Last verified with Chinese Government sources:
Chinese tax residence turns on a day count, and the day count is stricter than almost everyone assumes. Under the 2019 announcement from the Ministry of Finance and the tax administration, a day only counts if you were in China for a full 24 hours — so arrival days and departure days do not count at all. Weekend commuters to Hong Kong sit far closer to the line than they think, in the opposite direction from the one they expect. This counts the days for you.
It counts days of presence under the 24-hour rule, and flags a single absence long enough to restart the six-year clock. It does not calculate tax, it knows nothing about your income, your treaty position or your domicile, and it is not advice. Domicile is a separate test that can make you resident regardless of days. If real money turns on the answer, pay a China-qualified adviser — and read the tax guide first, which sets out the brackets, the deductions and the six-year rule in full.
The rule, in one paragraph
There are two independent residence tests and either one makes you a resident. The first is domicile — habitual residence by reason of household registration, family or economic interests — which catches almost no foreigner. The second is the one that bites: presence in China for 183 days or more, cumulatively, in a calendar tax year. There is no part-year residency; status is decided for the whole year.
Day counting is where people go wrong. A day counts only if you were in China for the full 24 hours. Cross to Hong Kong on a Friday evening and come back on the Sunday evening and none of those three days counts — the departure day and the return day are each under 24 hours, and you were not in China in between. That is the calculation this tool performs.
The six-year rule, and the trap inside it
A resident's non-China-sourced income paid by a non-China entity stays outside the Chinese net while the run of consecutive years at 183 days or more is fewer than six. The run breaks in exactly two ways: a year under 183 days, or a single continuous absence of more than 30 days in a year you were otherwise present 183 days or more. The word that trips people is single — one unbroken trip. Several shorter absences adding up to thirty-odd days do nothing at all.
The clock was reset to zero on 1 January 2019, which is why this tool will not accept an earlier year.
Use it, embed it, check it
This page is free to link to and quote. The rule it implements is published — the 2019 announcement is on gov.cn ↗ — and if you think the arithmetic is wrong I would rather hear about it than not: [email protected].