some countries, notably the United States, tax citizens on worldwide income regardless of where they live.
What is the 183-day rule and when does it break?
The 183-day rule is a rule of thumb, not a universal law. It says that once you have spent more than half the year in a country, that country treats you as resident and taxes your worldwide income.
It breaks in both directions. You can become resident somewhere in under 183 days if you rent a year-round home there, and you can stay non-resident past 183 days in a few countries with different tests. Never plan around the number alone.
| Trigger | What it usually means |
|---|---|
| Permanent home available | A home you can use year-round, owned or rented, can make you resident quickly. |
| Centre of vital interests | Where your family, bank accounts, and main economic ties sit. |
| Habitual abode | A repeated pattern of staying, even across several short trips. |
| Registration | Some countries treat registering an address or a business as a declaration of residency. |
Why does a US company ask you for a W-8BEN?
Form W-8BEN is a short declaration to the US company, not something you send to the IRS. On it you confirm you are not a US person and name your country of tax residence. With it on file, the company can pay your invoices in full instead of holding back US withholding tax.
Individuals sign the W-8BEN. If you invoice through your own company, the equivalent is W-8BEN-E. It expires at the end of the third calendar year after signing, so most clients ask for a fresh one every few years.
- Give your legal name and residential address, not a mailbox service, or the form can be rejected.
- Enter your local tax identification number so the treaty rate can apply.
- Sign before your first invoice. Payments released without it can have up to 30% withheld.
- Never send bank details or ID to someone who has not yet sent you a written offer or contract.
How does your hiring model change your tax bill?
The way a borderless company engages you decides who files what. Our guide on contractor, EOR, and direct hire covers the employment side; here is the tax consequence of each.
| Independent contractor | Employer of Record | Local entity employee | |
|---|---|---|---|
| Who withholds tax | Nobody. You file and pay. | The EOR, at source | The employer, at source |
| Social contributions | Your responsibility | Split as local law requires | Split as local law requires |
| Filing burden | Quarterly or annual returns, plus bookkeeping | Usually an annual return only | Usually an annual return only |
| Deductible expenses | Equipment, coworking, software, part of home costs | Very limited | Very limited |
| Cross-border VAT | May apply; often reverse charged | Not your concern | Not your concern |
Do you charge VAT or sales tax to a foreign client?
If you invoice as a business, your local VAT or GST rules follow you rather than your client. In most of Europe, services sold to a business in another country are reverse charged: you invoice without VAT and add a note saying the reverse charge applies, and your client accounts for it at their end.
Selling to a client outside the VAT area is normally outside scope entirely. Either way, you may still have to register once your turnover passes a threshold, and you still report the sales on your own return.
What should you set up in your first month?
Getting this right early costs an hour or two. Getting it wrong costs penalties and interest.
- Register the correct legal form locally before your first invoice.
- Open a separate business account so personal and business money never mix.
- Put aside a fixed share of every payment for tax, and treat it as untouchable.
- Diarise your prepayment or quarterly dates; first-year contractors are caught out by these more than anything else.
- Track your days in each country from day one if you travel at all.
- Book one session with a local accountant who has handled foreign clients before.
Frequently asked questions
+Do I pay tax where my employer is based?
Almost never. Income tax follows where you are tax resident and physically working, not where the company is registered. The main exception is US citizens and green card holders, who file US returns on worldwide income wherever they live.
+Does a W-8BEN mean I owe US tax?
No, the opposite. It tells the US company that you are not a US taxpayer and that a treaty rate applies, so it can pay your invoices without withholding up to 30% for the IRS. You keep paying tax in your own country.
+How long is a W-8BEN valid?
Until the end of the third full calendar year after you sign it, so a form signed in 2026 lasts through 2029. You must send a new one sooner if your name, address, country of residence, or tax number changes.
+Can I be taxed twice on the same income?
Rarely, if a double taxation treaty exists between the two countries. The treaty either exempts the income in one country or gives you a credit for tax already paid in the other. Without a treaty, double taxation is possible, which is why treaty coverage is worth checking before a long stay.
+Do I need to register a company to invoice a foreign client?
It depends on your country. Some allow you to invoice as a registered sole trader with no company at all, others require a business registration before your first invoice. Check your local rule first, because backdating a registration is usually expensive.