Money & tax

Your first tax year abroad: the 183-day rule and worldwide income

October 23, 2026 · ~7 min read

Changing your address takes a weekend. Changing your tax residency takes a calendar — one measured in days, whole tax years and filing deadlines, not in visa stamps. Plenty of families relocate mid-year assuming the new country taxes income the way the old one did, then spend the following spring filing in two places, surprised by both. This guide walks through the mechanics: how countries decide you have become "theirs" for tax, what Taiwan does with overseas income, what leaving Hong Kong involves, and where the first-year traps sit. The consistent conclusion: days, not the intentions printed on a visa, decide most of it.

This guide is educational only — not tax advice. Rules change, so treat the official sources linked below as the authority before you act.

Key takeaways

The 183-day count is the common global rule of thumb — not a universal law. Each country runs its own residency tests, and some weigh homes, family and intent as heavily as days.
Taiwan taxes residents on worldwide income: once a filing household's annual overseas income reaches NT$1,000,000, all of it enters the basic-income calculation for the minimum tax.
Hong Kong taxes Hong Kong-source employment income generally; leaving means a final salaries-tax settlement — there is no exit tax.
A visa is not a tax plan: residence rights and tax residency are run by two different systems.

Days, not addresses: the 183-day rule and its limits

The most common threshold worldwide is 183 days: spend 183 or more days in a country during a tax year, and you are usually treated as tax-resident there. Treat that as a rule of thumb rather than a law of physics. Each country applies its own tests, and several weigh other factors — a permanent home available for use, where your family and economic life actually sit, plain intention to settle — as heavily as the raw day count. The UK, for example, blends days with "ties" in its statutory residence test. The practical method: treat 183 days as the first screening question, then read the country's own residency rules on its official tax portal.

Taiwan: residents, worldwide income and the NT$1,000,000 trigger

Taiwan taxes its residents on worldwide income — not only Taiwan-source salary. For households with income from abroad, one number matters most: if a filing household's total overseas income for the year reaches NT$1,000,000, the entire amount — not just the excess — is counted into the "basic income" used for Taiwan's alternative minimum tax (最低稅負制). The basic income currently carries an exemption of NT$7,500,000 — raised from the long-standing NT$6,700,000 — with the excess taxed at 20%; tax already paid abroad on the same income can be credited. For readers who keep Taiwan tax residency while working overseas, or move back mid-year, this chain is the one to understand before filing season. The Ministry of Finance's official page on the minimum tax sets out the full calculation.

Hong Kong: what leaving the territorial system means

Hong Kong runs a territorial system: salaries tax generally applies to Hong Kong-source employment income only, and there is no general capital-gains tax — the Inland Revenue Department's own site is the authority. Leaving is structurally simple: settle the final salaries tax for the year of departure. There is no exit tax. The shock usually runs the other direction. Someone moving out of Hong Kong steps away from a system that ignored overseas investment gains, foreign rental income and much interest income — straight into systems that tax residents on all of it. The first foreign tax year is where that discovery gets expensive, which is exactly why the year of the move deserves a plan rather than an assumption.

The two systems at a glance

	Taiwan	Hong Kong
Residents taxed on	Worldwide income	Hong Kong-source employment income (generally)
Overseas income	Counted into basic income once the household's total reaches NT$1,000,000	Generally outside salaries tax
Capital gains	Within the minimum-tax chain for overseas income	No general capital-gains tax
On departure	Residency tests decide the filing	Final salaries-tax settlement; no exit tax

The traps of the year of the move

The year you relocate is almost never a clean tax year anywhere. The classics:

Partial-year residency in two places. Two filings, two sets of forms, two deadlines — often sitting on different tax years underneath (Taiwan files on the calendar year; the UK's tax year ends in early April).
A balancing payment that lands months later, after you assumed the whole matter was closed.
Assuming the new country works like the old one — joint versus individual filing, the treatment of investment income, and the allowance system can all differ.
Dual-residency claims, where both countries consider you resident and treaty tie-breakers decide which one wins.

A visa is not a tax plan

Residence rights and tax residency are administered by different systems, and only one of them cares what your visa says. A digital-nomad visa grants the right to stay — and once the day count tips, it can hand you a brand-new tax residency with it. Golden visas are easier still to mistake for tax strategies: Portugal's celebrated NHR regime has ended, so new arrivals face the standard system rather than the favourable one that drew many of them — our golden-visa reality check explains. The rule of thumb: secure the residence right first, then build the tax plan separately, on its own days.

The honest box: see a licensed cross-border accountant before the move, not after

Every serious source converges on the same advice: engage a licensed cross-border accountant or tax adviser before relocating, not after the first unexpected assessment. The year of the move is when professional fees are cheapest relative to what they prevent — dual filings, missed foreign-tax credits and mistaken residency claims are all fixable in advance and expensive afterwards. This guide is educational and cannot apply rules to your case; a professional licensed to see both countries' rules is the person who can.

Key numbers last verified: October 2026

Taiwan overseas income: a filing household's annual overseas income reaching NT$1,000,000 brings the full amount into the basic-income (最低稅負制) calculation. Source: Ministry of Finance tax portal — 最低稅負制
Taiwan basic-income exemption: NT$7,500,000 (raised from NT$6,700,000); excess taxed at 20%, foreign tax paid creditable. Source: Ministry of Finance tax portal — 最低稅負制
Hong Kong: salaries tax generally applies to Hong Kong-source employment income; no general capital-gains tax; no exit tax on departure. Source: Inland Revenue Department
The 183-day threshold is a common rule of thumb, not a legal standard — each country's tax authority publishes its own residency tests.

Rules change — always confirm with the official portal before you apply.